Magnetic position sensor system with high accuracy

Abstract

The invention relates to a magnetic position sensor system with high accuracy. A position sensor system (100) comprises a magnetic source (102) and a sensor device (101) movable relative to the magnetic source. The magnetic source comprises a first track (T1) of alternating magnetic poles and a second track (T2) of equal number of alternating magnetic poles but phase-shifted by 180° relative to the first track. The sensor device is configured to measure a plurality of magnetic field components, comprising a first magnetic field component at a first sensor position (A) facing the first track (T1) and a second magnetic field component oriented parallel to the first magnetic field component at a second sensor position (B) facing the second track (T2); and to derive a first difference signal (diff1) and a second difference signal (diff2) from the plurality of magnetic field components and to determine a position based on these difference signals.

Description

Technical Field

[0001] The present invention relates generally to the field of magnetic position sensor systems, and more particularly to linear or angular position sensor systems. Background Art

[0002] Magnetic position sensor systems, in particular linear or angular position sensor systems, are known in the art. They offer the advantage of being able to measure linear or angular position without physical contact, thus avoiding mechanical wear, scratches, friction, and other issues.

[0003] There are many variations of position sensor systems that address one or more of the following requirements: using simple or inexpensive magnetic structures, using simple or inexpensive sensor devices, being able to measure over a relatively large range, being able to measure with high accuracy, requiring only simple algorithms, being able to measure at high speeds, being highly robust to positioning errors, being highly robust to external interference fields, providing redundancy, being able to detect errors, being able to detect errors and correct errors, having a good signal-to-noise ratio (SNR), etc.

[0004] Often two or more of these requirements conflict with each other, so a trade-off needs to be made.

[0005] There is always room for improvement or substitution. Summary of the Invention

[0006] It is an object of embodiments of the present invention to provide a position sensor system that is highly insensitive to external interference fields.

[0007] It is an object of embodiments of the present invention to provide a position sensor system with improved accuracy, eg with increased sensitivity and / or increased resolution.

[0008] It is an object of embodiments of the present invention to provide a position sensor system suitable for use in an industrial, robotic or automotive environment.

[0009] An object of embodiments of the present invention is to provide a position sensor system in which the cost of the position sensor device is reduced (eg, smaller chip area).

[0010] It is an object of embodiments of the present invention to provide a position sensor system in which the mounting requirements of the sensor device are relaxed.

[0011] It is an object of embodiments of the present invention to provide a position sensor system that is more robust to aging effects, eg aging effects related to misalignment, mechanical wear, temperature changes, demagnetization, etc.

[0012] These objects and other objects are achieved by embodiments of the present invention.

[0013] According to a first aspect, the present invention provides a position sensor system for determining a position of a sensor device (e.g. x), the sensor device is movable relative to the magnetic source along a predefined path or the magnetic source is movable relative to the sensor device along a predefined path, the position sensor system comprising: a magnetic source comprising a first plurality (e.g., N1) of alternating magnetic poles arranged along a first track, and comprising a second plurality (e.g., N2) of alternating magnetic poles arranged along a second track, wherein centers of the magnetic poles are separated by a predefined (e.g., linear or angular or circumferential) pole pitch (e.g., pp); wherein a centerline (e.g., C1) of the first track (e.g., T1) is separated from a centerline (e.g., C2) of the second track (e.g., T2) by a predefined track distance (e.g., dt), and wherein the magnetization of the first track (e.g., T1) is substantially 180° phase-shifted from the magnetization of the second track (e.g., T2); and wherein the second plurality (e.g., N2) is equal to the first plurality (e.g., N1); wherein the sensor device is movable relative to the magnetic source along a predefined path or the magnetic source is movable relative to the sensor device along a predefined path, the position sensor system comprising: a magnetic source comprising a first plurality (e.g., N1) of alternating magnetic poles arranged along a first track, and comprising a second plurality (e.g., N2) of alternating magnetic poles arranged along a second track, wherein centers of the magnetic poles are separated by a predefined (e.g., linear or angular or circumferential) pole pitch (e.g., pp); wherein a centerline (e.g., C1) of the first track (e.g., T1) is separated from a centerline (e.g., C2) of the second track (e.g., T2) by a predefined track distance (e.g., dt); and wherein the magnetization of the first track (e.g., T1) is substantially 18 The sensor device includes a plurality of magnetic sensors along a predefined path spanning a distance less than 1.40 times the pole pitch (or spaced apart a distance less than 1.40 times the pole pitch); wherein the plurality of magnetic sensors are configured to measure a plurality of magnetic field components, the plurality of magnetic field components including a first magnetic field component (e.g., BxA, BzA) at a first sensor position (e.g., A) located above a first track (e.g., T1) but preferably not above a second track, and a second magnetic field component (e.g., BxB, BzB) parallel to the first magnetic field component at a second sensor position (e.g., B) located above a second track (e.g., T2) but preferably not above the first track; the sensor device is further configured to derive a plurality of difference signals (e.g., diff1, diff2) from the plurality of magnetic field components, and to derive the position from the plurality of difference signals (e.g., diff1, diff2).

[0014] The plurality of difference signals are preferably linearly independent of each other.

[0015] Or in other words: a first imaginary line passing through the first sensor element and oriented perpendicular to the surface (e.g., a planar or cylindrical surface) formed by the first and second rails intersects the first rail. Similarly, a second imaginary line passing through the second sensor element and oriented perpendicular to the surface intersects the second rail.

[0016] The “predefined path” may also be referred to as a “relative movement path”.

[0017] A major advantage of such a system is that the first and second difference signals, and therefore also the linear or angular position derived therefrom, are highly insensitive to external magnetic interference fields.

[0018] An advantage is that the first and second tracks are substantially 180° phase-shifted, as such magnets do not suffer from crosstalk between the tracks.

[0019] It is an advantage that the first sensor and the second sensor are located on the first track and the second track, since the signals are phase-shifted in a manner that is independent of the pole pitch (depending only on the track width).

[0020] In some embodiments where the first sensor signal and the second sensor signal are 180° phase shifted (see, e.g., Figures 4 to 8B as well as Figures 10 to 14B ), the difference between these signals provides approximately twice the signal amplitude (thus improving the signal-to-noise ratio) and cancels (or largely reduces) external interfering fields.

[0021] In an embodiment, the maximum distance between sensors along a predefined path (e.g., linear, angular, or circumferential distance) is less than 1.40 times the pole pitch, or less than 1.30 times the pole pitch, or less than 1.20 times the pole pitch, or less than 1.10 times the pole pitch, or less than 1.00 times the pole pitch, or less than 0.90 times the pole pitch, or less than 0.75 times the pole pitch, or less than 0.60 times the pole pitch, or less than 0.40 times the pole pitch.

[0022] In an embodiment, the maximum distance (e.g., linear, angular, or circumferential distance) between sensors along a predefined path is equal to approximately 1.00 times the pole pitch (±5%), or equal to approximately 0.67 times the pole pitch (±5%), or equal to approximately 0.50 times the pole pitch (±5%).

[0023] The predefined path may for example have a length of at least 5.0 mm or at least 10 mm.The path may for example be a straight line longer than 5 mm or longer than 10 mm, or a circular path with a radius greater than 3.0 mm or greater than 4.0 mm.

[0024] The position sensor system may be an angular position sensor system or a linear position sensor system.

[0025] In an embodiment, the number of north poles and south poles facing the sensor device is at least four north poles and four south poles, or at least six north poles and six south poles, or at least eight north poles and eight south poles, or at least ten north poles and ten south poles, or at least twelve north poles and twelve south poles, or at least sixteen north poles and sixteen south poles, or at least twenty north poles and twenty south poles.

[0026] Preferably, the first and second sensor positions (A, B) are located on a virtual line segment that is substantially perpendicular to the predefined path, for example on a line segment transverse to the direction of movement in the case of a linear position sensor system, or on a radially oriented line segment in the case of an angular position sensor system.

[0027] The second track may be adjacent to the first track. A groove may exist between the first track and the second track.

[0028] The magnetic poles of the first track (T1) have a predefined (linear or angular) pole pitch, and the magnetic poles of the second track (T2) have the same predefined pole pitch.

[0029] In an embodiment, the plurality of difference signals include at least one difference determined between a first signal measured at a first sensor position (e.g., A) above a first track (e.g., T1) and a second signal measured at a second sensor position (e.g., B) above a second track (e.g., T2).

[0030] In an embodiment, the predefined path is linear, and the first trajectory is linear, and the second trajectory is linear.

[0031] This type of position sensor system may be referred to as a "linear position sensor system."

[0032] The predefined path, the centerline of the first track and the centerline of the second track are preferably parallel to each other.

[0033] In an embodiment, each of the first and second tracks comprises at least two magnetic pole pairs (two facing upward and two facing downward), or at least three magnetic pole pairs, or at least four magnetic pole pairs, or at least five magnetic pole pairs, or at least six magnetic pole pairs (e.g., Figure 3 (pictured in the figure).

[0034] In an embodiment, the first track and the second track have a circular or annular shape with a common center, and the sensor device is located at a non-zero distance from said center.

[0035] Such a position sensor system may be referred to as an "angular position sensor system."

[0036] The predefined path, the center line of the first track and the center line of the second track are preferably located on concentric circles.

[0037] In an embodiment, each of the first and second rails includes at least four magnetic pole pairs (e.g., two north poles and two south poles on the top surface, and two north poles and two south poles on the bottom surface), or at least six magnetic pole pairs, or at least eight magnetic pole pairs (e.g., Figure 1), or at least ten or twelve or fourteen pole pairs, or at least sixteen pole pairs (e.g., as shown in FIG. Figure 2 (pictured in the figure).

[0038] In an embodiment, the magnetic source is rotatable about an axis of rotation, and the first and second orbits are concentric circular orbits lying in a single plane perpendicular to the axis of rotation.

[0039] In this embodiment, the magnetic source may be magnetized in the axial direction, ie the residual magnetic field may be parallel to the axis of rotation.The substrate of the sensor device may be oriented perpendicular to the axis of rotation.

[0040] In this embodiment, the first track T1 has a first circular centerline with a first radius, and the second track T2 has a second circular centerline with a second radius smaller than the first radius, and the difference between the first and second radii is equal to the predefined track distance "dt".

[0041] The sensor device is preferably mounted at a distance "above" the planar track in the range of 0.5 to 5.0 mm.

[0042] In an embodiment, the magnetic source is rotatable about a rotation axis, and the first track and the second track are cylindrical tracks about the rotation axis and are spaced apart in the axial direction of the rotation axis; wherein the first track has a first outer radius (e.g., R1) and the second track has a second outer radius (e.g., R2) equal to the first outer radius.

[0043] In this embodiment, the magnetic source may be magnetized in a radial direction, ie the residual magnetic field may be perpendicular to the axis of rotation.

[0044] The sensor device is preferably mounted "above" the cylindrical track at a distance in the range of 0.5 to 5.0 mm.

[0045] In an embodiment, the sensor device is further configured to measure a third magnetic field component (e.g., BzC) at a third sensor position (e.g., C), and to measure a fourth magnetic field component (e.g., BzD) at a fourth sensor position (e.g., BzD); wherein the first, second, third, and fourth are four different sensor positions; and wherein the third and fourth magnetic field components are oriented parallel to or orthogonal to the first magnetic field component (e.g., BzA); and wherein the plurality of difference signals include a first difference signal (e.g., diff1) and a second difference signal (e.g., diff2), wherein the first difference signal (e.g., diff1) is the difference between the first magnetic field component (e.g., BzA) and the second magnetic field component (e.g., BzB), and the second difference signal (diff2) is the difference between the third magnetic field component (e.g., BzC) and the fourth magnetic field component (e.g., BzD).

[0046] An example of this embodiment is Figures 4 to 7 in, and in Figures 11 to 13 is shown in .

[0047] It is an advantage if the first and second difference signals are also substantially 90° phase-shifted and if they have approximately the same amplitude, since in this case the linear position or the angular position can be easily calculated using the inverse tangent function. However, this is not absolutely necessary, since it is possible to scale the two difference signals so that they have the same amplitude and / or to use a so-called "modified inverse tangent function" if the two signals are not 90° phase-shifted.

[0048] In an embodiment, the first and second as well as the third and fourth magnetic field components are oriented parallel to the substrate (generally denoted: Bx)

[0049] In an embodiment, the first and second as well as the third and fourth magnetic field components are oriented perpendicular to the substrate (generally denoted: Bz)

[0050] In an embodiment, the first and second magnetic field components are oriented parallel to the substrate (generally denoted: Bx), and the third and fourth magnetic field components are oriented perpendicular to the substrate (generally denoted: Bz), e.g. Figure 14B shown.

[0051] In an embodiment, the sensor device comprises four horizontal Hall elements.

[0052] In an embodiment, the sensor device comprises four vertical Hall elements.

[0053] In an embodiment, the sensor device includes a substrate located at a predefined distance from a first track and a second track; and the first, second, third and fourth sensor positions are four different sensor positions (e.g., A, B, C, D); and the first, second, third and fourth magnetic field components (e.g., BzA, BzB, BzC, BzD) are oriented in a direction perpendicular to the substrate (e.g., Z).

[0054] An example of this embodiment is Figures 4 to 7 in, and in Figures 11 to 13 is shown in .

[0055] The substrate may be a semiconductor substrate.The sensor device may be packaged in a molded package and may have a plurality of leads (often referred to as a "semiconductor chip").

[0056] The magnetic sensor or magnetic sensor element may be incorporated in the substrate or may be mounted to the substrate.

[0057] In an embodiment, the semiconductor device includes only a single semiconductor substrate.

[0058] In an embodiment, the sensor device comprises four horizontal Hall elements, preferably not adjacent to an integrated magnetic flux concentrator (IMC).

[0059] In an embodiment, the sensor device includes a substrate located at a predefined distance from a first track and a second track; and the first, second, third and fourth sensor positions are four different sensor positions (e.g., A, B, C, D); and the first, second, third and fourth magnetic field components (e.g., BxA, BxB, BxC, BxD) are oriented in a direction parallel to the substrate (e.g., X) and tangential to the predefined path of relative movement.

[0060] An example of this embodiment is Figures 4 to 7 in, and in Figures 11 to 13 is shown in .

[0061] In an embodiment, the sensor device comprises four vertical Hall elements.

[0062] In an embodiment, a first sensor location (e.g., A) and a second sensor location (e.g., B) are located on a first line segment oriented substantially transverse to a predefined path; and a third sensor location (e.g., C) and a fourth sensor location (e.g., D) are located on a second line segment oriented orthogonal to the first line segment.

[0063] Such embodiments are Figures 4 to 6 In, and Figure 11 and Figure 12 is shown in the figure.

[0064] In an embodiment, a first sensor location (e.g., A) and a second sensor location (e.g., B) are located on a first line segment oriented substantially transverse to a predefined path; and a third sensor location (e.g., C) and a fourth sensor location (e.g., D) are located on a second line segment oriented substantially parallel to the first line segment.

[0065] Such embodiments are Figure 7 and Figure 13 is shown in the figure.

[0066] In an embodiment, the first and third sensor positions (A, C) are spaced substantially at 1 / 2 pole pitch, and similarly, the second and fourth sensor positions (B, D) are spaced substantially at 1 / 2 pole pitch. In this case, the inverse tangent formula of the ratio R, optionally multiplied by a constant K, can be used to determine the positions.

[0067] In an embodiment, the first and third sensor positions (A, C) are spaced apart by a distance in the range of 20% to 45% of the pole pitch, and similarly, the second and fourth sensor positions (B, D) are spaced apart by a distance in the range of 20% to 45% of the pole pitch. In this case, the inverse tangent formula [3] with a constant C different from 1.0 and / or with a constant T different from 0.0 can be used to determine the position.

[0068] In an embodiment, the first and third sensor positions (A, C) are spaced apart by a distance in the range of 55% to 80% of the pole pitch, and similarly, the second and fourth sensor positions (B, D) are spaced apart by a distance in the range of 55% to 80% of the pole pitch. In this case, the inverse tangent formula [3] with a constant C different from 1.0 and / or with a constant T different from 0.0 can be used to determine the position.

[0069] In an embodiment, the first line segment and the second line segment coincide, which means that the four sensor positions are four different sensor positions located on a single line, e.g. Figure 8B or Figure 14B As shown in the picture.

[0070] In an embodiment, the first segment and the second segment are spaced apart by at least 0.5 mm.

[0071] In an embodiment, the sensor device is further configured to measure a third magnetic field component (e.g., BxA) orthogonal to the first magnetic field component (e.g., BzA) at a first sensor position (e.g., A) or at a third sensor position (e.g., C) located on a virtual line passing through the first sensor position (e.g., A) and the second sensor position (e.g., B), and to measure a fourth magnetic field component (e.g., BxB) orthogonal to the second magnetic field component (e.g., BzB) at a second sensor position (e.g., B) or at a fourth sensor position (e.g., D) located on a virtual line passing through the first sensor position (e.g., A) and the second sensor position (e.g., B); and the plurality of difference signals include a first difference signal (e.g., diff1) and a second difference signal (e.g., diff2), wherein the first difference signal (e.g., diff1) is the difference between the first magnetic field component (e.g., BzA) and the second magnetic field component (e.g., BzB), and the second difference signal (e.g., diff2) is the difference between the third magnetic field component (e.g., BxA) and the fourth (e.g., BxB) magnetic field component.

[0072] An example of this embodiment is Figure 8A and Figure 14A is shown in .

[0073] The sensor device is preferably oriented such that an imaginary line segment [AB] interconnecting the first and second sensor positions (A, B) is oriented substantially perpendicular to the predefined path.

[0074] A major advantage of this embodiment is that there are only two sensor positions, the position of which is independent of the pole pitch, which means that a particular sensor chip can be used with a variety of different magnets.

[0075] In an embodiment, the sensor device includes two 2D sensors, a first 2D sensor located at a first sensor position (A) above a first track (T1), and a second 2D sensor located at a second sensor position (B) above a second track (T2). Each 2D sensor may include an integrated magnetic flux concentrator and two horizontal Hall elements, such as Figure 19 As shown in FIG, or may include a horizontal Hall element and at least one vertical Hall element, for example, as Figure 20 As shown in the figure.

[0076] In an embodiment, the plurality of difference signals include a first difference signal (eg, diff1) and a second difference signal (eg, diff2); and the position is determined as a function of a ratio of the first difference signal to the second difference signal (eg, an arctangent function).

[0077] In an embodiment, the position is determined according to or by using one of the following formulas: wherein diff1 is the first difference signal, diff2 is the second difference signal, R is the ratio of the first difference signal to the second difference signal, and K and M are predefined constants different from 1.0 (e.g., greater than 1.05 or less than 0.95); and wherein T is a predefined constant different from 0 (e.g., having an absolute value greater than at least 0.05).

[0078] The value of K may be different from 1.0 (e.g., may be less than 0.95 or greater than 1.05). The value of M may be equal to 1.0, or may be different from 1.0. For example, the value of M may be less than 0.95 or greater than 1.05. The value of T may be equal to 0.0, or may be different from 0.0 (e.g., the absolute value may be greater than 0.05). The values ​​of K, M, and T may be determined by simulation or by calibration and may be hard-coded or stored in non-volatile memory of the sensor device.

[0079] In the case of a linear position sensor system, the linear position can be calculated by multiplying the value of phi by a predefined constant related to the pole pitch (e.g., L).

[0080] In an embodiment, the sensor device is further configured to measure a third magnetic field component (e.g., BzC) parallel to the first magnetic field component (e.g., BzA) at a third sensor position (e.g., C); and the first and second sensor positions (e.g., A, B) are spaced apart by 1 / 3 pole pitch (such that the first and second signals are 240° phase-shifted because they are on different tracks), and wherein the first and third sensor positions (e.g., A, C) are spaced apart by 2 / 3 pole pitch (such that the first and third signals are 120° phase-shifted because they are on the same track); and wherein the sensor device is configured to: determine the first one, an average of the second, second and third magnetic field components (e.g., Bzavg); and for determining a first difference signal (e.g., diff1) as the difference between the first magnetic field component (e.g., BzA) and the average (e.g., Bzavg); and for determining a second difference signal (e.g., diff2) as the difference between the second magnetic field component (e.g., BzB) and the average (e.g., Bzavg); and for determining a third difference signal (e.g., diff3) as the difference between the third magnetic field component (e.g., BzC) and the average (e.g., Bzavg); and for determining a position based on the first, second and third difference signals.

[0081] An example of this embodiment is Figure 9 、 Figure 10 and Figure 5 is shown in .

[0082] The three difference signals are "three-phase signals," i.e., they have substantially the same amplitude and are substantially 120° phase-shifted. It is known how to calculate position based on the three-phase signals. In an embodiment, the three-phase signals are converted into quadrature signals I, Q using the well-known Clarke transform, and the position is determined as a function of the ratio of these quadrature signals (e.g., as the inverse tangent of the ratio).

[0083] The magnetic source may be or may include a permanent magnet. The permanent magnet may include ferrite, or a composite material such as FeNi or nickel-ferrite, or may include a plastic bonded magnet.

[0084] The magnetic source may comprise an isotropic material, or may comprise an anisotropic magnetic material.

[0085] In an embodiment, the magnetic material includes or consists essentially of ferrite, SmCo, FeNdB, or plastic bonded magnet or plastic bonded magnetic powder.

[0086] In an embodiment, the first track (e.g., T1) has a first width (e.g., w1) in the range from 1.0 to 3.0 mm, or in the range from 1.5 to 2.5 mm; and wherein the second track (e.g., T2) has a second width (e.g., w2) in the range from 1.0 to 3.0 mm, or in the range from 1.5 to 2.5 mm; and wherein the distance (e.g., ds) between the first sensor location (e.g., A) and the second sensor location (e.g., B) is a value in the range from 1.0 to 3.0 mm, or in the range from 1.5 to 2.5 mm.

[0087] In an embodiment, the position sensor system is an angular position sensor system, and the magnetic source is mounted to the shaft, and wherein the sensor device is configured to determine a first angular position of the shaft; and wherein the position sensor system further includes a dipole magnet mechanically connected (e.g., directly or indirectly (e.g., via a plurality of gears)) to the shaft, and further includes a second sensor device configured to determine a second angular position of the shaft; and wherein the position sensor system is further configured to combine the first angular position and the second angular position. An advantage is that the combined position is a highly accurate value over at least 360°.

[0088] In an embodiment, the plurality of magnetic sensors includes only Hall sensors.

[0089] In an embodiment, the plurality of magnetic sensors comprises only horizontal Hall sensors; or

[0090] In an embodiment, the plurality of magnetic sensors comprises only vertical Hall sensors; or

[0091] In an embodiment, the plurality of magnetic sensors includes at least one horizontal Hall sensor and at least one vertical Hall sensor.

[0092] In an embodiment, the distance (e.g., ds) between the first sensor position (e.g., A) and the second sensor position (e.g., B) is less than the sum of the width (e.g., w1) of the first track (e.g., T1) and the width (e.g., w2) of the second track (e.g., T2), or less than 80% of the sum, or less than 70% of the sum, or less than 60% of the sum, or less than 50% of the sum, or less than 40% of the sum.

[0093] In an embodiment, the distance (e.g., ds) between the first sensor position (e.g., A) and the second sensor position (e.g., B) is less than 2.00 times the track distance (e.g., dt), or less than 1.50 times the track distance (e.g., dt), or less than 1.25 times the track distance (e.g., dt), or less than 1.00 times the track distance (e.g., dt), or less than 0.90 times the track distance (e.g., dt).

[0094] According to a second aspect, the present invention also provides a position sensor device for use in a position sensor system according to the first aspect; the position sensor device includes a substrate; the substrate includes: a first magnetic sensor for measuring a first magnetic field component (e.g., BzA) at a first sensor position (e.g., A), and a second magnetic sensor for measuring a second magnetic field component (e.g., BzB) at a second sensor position (e.g., B), and a third magnetic sensor for measuring a third magnetic field component (e.g., BzC) at a third sensor position (e.g., C); wherein the first, second, and third magnetic field components are parallel and oriented in a direction parallel to (e.g., X) or perpendicular to (e.g., Z) the substrate; wherein the first, second, and third magnetic sensors are located at corners of a triangle having first magnetic fields of equal length. side and a second side, and having a third side that is at least 10% longer or at least 10% shorter than the first side and the second side; the position sensor device further includes a processing unit configured to determine an average (e.g., Bzavg) of the first, second, and third magnetic field components, and to determine a first difference signal (e.g., diff1) as the difference between the first magnetic field component and the average, and to determine a second difference signal (e.g., diff2) as the difference between the second magnetic field component and the average, and to determine a third difference signal (e.g., diff3) as the difference between the third magnetic field component and the average; and to convert the three difference signals into orthogonal signals (e.g., using a Clarke transform), and to calculate the angular position based on these orthogonal signals (e.g., using an inverse tangent function of the ratio of the orthogonal signals).

[0095] In a variant, the length of the third side is at least 20% longer than the first side and the second side, or at least 20% shorter than the first side and the second side.

[0096] In case three magnetic sensors are configured for measuring a magnetic field component parallel to the substrate (eg Bx), the magnetic sensors are preferably oriented so that their axis of maximum sensitivity is parallel to the third side.

[0097] According to a third aspect, the present invention also provides a magnetic source comprising: a first plurality (e.g., N1) of alternating magnetic poles arranged along a first track (e.g., T1); a second plurality (e.g., N2) of alternating magnetic poles arranged along a second track (e.g., T2); wherein a centerline (e.g., C1) of the first track (e.g., T1) is spaced from a centerline (e.g., C2) of the second track (e.g., T2) by a predefined track distance (e.g., dt); wherein the magnetization of the first track (e.g., T1) is substantially 180° phase-shifted from the magnetization of the second track (e.g., T2); and wherein the second plurality (e.g., N2) is equal to the first plurality (e.g., N1).

[0098] In an embodiment, the first track (e.g., T1) and the second track (e.g., T2) are circular tracks lying substantially within a plane; and wherein the first track (e.g., T1) and the second track (e.g., T2) are concentric tracks; and wherein the first track (e.g., T1) and the second track (e.g., T2) are magnetized in a direction perpendicular to the plane.

[0099] In an embodiment, the first track (e.g., T1) and the second track (e.g., T2) are positioned on a cylindrical surface; and wherein the first track (e.g., T1) and the second track (e.g., T2) are magnetized in a direction perpendicular to the cylindrical surface.

[0100] In an embodiment, the first track (e.g., T1) and the second track (e.g., T2) are linear tracks positioned substantially within a plane; and wherein the first track (e.g., T1) and the second track (e.g., T2) are magnetized in a direction perpendicular to the plane.

[0101] Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate, and not merely as explicitly set out in the claims.

[0102] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0103] Figure 1 An illustrative example of an angular position sensor system according to an embodiment of the present invention is shown.

[0104] Figure 2 An illustrative example of an angular position sensor system according to another embodiment of the present invention is shown.

[0105] Figure 3 An illustrative example of a linear position sensor system according to an embodiment of the present invention is shown.

[0106] Figures 4 to 10 Shows that the Figure 1 Various sensor arrangements used in the sensor device of the angular position sensor system are shown in FIG.

[0107] Figures 11 to 15 Shows that the Figure 2 In the sensor device of the angular position sensor system shown in FIG, or in Figure 3 Various sensor arrangements used in linear position sensor systems are shown in FIG.

[0108] Figure 16 A diagram with three simulated curves is shown; each curve shows the performance of a sensor device relative to a Figure 1 The angular error as a function of the angular position of the magnetic source for a position sensor system having a Figure 4 The three graphs show that the position sensor system has relatively high accuracy, but the angular error is somewhat sensitive to radial mounting offset.

[0109] Figure 17 A diagram with three simulated curves is shown; each curve shows the performance of a sensor device relative to a Figure 1 The angular error as a function of the angular position of the magnetic source for a position sensor system having a Figure 7 The three graphs show that the accuracy of the position sensor system is relatively high, but the angular error is somewhat sensitive to radial mounting offset.

[0110] Figure 18 A diagram with three simulated curves is shown; each curve shows the performance of a sensor device relative to a Figure 1 The angular error as a function of the angular position of the magnetic source for a position sensor system having a sensor arrangement as illustrated in Figure 8 is shown. The three graphs illustrate that the accuracy of the position sensor system is relatively high and that the angular error is more highly insensitive to radial mounting offsets.

[0111] Figure 19 Shows that the Figure 8A and Figure 14A Examples of sensor structures used in sensor arrangements.

[0112] Figure 20 Shows that the Figure 8A and Figure 14A An example of another sensor structure used in a sensor arrangement.

[0113] Figure 21 Shows that the Figures 1 to 3 A high-level block diagram of the sensor devices used in the system.

[0114] Figure 22 A block diagram of a position sensor system is shown. The position sensor system includes Figures 1 to 3 The illustrated position sensor system includes a magnetic source with dual tracks for determining a fine position and a classical position sensor system for determining a coarse signal, and further includes a processor (e.g., an ECU) for combining the fine and coarse signals into a high-accuracy absolute position.

[0115] These figures are schematic and non-limiting. In the figures, for illustrative purposes, the size of some elements may be exaggerated and not drawn to scale. Any reference numerals in the claims should not be construed as limiting the scope. The same reference numerals in different figures refer to the same or similar elements. DETAILED DESCRIPTION

[0116] The present invention will be described with respect to specific embodiments and with reference to certain drawings, but the invention is not limited thereto but only by the claims. The drawings described are merely schematic and non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. Dimensions and relative sizes do not correspond to actual reductions in practice of the invention.

[0117] Furthermore, the terms first, second, etc. in the specification and in the claims are used to distinguish between similar elements and are not necessarily used to describe a sequence in time, space, ranking, or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of operation in a sequence other than that described or illustrated herein.

[0118] Furthermore, the terms top, bottom, etc. in the description and claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of operation in orientations other than those described or illustrated herein.

[0119] It should be noted that the term "comprising" as used in the claims should not be interpreted as being limited to the means listed thereafter; it does not exclude other elements or steps. Thus, the term should be interpreted as specifying the presence of the stated features, integers, steps, or components as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to a device consisting solely of components A and B. It means that for the purposes of the present invention, the only relevant components of the device are A and B.

[0120] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may refer to different embodiments. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure.

[0121] Similarly, it should be appreciated that in the description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, this method of disclosure should not be interpreted 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, inventive aspects lie in fewer features than all of the features of a single preceding disclosed embodiment. Accordingly, the claims appended to the detailed description are hereby expressly incorporated into this detailed description, with each claim itself representing a separate embodiment of the present invention.

[0122] Furthermore, although some embodiments described herein include some features included in other embodiments but do not include other features included in those other embodiments, combinations of features from different embodiments are intended to fall within the scope of the present invention and form different embodiments as would be understood by those skilled in the art. For example, in the appended claims, any of the claimed embodiments may be used in any combination.

[0123] In the description provided herein, numerous specific details are set forth. However, it should be understood that embodiments of the present invention may be practiced without these specific details. In other instances, well-known methods, structures, and techniques are not shown in detail to avoid obscuring understanding of this description.

[0124] In this document, unless explicitly mentioned otherwise, the term "magnetic sensor device" or "sensor device" refers to a device comprising at least one "magnetic sensor" or at least one magnetic "sensor element," preferably integrated into a semiconductor substrate. The sensor device may be included in a package, also referred to as a "chip," although this is not absolutely necessary. The sensor device preferably comprises a semiconductor substrate.

[0125] In this document, the term “sensor element” or “magnetic sensor element” or “magnetic sensor” may refer to a component or a group of components or subcircuits or structures capable of measuring magnetic quantities, such as, for example, a magnetoresistive (MR) element, a GMR element, an XMR element, a horizontal Hall plate, a vertical Hall plate, a Wheatstone bridge comprising at least one (but preferably four) magnetoresistive elements, etc., or a combination thereof.

[0126] In certain embodiments of the present invention, the term "magnetic sensor" or "magnetic sensor structure" may refer to an arrangement including one or more integrated magnetic concentrators (IMCs) (also referred to as integrated flux concentrators), and one or more horizontal Hall elements arranged near the periphery of the IMC, such as a disk-shaped IMC having two horizontal Hall elements spaced 180° apart from each other (e.g., as in FIG. Figure 19 ), or an IMC with four horizontal Hall elements spaced 90° apart from each other (not shown).

[0127] In this document, the expressions "in-plane component of the magnetic field vector" and "projection of the magnetic field vector in the sensor plane" are used synonymously. If the sensor device is or includes a substrate, this also means "the magnetic field component parallel to the substrate."

[0128] In this document, the expressions “out-of-plane component of a vector” and “Z component of a vector” and “projection of the vector onto the axis perpendicular to the sensor plane” have the same meaning.

[0129] In this document, the words "magnet", "magnetic structure" and "magnetic source" are used as synonyms.

[0130] Embodiments of the present invention are generally described using an orthogonal coordinate system fixed to the sensor device and having three axes X, Y, and Z, wherein the X and Y axes are parallel to the substrate and the Z axis is perpendicular to the substrate. Furthermore, in the case of a linear position sensor system, the X axis is preferably oriented "parallel to the direction of relative movement" (e.g., as Figure 3 ), or in the case of a curved movement trajectory, oriented “tangentially to the movement trajectory” or oriented in the “circumferential direction”, i.e. in the case of an angular position sensor system comprising a rotatable magnet, tangentially to an imaginary circle having its center lying on the axis of rotation (e.g. as shown in FIG. Figure 1 or Figure 2 In the case of an angular position sensor system, one of the other axes (Y or Z) is preferably oriented parallel to the rotation axis of the magnet.

[0131] In this document, the expressions "spatial derivative" or "derivative" or "spatial gradient" or "gradient" are used as synonyms. In the context of the present invention, the gradient is usually determined as the difference between two values ​​measured at two locations spaced apart in the x-direction. In theory, the gradient is calculated as the difference between the two values ​​divided by the distance "dx" between the sensor locations, but in practice the division by "dx" is often omitted because the measured signal needs to be scaled anyway. Therefore, in the context of the present invention, the magnetic field difference (ΔBx) and the magnetic field gradient dBx / dx are used interchangeably.

[0132] In this document, the term "amplitude of the magnetic field component By" means "the maximum value of the absolute value of the By signal over the entire 360° (electrical) rotation range of the magnet", and the same applies to "amplitude of Bx" and "amplitude of Bz".

[0133] In this application, horizontal Hall plates are generally referred to as H1, H2, etc., and the signals from these horizontal Hall plates are generally referred to as h1, h2, etc.; vertical Hall plates are generally referred to as V1, V2, etc.; and the signals from these vertical Hall plates are generally referred to as v1, v2, etc.

[0134] In the context of the present invention, the formulas arctan(x / y), atan2(x,y), arccot(y / x) are considered equivalent.

[0135] In the present application, the expression "the sensor device is located at a certain axial and radial position" actually means that the center position of the sensor of the sensor device is located at the specified axial position and radial position.

[0136] In this application, the term "track" as part of the magnetic source, when talking about an angular position sensor system, generally refers to a ring-shaped or annular or cylindrical object, such as Figure 1 and Figure 2 , and usually refers to a beam-shaped object when talking about a linear position sensor system, such as Figure 3 As shown in the figure.

[0137] Figure 1 、 Figure 2 and Figure 3 The track of the magnetic source has a "width" extending in the radial direction R, the axial direction A and the transverse direction Y respectively.

[0138] As used herein, the term "track centerline" refers to an imaginary line or curve located in the middle of the track surface, width. Figure 1 In , the centerline is a circle having a radius equal to the average of the inner and outer radii of the corresponding track; in Figure 2 In , the centerline is a circle with a radius equal to the outer radius of the track and is located at half the width (in the axial direction); in Figure 3 In the case of a track, the centerline is the line running down the middle of the track (halfway across the track).

[0139] The expression "the tracks are spaced apart by a distance dt" as used herein means that the center lines of the tracks are spaced apart by said distance "dt".

[0140] The present invention relates to a linear position and angular position sensor system comprising a magnetic source and a sensor device movable relative to the magnetic source, and in particular to a position sensor system having high resolution (or high sensitivity) and high accuracy (or small error).

[0141] The present invention provides a position sensor system (e.g., a linear position or angular position sensor system) including a magnetic source and a sensor device. The sensor device is movable relative to the magnetic source, or the magnetic source is movable relative to the sensor device. The sensor device is configured to determine its position relative to the magnetic source.

[0142] According to a certain important aspect of the invention, the magnetic source comprises two adjacent tracks (e.g. two concentric tracks or two parallel tracks) having an equal number of magnetic poles, which are organized in such a way that "adjacent poles" of the two tracks have opposite polarity. Figure 1 This means that, for example, the magnetic south pole of the inner track T1 is at the same angular position It is adjacent to the magnetic north pole of the outer track T2. Figure 2 This means that, for example, the magnetic south pole of the upper track T1 is at the same angular position It is adjacent to the magnetic north pole of the lower track T2. Figure 3 In an arrangement of , this means that for example the magnetic south pole of the left track T1 is adjacent to the magnetic north pole of the right track T2 at the same linear position X.

[0143] The sensor device comprises a plurality of magnetic sensors configured to measure a plurality of magnetic field components, for example at least three magnetic field components (see for example Figure 9 、 Figure 10 、 Figure 15 ) or at least four magnetic field components (see e.g. Figure 4 to Figure 8, or Figure 11 to Figure 14). At least a first of these magnetic field components is measured at a first sensor position "A" facing, above, or outside of the first track T1, and at least a second of these magnetic field components is measured at a second sensor position "B" facing, above, or outside of the second track T2. The first and second magnetic field components are oriented parallel. Depending on the specific sensor configuration, the third and optional fourth magnetic field components may be measured above the first track T1 and / or above the second track T2, or the third component above the first track and the fourth component above the second track and their orientations may be the same as or different from the first magnetic field component.

[0144] The sensor device is further configured to derive (e.g. calculate) multiple (e.g., two or three) difference signals from the multiple magnetic field components, and to derive (e.g., calculate) the position from the multiple (e.g., two or three) difference signals.

[0145] More specifically, in some embodiments (see e.g. Figure 4 to Figure 8, or Figure 11 to Figure 1 4), the sensor device is further configured for measuring four magnetic field components, and for determining two paired difference signals, and for determining the position as a function of the ratio of these difference signals (e.g., an inverse tangent function). In other embodiments (see, e.g., Figure 9 、 Figure 10 、 Figure 15 ), the sensor device is configured to measure three parallel magnetic field components, and for determining an average of these three values, and for determining three pairwise differences between each of the three measured components and the average component, thereby obtaining a set of three-phase signals, and for applying a transformation (e.g., a Clarke transform) for converting the three-phase signals into orthogonal signals (typically represented as I and Q), and for determining the position as a function of the ratio of these orthogonal signals (e.g., an inverse tangent function).

[0146] A major advantage of such a system is that the first and second difference signals, and therefore also the linear or angular position derived therefrom, are highly insensitive to external magnetic interference fields.

[0147] An advantage is that the first and second tracks are substantially 180° phase-shifted, as such magnets do not suffer from crosstalk between the tracks.

[0148] An advantage is that the first and second sensors are located on the first and second tracks respectively because this allows their signals to be phase shifted by 180° without spacing the sensors by 1.0 pole pitch; or because this allows their signals to be phase shifted by 240° without spacing the sensors by 4 / 3 pole pitch.

[0149] In some embodiments where the first and second sensor signals are 180° phase shifted (see, e.g., Figures 4 to 8B as well as Figures 10 to 14B ), the difference between these signals provides approximately twice the signal amplitude (thus improving the signal-to-noise ratio) and cancels (or greatly reduces) external interfering fields.

[0150] Reference is now made to the drawings.

[0151] Figure 1 An illustrative example of an angular position sensor system 100 is shown. The system includes a magnetic source 102 and a sensor device 101 that is movable relative to the magnetic source, or vice versa. The magnetic source 102 includes two circular tracks T1 and T2 located within a plane. The first track T1 may also be referred to as the "inner track." The second track T2 may also be referred to as the "outer track." The first track T1 has a first width "w1." The second track T2 has a second width "w2." The first width w1 can be equal to the second width w2, but this is not strictly necessary.

[0152] The first track T1 and the second track T2 are adjacent tracks. The first track T1 has a first centerline c1, a portion of which is shown in dashed lines. The second track T2 has a second centerline c2. The first centerline c1 is a circle with a first radius, and the second centerline c2 is a concentric circle with a second radius. The distance "dt" between the two centerlines c1 and c2 is constant and is referred to as the "track distance."

[0153] Such a magnetic source 102 may be constructed, for example, by producing two axially magnetized ring magnets and subsequently mechanically joining them (eg, by gluing).

[0154] Another way of producing the magnetic source 102 is based on the use of relatively strong electric currents to magnetize the magnetic material (a technique known per se in the art, but not suitable for this particular topology).

[0155] Another way to produce the magnetic source 102 is by using a technique for making bonded magnets. This technique is also known per se, but is not suitable for this particular topology. Typically, a mixture containing magnetic particles, called a "feedstock," is injected into a mold cavity, and during molding, one or more permanent magnets are positioned near but outside the cavity.

[0156] In an embodiment, the magnetic source is made of, or entirely made of, an isotropic magnetic material. The material may be or include, for example, neodymium or ferrite, but other isotropic magnetic materials may also be used.

[0157] In an embodiment, the magnetic source is made of an anisotropic material.

[0158] In an embodiment, the magnetic source is made of SmCo or FeNdB.

[0159] As a specific example, the magnetic source 102 may have a Figure 1 The shape shown in FIG has an outer diameter (outer track) of 14.0 mm and an inner diameter (inner track) of 6.0 mm. The width w1, w2 of each track may be equal to 2.0 mm, and the thickness (or height) H may be 1.0 mm.

[0160] Each track may have, for example, 4 north poles and 4 south poles at its upper surface, whereby each track may have eight magnetic poles at its upper surface, each pole spanning an angular range of 360° / 8=45° (mechanical); or each track may have 12 magnetic poles at its upper surface, each pole spanning an angular range of 360° / 12=30° (mechanical); or each track may have 16 magnetic poles, each pole spanning an angular range of 360 / 16=22.5° (mechanical).

[0161] In a preferred embodiment, each track has at least four north poles and at least four south poles at its upper surface, or at least six north poles and at least six south poles at its upper surface, or at least eight north poles and at least eight south poles at its upper surface.

[0162] The sensor device 101 is configured for determining the angular position within this mechanical angular range.The higher the number of poles per track, the smaller the mechanical angular range and the more sensitive the magnetic positioning system 100 is.

[0163] The sensor device 102 includes a substrate having a plurality of magnetic sensors. The substrate may be a semiconductor substrate. The substrate may have a rectangular shape. The magnetic sensors may be arranged in various ways, for example, as will be shown in FIG. Figures 4 to 10 As described in more detail in .

[0164] The sensor device is configured to move at a predefined distance from the magnetic source in the range of 0.5 mm to 5.0 mm, or the magnetic source is configured to move at a predefined distance from the sensor device in the range of 0.5 mm to 5.0 mm. The path of relative movement of the sensor device 101 is a circular path having the same center as the magnetic source.

[0165] Figure 2An illustrative example of an angular position sensor system 200 is shown, which may be viewed as Figure 1 A variant of the position sensor system 100 has been developed. Figure 1 Most of the description of system 100 also applies here and will not be repeated. Figure 2 The angular position sensor system 200 and Figure 1 The main difference between the angular position sensor system 100 and the angular position sensor system 100 is that the tracks of the magnetic source 202 form a cylindrical surface. These tracks are preferably magnetized radially (in a direction perpendicular to the cylindrical surface). The sensor device 201 is arranged outside the cylindrical surface. This position can also be referred to as "on the equator". The sensor device 201 may include Figures 11 to 15 The sensor device 201 is preferably located at a fixed distance (commonly referred to as the "air gap") from the magnetic source 202 in the range of about 0.5 to about 5.0 mm.

[0166] Figure 3 An illustrative example of a linear position sensor system 300 is shown, which may be viewed as Figure 1 variant of the position sensor system 100 and is considered Figure 2 A variation of the position sensor system 200 . Figure 3 The linear position sensor system 300 with Figure 1 The main difference between the angular position sensor system 100 and the angular position sensor system 100 is that the tracks T1, T2 of the magnetic source 302 are two straight tracks located in a plane. These tracks are preferably magnetized in a direction Z perpendicular to the plane. The sensor device 301 is located above the plane and the path of relative movement is a straight line located in the X direction, indicated by the white arrow. The sensor device 301 may include Figures 11 to 15 The sensor device is preferably located at a fixed distance (commonly referred to as an "air gap") from the magnetic source 202 in the range of about 0.5 to about 5.0 mm.

[0167] Figures 4 to 10 Shows the Figure 1 Various sensor arrangements in the sensor device 101.

[0168] Figure 4 The diagram shows a sensor arrangement with four sensing points A, B, C, D, and also shows possible positions and / or orientations of these sensing points relative to the magnetic source. The four sensing points can be located at the corners of a diamond or at the corners of a square. Sensor device ( Figure 4 ) would include four magnetic sensors, one magnetic sensor at each of the sensor positions.

[0169] The sensor arrangement is preferably oriented such that the sensor positions A and B are located on an imaginary line which is oriented radially. The distance between the sensor positions A and B is not critical. It is sufficient that the first sensor position A is located above the first track T1 and the second sensor position B is located above the second track T2. Since the polarity of the first track T1 is opposite to the polarity of the second track T2, the signals of positions A and B are 180° phase-shifted, so that the difference between these signals essentially doubles the amplitude of the measured magnetic field component and essentially cancels out the constant external interference field. Positions A and B can be located on the center line of the tracks, but this is not absolutely necessary. If the distance between A and B is less than the track distance "dt" (see Figure 1 ), it is an advantage because it allows the size of the substrate to be reduced.

[0170] Sensor positions C and D are preferably both located above the first track T1 or both located above the second track T2. Ideally, sensor positions C and D are exactly 1.0 pole pitch apart from each other (indicated by the angle ψ), in which case the signals measured at positions C and D are substantially 180° (electrically) phase shifted. In this case, as Figure 4 The formula [1] or [2] shown can be used to calculate the angular position of the sensor device relative to the magnet. A first difference signal diff1 can be calculated between the signals obtained from the sensors located at A and B. The first difference signal diff1 behaves like a cosine. A second difference signal diff2 can be calculated between the signals obtained from the sensors located at C and D. The second difference signal diff2 behaves like a sine. If the amplitudes of diff1 and diff2 are substantially the same, formula [1] can be used. If the amplitudes of diff1 and diff2 are different, formula [2] can be used. The value of K is a constant that can be determined by simulation or by performing a calibration and can be stored in the non-volatile memory 2121 of the sensor device (see, for example Figure 21 ). The value of K may be chosen to be substantially equal to the ratio of the magnitude of diff1 to the magnitude of diff2.

[0171] However, there is no requirement that positions C and D be exactly 1.0 pole pitch apart from each other. If they are not separated by 1.0 pole pitch, then the angular positions The values ​​of M and T are constants that can be determined by simulation or by performing a calibration and can be stored in the non-volatile memory 2121 of the sensor device (see, for example, Figure 21 ).

[0172] Although not absolutely necessary, it is preferred that points C and D are located on an imaginary line segment CD that is perpendicular to the imaginary line segment AB.

[0173] In a specific embodiment (referred to as Example 4A), the sensor arrangement includes four horizontal Hall elements (not explicitly shown), one at each sensor location A, B, C, and D. The signals provided by these Hall elements indicate the magnetic field component Bz oriented in the Z direction at the corresponding location. By subtracting the signal provided by the sensor at A from the signal provided by the sensor at B, a first difference signal diff1 is obtained, which is proportional to (BzA-BzB) and behaves like a cosine signal. By subtracting the signal provided by the sensor at C from the signal provided by the sensor at D, a second difference signal diff2 is obtained, which is proportional to (BzC-BzD) and behaves like a sine signal.

[0174] In another embodiment (referred to as Example 4B), the sensor arrangement includes four vertical Hall elements (not explicitly shown), one at each sensor location A, B, C, and D, and oriented in the X direction with their axes of maximum sensitivity perpendicular to the line segment [AB]. The signals provided by these Hall elements indicate the magnetic field component Bx oriented in the X direction at the corresponding location. By subtracting the signal provided by the sensor at A from the signal provided by the sensor at B, a first difference signal diff1 is obtained, which is proportional to (BxA-BxB) and behaves like a cosine signal. By subtracting the signal provided by the sensor at C from the signal provided by the sensor at D, a second difference signal diff2 is obtained, which is proportional to (BxC-BxD) and behaves like a sine signal.

[0175] Note that the values ​​determined using formulas [1] to [3] The value is also called the "electrical angle". However, the mechanical angle corresponding to the electrical angle is only a part of the electrical angle. Figure 1 In the example of , the first track has 4 north poles and 4 south poles at its upper surface, and the mechanical angle Can be calculated as electrical angle Divide by 4.

[0176] Figure 16 Include the diagram as Figure 1 The magnetic source shown and using Figure 4 Simulation results of the sensor system with four horizontal Hall elements arranged as shown. Figure 16 It can be appreciated that the angular error of such a system (without post-processing) is very small (e.g., within ±0.05°) when the sensor device is mounted in its intended position, but the maximum angular error increases slightly (to approximately ±0.20°) when the sensor device is unintentionally offset by ±20 μm from its original mounting position.

[0177] Optionally, additional post-processing steps may be applied, for example, to further reduce the residual error. Such post-processing steps may, for example, include piecewise linear approximation correction or a lookup table, optionally with interpolation. Such post-processing techniques are known in the art and therefore need not be described in more detail herein.

[0178] In certain embodiments, the magnetic source has a Figure 1 , and each track has a width of 2.0 mm, whereby the center lines are spaced 2.0 mm apart. However, the distance between point A and point B can be a value less than or greater than the track distance. For example, the distance between point A and point B can be a value in the range of from 0.8 mm to 1.6 mm, or a value in the range of from 1.0 mm to 1.4 mm (e.g., approximately 1.2 mm). In certain embodiments, points A, B, C, and D are located at the corners of a square having a side length in the range of from about 0.5 mm to about 1.1 mm, or in the range of from about 0.6 mm to about 1.0 mm (e.g., approximately 0.8 mm).

[0179] Figure 5 A sensor arrangement 505 with four sensing points A, B, C, D is illustrated, and possible positions and / or orientations of these sensing points relative to a magnetic source are also shown. Figure 5 The sensor arrangement 505 can be viewed as Figure 4 A variation of the sensor arrangement 405 of FIG. 4 is shown in FIG. 4 , with the main difference being that points D, A, and C are located on a line segment perpendicular to line segment AB. Points D, C, and B are located at the corners of a triangle. Preferably, point A is located midway between points D and C. Figure 4 All other contents described apply mutatis mutandis here as well.

[0180] and Figure 4 The same formula as mentioned in [1] can also be used in this case. More specifically, in the case where the distance between sensor positions C and D is substantially equal to 1.0 pole pitch (indicated by the angle ψ), formula [1] can be used to determine the position of the sensor arrangement relative to the magnetic source. However, this is not absolutely necessary, and the distance between point C and point D can also be greater or less than 1.0 pole pitch, and formula [2] or formula [3] can be used instead.

[0181] When using Figure 5 The same advantages of high accuracy (or high sensitivity) and high robustness against external interference fields, against temperature changes, against aging effects and against demagnetization effects are also achieved when the sensor arrangement 505 is used.

[0182] Figure 6Another sensor arrangement 605 is illustrated with four sensing points A, B, C, D, and possible positions and / or orientations of these sensing points relative to a magnetic source. Figure 6 The sensor arrangement 605 can be viewed as Figure 5 A variation of the sensor arrangement 505 of FIG. 5 , the main difference being that points D, A, and C are located on a line segment perpendicular to line segment AB. Points D, C, and A are located at the corners of a triangle. Preferably, point B is located midway between points D and C. Figure 5 All other contents described apply mutatis mutandis. Figure 4 The same formula mentioned in the formula can also be used in this case.

[0183] When using Figure 6 The same advantages of high accuracy (or high sensitivity) and high robustness against external interference fields, against temperature changes, against aging effects and against demagnetization effects are also achieved when the sensor arrangement 605 is used.

[0184] Figure 5 and Figure 6 can be viewed as two extreme cases, where the imaginary line segment containing points C and D is drawn from the position containing point A ( Figure 5 to the left side of the point B ( Figure 6 ), but the present invention is not limited to this, and the line segment containing point C and point D can also assume an intermediate position, which means that line segment CD intersects line segment AB at a certain position between point A and point B.

[0185] Figure 7 Another sensor arrangement 705 is illustrated with four sensing points A, B, C, D, and possible positions and / or orientations of these sensing points relative to a magnetic source are shown. Figure 7 The sensor arrangement 705 can be viewed as Figure 5 A variant of the sensor arrangement 505, the main difference being Figure 5 Point C is now on the inner orbit instead of the outer orbit, but is located at a distance of 1 / 2 pole pitch from point B. In this case, the four points A, B, C, and D are located on the trapezoid, as shown in Figure 7 As shown in part (c) of Figure 5 All other contents described apply mutatis mutandis. Figure 4 The same formula as mentioned in the formula can also be used in this case, and the same advantages are achieved.

[0186] Figure 17 Include the diagram as Figure 1 The magnetic source shown and using Figure 7 Simulation results of the sensor system with four horizontal Hall elements arranged as shown. Figure 17 It can be appreciated that the angular error of such a system (without post-processing) is very small (e.g., within ±0.10°) when the sensor device is mounted in its intended position, but the maximum angular error increases slightly (to approximately ±0.20°) when the sensor device is unintentionally offset by ±20 μm from its original mounting position.

[0187] exist Figure 7 In the variant, the four points A, B, C, and D are located as follows Figure 7 (a) At the corners of the trapezoid or truncated triangle depicted. If the sensor device is displaced so that line segments CD and AB are oriented radially, then Figure 4 The same formulas presented in the formula can still be used, and similar results are expected.

[0188] exist Figure 7 In another variation, four points A, B, C, D are located on a rectangle (e.g., Figure 7 (depicted in part (b) of ). Figure 4 The same formulas as those presented in [1] can still be used, but the angular errors provided by formulas [1] to [3] may increase as the distance between A and D, and / or the distance between C and B deviate from 1 / 2 pole pitch. However, depending on the application, an error of about ±5° may still be allowed, especially considering that if each track includes 16 poles, the mechanical angle is, for example, 1 / 16. Note that this error can be reduced by applying post-processing steps (e.g., by using a lookup table with interpolation, and / or by using a piecewise linear approximation function).

[0189] Figure 8A The diagram shows a sensor arrangement with only two sensing points A and B, but at each sensing point two orthogonal magnetic field components are measured, namely one field component Bx oriented in the circumferential direction X (i.e. tangent to an imaginary circle passing through the sensing point) and one field component Bz oriented in the Z direction perpendicular to the surface of the magnetic source.

[0190] Figure 8A Possible locations of these sensing points relative to the magnetic source are also shown. The sensor arrangement is preferably oriented so that sensor locations A and B lie on an imaginary line that is oriented radially relative to the center of the magnetic source. The distance between sensor locations A and B is not critical. It is sufficient if one sensor location (e.g., A) is located above the outer rail and a second sensor location (e.g., B) is located above the inner rail.

[0191] Since the polarity of the first track T1 is opposite to that of the second track T2, the signals measured at positions A and B are 180° phase-shifted, so that the difference between these signals essentially doubles the amplitude of the measured magnetic field components Bx and Bz and essentially cancels out the constant external interference field. Positions A and B can be located on the center line of the tracks, but this is not absolutely necessary. If the distance between A and B is less than the track distance "dt" (see Figure 1 ), it is an advantage because it allows the size of the substrate to be reduced.

[0192] The sensor arrangement is configured for measuring the following at position A: a magnetic field component BxA oriented in the X direction and a magnetic field component BzA oriented in the Z direction, and for measuring the following at position B: a magnetic field component BxB oriented in the X direction and a magnetic field component BzB oriented in the Z direction. Such measurements can be made, for example, by using Figure 19 As shown in the figure, or as Figure 20 This is accomplished by the sensor structure shown in the figure, which will be explained further.

[0193] Return Reference Figure 8A By subtracting the signals BxA from BxB, a first difference signal diff1 that behaves like a cosine signal can be obtained, and by subtracting the signals BzA from BzB, a second difference signal diff2 that behaves like a sine signal can be obtained. If the amplitudes of the two difference signals are the same, then formula [1] can be applied to determine the angular position, i.e.: If the amplitudes of the difference signals are different, then formula [2] can be applied, i.e.: K is a predefined constant that can be determined by simulation or by performing a calibration test and which can be stored in a non-volatile memory of the sensor device (see e.g. Figure 21 ). In both cases, R = diff1 / diff2.

[0194] Figure 18 Include the diagram as Figure 1 The magnetic source shown and using Figure 19 The simulation results of the sensor system with the sensor arrangement shown are as follows: Figure 8A The magnetic sources are arranged as shown in FIG. Figure 18 It can be appreciated that the angular error of such a system (without post-processing) is very small (e.g., within ±0.02°) when the sensor device is mounted in its intended position, but the angular error of such a system (without post-processing) is also very small when the sensor device is unintentionally deviated from its original mounting position by ±20 μm, likely because the signals Bx and Bz are phase-shifted by 90° when measured at the same position and are independent of the pole pitch.

[0195] Although additional post-processing steps may also be applied in this case, for most applications this can usually be omitted.

[0196] The main advantage of this embodiment is that the sensor device can be highly compact, since it only requires two sensor positions and the distance between them is highly independent of the size of the magnetic source, not only the pole pitch, but also the track width, since, as mentioned above, it is sufficient that point A is located above the outer track and point B is located above the inner track, and since neither of them needs to be located on the center line of the track.

[0197] Figure 8B The diagram shows a sensor arrangement 805b with four different sensing points A, B, C, D located on a straight line, and wherein two of the sensing points are located on a first track and the other two sensing points are located on a second track. Figure 8B The sensor arrangement 805b can be viewed as Figure 8A A variant of the sensor arrangement 805a in the sense that in both arrangements two magnetic field components Bx and two magnetic field components Bz are measured, but in Figure 8A In the case of , the Bz component is measured at the same sensor location as the Bx component, while Figure 8B In this case, the four magnetic field components are measured at four different locations. Figure 8A The same formula as the formula mentioned in can also be used and the same advantages are achieved. Preferably, the arrangement of the sensor positions is symmetrical with respect to the transition between the first track and the second track, but this is not absolutely necessary. As already mentioned above, if the amplitudes of the difference signals diff1, diff2 are the same, then formula [1] can be used, and if the amplitude of diff1 is different from the amplitude of diff2, then formula [2] can be used. Figure 20 A slightly different sensor arrangement than the one shown in FIG (where, for example, two vertical Hall elements are located between two horizontal Hall elements, or two horizontal Hall elements are located between two vertical Hall elements) can be used in this case. The distances between the four sensor positions are not critical, but the two inner sensor positions ( Figure 14B The distance between the two external sensor locations ( Figure 14B At least 50%, preferably at least 60%, or at least 70%, or at least 80%, or at least 90% of the distance between A and B).

[0198] In an embodiment, Bx is measured at A and B, and Bz is measured at C and D.

[0199] In another embodiment, Bz is measured at A and B, and Bx is measured at C and D.

[0200] In another embodiment, Bx is measured at A and D, and Bz is measured at C and B.

[0201] In another embodiment, Bx is measured at C and B, and Bz is measured at A and D.

[0202] Figure 9 A sensor arrangement 905 is illustrated with only three sensing points A, B and C. At each sensing point one magnetic field component is measured, for example Bz oriented in the Z direction perpendicular to the substrate of the sensor device and perpendicular to the surface of the magnetic source. Figure 9 Possible locations of these sensing points relative to the magnetic source are also shown.

[0203] like Figure 9 As can be seen in FIG, one sensor location (eg, C) is located over one track, and another sensor location (eg, A and B) is located over the other track.

[0204] Preferably, the three sensor locations are located on an isosceles triangle. The isosceles triangle may be an equilateral triangle, but that is not necessary, and in a preferred embodiment, the isosceles triangle is not an equilateral triangle. Preferably, one of the sides (in Figure 9 In the example shown in , the length of side AB is at least 10% shorter or at least 10% longer than the other sides.

[0205] In a preferred embodiment, the distance between sensing points B and C is less than the track distance "dt." In a specific example, the track width w1 of the first track and the track width w2 of the second track are equal to 2.0 mm, and the distance between positions B and C is a value in the range of from 0.5 to 1.8 mm, or a value in the range of from 0.6 to 1.6 mm, or a value in the range of from 0.7 to 1.4 mm (e.g., equal to about 0.8 mm, or equal to about 1.0 mm, or equal to about 1.2 mm).

[0206] Preferably, sensing points A and C are angularly spaced at 1 / 3 of the pole pitch (indicated by angle ω), and preferably, sensing points C and B are angularly spaced at 1 / 3 of the pole pitch, and preferably, sensing points A and B are angularly spaced at 2 / 3 of the pole pitch (indicated by angle ψ), so that the signals BzA, BzB, BzC measured at these positions are 120° phase-shifted. Thus, in the absence of an external interfering field, the measured signals are three-phase signals. Techniques for calculating the angular position of three-phase signals are known in the art, and any such technique can be used to determine the angular position of the sensor device relative to the magnetic structure. For the sake of completeness, one such technique will be explained here.

[0207] In an embodiment, the average of the magnetic field components BzA, BzB, BzC is calculated, for example, according to the following formula:

[0208] Bzavg=(BzA+BzB+BzC) / 3

[0209] Here, Bzavg is the average Bz component, and BzA, BzB, BzC are the magnetic field components oriented in the Z direction measured at positions A, B, C, respectively.

[0210] Ideally, in the absence of external interfering fields, this average Bzavg should be equal to zero. In practice, the average will not be exactly equal to zero, for example, due to one or more of the following:

[0211] Installation tolerances, magnetic source defects, external interference fields, etc.

[0212] From the measured signal and from the average signal, three difference signals can be derived, for example, according to the following formulas:

[0213] diff1=(BzA-Bzavg)

[0214] diff2=(BzB-Bzavg)

[0215] diff3=(BzC-Bzavg)

[0216] Each of these difference signals behaves like a sinusoidal signal with a DC value of approximately zero. These difference signals are 120° phase-shifted relative to each other and together they form a three-phase signal. This three-phase signal can be converted into a two-phase signal using known techniques (e.g. using the well-known Clarke transformation), resulting in two signals, referred to as I and Q. These signals are 90° phase-shifted and, ideally, have the same amplitude. Optionally, an amplitude correction can be applied to the three-phase signal, or to the two-phase signal. The angular position of the sensor device relative to the magnetic source is then It can be calculated, for example, as a function of the ratio R of the signals I to Q according to the following formula:

[0217] R=Q / I,

[0218]

[0219] As mentioned above, optionally, a post-processing step may be applied to further improve the results. Such a post-processing step may include the use of a lookup table (optionally with interpolation), or may include the use of a piecewise linear approximation function.

[0220] The main advantage is that such a sensor arrangement can be highly compact and the influence of external interference fields can be greatly reduced or even completely eliminated.

[0221] Note that a particular sensor device of particular dimensions may be used in conjunction with various magnetic sources having slightly varying numbers of poles and / or slightly varying pole pitches and / or slightly varying track widths and / or slightly varying inner and outer diameters. In practice, by shifting the sensor device radially inwards or outwards, it may be ensured that the distance between sensor positions A and B is substantially equal to 2 / 3 of the pole pitch. This radial displacement may have some effect on the amplitude of the signals measured at A, B, C, but any amplitude variations may be corrected in a known manner, for example, by multiplying the measured signals by a corresponding predefined constant, which constant may be determined by simulation or by calibration and may be stored in the non-volatile memory 2121 of the sensor device (see, e.g. Figure 21 ).

[0222] In a variant of the sensor arrangement described above, the sensor device is configured to measure three magnetic field components BxA, BxB, BxC oriented parallel to the substrate (e.g. in the X direction) at sensor positions A, B, C, respectively. The X direction is parallel to the line segment AB. In an embodiment, the sensor device comprises three vertical Hall elements located on an isosceles triangle having three angles A, B, C and having three sides [AB], [BC] and [CA]. The length of side [AB] may be at least 10% shorter or at least 10% longer than each of the length of side [AC] and the length of side [BC]. For Figure 9 Everything else described applies here mutatis mutandis.In another embodiment, the sensor device comprises at least three magneto-resistive (MR) elements configured for measuring three magnetic field components BxA, BxB, BxC.

[0223] Figure 10 The diagram shows what can be considered Figure 9 The sensor arrangement 1005 is a variant of the sensor arrangement 905. The main difference is that in this case one of the sensor points (e.g. A) is located on the outer rail and the other two sensor points (e.g. B and C) are located on the inner rail. The main advantage is that Figure 10 The sensor arrangement shown can be even more precise than a sensor device with Figure 9 The sensor arrangement of the sensor device is more compact because Figure 10 The distance between point B and point C in can be less than Figure 9 The distance between points A and B is reduced while still being angularly spaced at 2 / 3 the pole pitch (corresponding to a 120° phase shift). Figure 9Everything else described applies here as well.

[0224] In an embodiment, the sensor arrangement 1005 comprises three horizontal Hall elements for measuring BzA, BzB, BzC at sensor positions A, B, C.

[0225] In a variant, the sensor arrangement 1005 comprises three perpendicular Hall elements oriented with their maximum sensitivity axes in the X direction, configured for measuring three magnetic field components BxA, BxB, BxC at sensor positions A, B, C, respectively.

[0226] In another variant, the sensor arrangement 1005 comprises at least three magnetoresistive (MR) elements configured for measuring three magnetic field components BxA, BxB, BxC at sensor positions A, B, C, respectively.

[0227] Technical readers will understand that Figure 9 The configuration shown in the figure and Figure 10 The configuration illustrated in FIG, although with slightly different magnet size and / or pole pitch, can be obtained simply by rotating the sensor device 180° around the Z axis. Or in other words, this means having a specific size and having Figure 9 or Figure 10 The particular sensor device of the sensor arrangement illustrated in can be used with magnetic sources having various sizes and / or pole pitches.

[0228] Figures 11 to 15 Various sensor arrangements are shown, which can be Figure 2 and Figure 3 The sensor devices 201, 301 of the systems 200, 300 shown in FIG. Figures 4 to 10 The sensor arrangement can be used with Figure 1 102 is used in conjunction with the magnetic source 102 shown in FIG. 10 to form the angular position sensor system 100. Many of these sensor arrangements can also be used with Figure 2 202 to form an angular position sensor system 200, or with a magnetic source 202 as shown in FIG. Figure 3 302 are used in conjunction with the magnetic source 302 shown in FIG to form a linear position sensor system 300. An example of such an arrangement will now be described. Figures 11 to 15 is illustrated in more detail in .

[0229] Figure 11 A sensor arrangement 1105 is shown, which includes Figure 4 The four sensor positions in the above are similar or identical to the four sensor positions A, B, C, and D. Figure 4 Everything described for the sensor arrangement 405 applies mutatis mutandis here, meaning that, for example, Figure 11The two tracks of are straight rather than circular, and the line segment AB is oriented in the transverse direction rather than in the radial direction.

[0230] and Figure 4 The same formula as presented in applies here. Preferably, the distance between point C and point D is equal to 1.0 times the pole pitch, but Figures 4 to 10 In contrast to the arrangement shown in Figure 11 The pole pitch of the magnetic source shown in is fixed and cannot be increased or decreased by shifting the sensor device in the transverse direction Y. Figure 2 In the case of an angular sensor system 200 in which the sensor device 201 is mounted "at the equator", the pole pitch seen by the sensor device may be slightly increased or decreased with the varying air gap. However, as already described above, this can be resolved by using formula [2] or formula [3] instead of formula [1].

[0231] Furthermore, in the case of linear position sensor systems (e.g. Figure 3 shown), angle For example, by changing the angle Multiplication by a constant L is usually converted into a linear distance X, for example, according to the following formula: Where X is the linear position and L is a predefined constant. The value of L can be determined as the pole pitch (expressed in mm) divided by π (pi = about 3.1416). To obtain the absolute position, integer (n) multiples of the pole pitch can be added in a manner known per se in the art. This can be written mathematically as: where pp is the pole-to-pole distance. The value of "n" can be determined dynamically (e.g. by counting, starting from a reference position) or can be determined using a second sensor system mechanically coupled to the first sensor system (see also Figure 22 ).

[0232] like Figure 4 In the case of FIG, the sensor arrangement 1105 may include four horizontal Hall elements for measuring BzA to BzD, or may include four vertical Hall elements for measuring BxA to BxD, or may include four MR elements for measuring BxA to BxD.

[0233] Considering that only one of the curves will be applicable, namely the curve corresponding to the pole pitch versus the distance between sensor points C and D, Figure 16 The simulation results also apply to Figure 11 But as explained above, any mismatch can be corrected to a large extent by using Equation [2] or Equation [3].

[0234] Figure 12 Shown includes with Figure 5 or Figure 6 The four sensor positions A, B, C, and D are arranged in a similar manner to the sensor arrangement 1205. Figure 12 The sensor arrangement 1205 can also be viewed as Figure 11 A variation of the sensor arrangement 1105 in which sensor points C and D are displaced laterally toward point A. Figure 5 All other contents described and variations thereof, or Figure 6 and its variants, or Figure 11 and variations thereof apply mutatis mutandis.

[0235] Figure 13 Shown includes with Figure 7 The sensor arrangement 1305 of the four sensor positions A, B, C, D is arranged in a similar manner to the sensor arrangement 705 in FIG. 7 (particularly in part (b) of FIG. 7 ). Figure 13 The sensor arrangement 1305 can also be viewed as Figure 11 A variation of the sensor arrangement 1105 in which sensor points C and D are shifted. Figure 7 All other contents described and variations thereof, or Figure 11 and variations thereof apply mutatis mutandis.

[0236] Considering that only one of the curves will be applicable, namely the curve corresponding to the pole pitch versus the distance between sensor points A and C (and between B and D), Figure 17 The simulation results also apply to Figure 13 But as explained above, any mismatch can be corrected to a large extent by using Equation [2] or Equation [3].

[0237] Figure 14A Shown are only the Figure 8A The sensor arrangement 1405 is a sensor arrangement of two sensor positions A and B arranged in a similar manner to the sensor arrangement 805. At each sensor position two magnetic field components are measured: Bx oriented in the X direction, and Bz oriented in the Z direction. Figure 14A The formula shown is applicable. Figure 19 or Figure 20 A sensor structure of φ may be used, but of course, other sensor structures capable of measuring Bx and Bz at two positions A, B spaced apart in the Y direction may also be used.

[0238] and Figure 8A Similar to the case of , the sensors need not be located exactly in the middle of the track, but may be spaced apart by a distance "ds" that is less than or greater than the track distance "dt".

[0239] In an illustrative example, the width w1 of the first track and the width w2 of the second track are 2.0 mm, so the distance "dt" between the center line and the track is also equal to 2.0 mm. However, preferably, the distance "ds" between the sensor positions A and B is less than the track distance "dt". For example, "ds" can be a value within the range from 0.5 mm to 1.8 mm, or a value within the range from 0.6 mm to 1.6 mm (e.g., equal to approximately 0.8 mm, or equal to approximately 1.0 mm, or equal to approximately 1.2 mm, or equal to approximately 1.4 mm). By choosing (ds < dt), for example, ds is 20% to 90% of dt, the size of the substrate of the sensor device can be reduced.

[0240] The main advantage of this embodiment is that the sensor device only requires two sensor positions, and in addition, these two sensor positions can be positioned relatively closely together, especially at the distance "ds", which is largely independent of the track distance "dt" and independent of the pole pitch "pp".

[0241] Considering that only one of the curves in a single curve will be applicable, Figure 18 The simulation results depending on the lateral shift (in the Y direction) are also applicable to the structure of FIG. 14.

[0242] Figure 14B The figure shows a sensor arrangement 1405b having four different sensing points A, B, C, D located on a straight line, and among them, two of the sensing points are located on the first track, and the other two sensing points are located on the second track. Figure 14B The sensor arrangement 1405b can be regarded as Figure 8A a variant of the sensor arrangement 805a, and Figure 14A a variant of the sensor arrangement 1405a.

[0243] Figure 15 It shows a sensor arrangement 1505 including only three sensor positions A, B, C, and this sensor arrangement 1505 is arranged in a similar manner to Figure 9 or Figure 10 the sensor arrangement. Figure 15 The sensor arrangement 1505 can also be regarded as Figure 11 a variant of the sensor arrangement 1105. The sensor arrangement 1505 only has three sensor positions, where A and B, and B and C are spaced apart by 1 / 3 pole pitch, so A and C are spaced apart by 2 / 3 pole pitch. The same formula as provided in Figure 9 is also applicable here.

[0244] Figure 16 It shows the use of a commercial software simulation program A graph with three simulation curves was obtained. Each curve graph shows Figure 1 The angular error as a function of the angular position of the sensor device of the position sensor system 100 is shown. The position sensor system 100 includes:

[0245] like Figure 1 The shaped magnetic source 102 shown in FIG has an inner diameter of 6.0 mm and an outer diameter of 14.0 mm. The magnetic source is magnetized axially (in the Z direction) and has two adjacent tracks, each track having a width of 2.0 mm, each track having 16 equally spaced north poles and 16 south poles on its upper surface (facing the sensor device), each pole having a pole pitch of 360° / 32=11.25°. The magnetic source material can be or include alloy powder core ferrite with a magnetization of 220 kA / m;

[0246] And with Figure 4 The sensor device 101 of the sensor arrangement 405 illustrated in the figure comprises four horizontal Hall elements (or four pairs of horizontal Hall elements connected in parallel or in series for improving the signal-to-noise ratio) configured to measure Bz components BzA, BzB, BzC, BzD at four positions A, B, C, D located at the corners of a virtual square having a diagonal of 1200 μm (and thus having four sides of approximately 849 μm) and at an air gap of approximately 0.5 mm above the track.

[0247] Each curve shows the mechanical angular position of the magnetic source 102 relative to the sensor device 101 when using formula [1] The simulated angular error (in degrees) of the function .

[0248] The curve with black circles shows the simulated angular error (in degrees) when the sensor device is mounted so that points B and D are located on an imaginary circle with a radius of 3.0 mm (6.0 mm / 2 inner diameter) + 2.0 (inner track width) + 0.35 mm (radially outward, toward the outer track centerline) = 5.35 mm. In this position (referred to as the "reference position" or "imaginary position"), the difference signals diff1 and diff2 have the same amplitude and are therefore orthogonal signals.

[0249] The curve with black squares shows the simulated angular error in the case where the sensor device is mounted 20 μm radially inwards relative to the “reference position”.

[0250] The curve with black triangles shows the simulated angular error in the case where the sensor device is mounted at a position 20 μm radially outwards relative to the “reference position”.

[0251] Taking into account that the angular error of a classic angular position sensor system using a bipolar ring magnet with identical inner and outer diameters is approximately ±0.3° (over the envisaged temperature range and external influences), and assuming a mounting error of less than ±20 μm, it can be understood that the solution proposed by the present invention is more accurate than existing systems.

[0252] Figure 17 A graph with three simulation curves is shown, indicating that Figure 1 The angular errors of the position sensor system 100 shown include those for Figure 16 The same magnetic source as described, but including a Figure 7 The sensor device of four horizontal Hall elements arranged on the rectangle illustrated in part (b) has a distance [AB]=[CD]=1200 μm and a distance [AD]=[BC]=849 μm. Figure 17 The error of the curve is Figure 16 The error of the curve is quite large.

[0253] Figure 18 A graph is shown with three simulation curves representing the Figure 1 The angular error of the position sensor system 100 shown in FIG. Figure 16 The same magnetic source as described, but comprising a sensor device with a sensor arrangement with two so-called "2D magnetic pixels" arranged at points A and B as illustrated in FIG8 . This can be done, for example, using Figure 19 or as Figure 20 This is achieved by the sensor device shown in FIG. Figure 18 The simulation targets Figure 19 A sensor structure is implemented, where each sensor includes an integrated magnetic concentrator (IMC) disk having a diameter of approximately 190 μm, and two horizontal Hall elements arranged on opposite sides of the IMC disk. Figure 18 In the simulation, the two sensor positions A, B are located on the center line of the track and are therefore spaced apart by a distance ds = 2.0 mm in the Y direction.

[0254] The curve with black circles shows the simulated angular error (in degrees) when the sensor is installed in a reference position (where the spacing of sensor point A from the outer radius is equal to the spacing of sensor point B from the inner radius). As can be seen, the maximum error is less than approximately ±0.03°, which is approximately a factor of 10 improvement compared to the prior art.

[0255] The curve with black squares shows the simulated angular error when the sensor device is mounted 20 μm radially inward relative to the reference position. The curve with black triangles shows the simulated angular error when the sensor device is mounted 20 μm radially outward relative to the reference position. As can be seen, the error remains more or less the same.

[0256] In addition to the advantages mentioned above (high robustness to aging, temperature effects and external interference fields), Figure 8A and Figure 8B The sensor arrangement of also offers the advantages that the dimensions of the sensor device are independent of the pole pitch and largely independent of the track width, and (last but not least) the errors are highly independent of the radial mounting position. It was found that the errors are also highly independent of the radial mounting position (i.e. the displacement in the X direction), so that with Figure 8A or Figure 8B The installation requirements for the sensor equipment of the sensor arrangement illustrated in can be seriously relaxed.

[0257] It should be pointed out that Figures 6 to 18 The simulation also indicates Figure 2 The angular position sensor system 200 has the following features: Figures 4 to 10 The accuracy of the sensor device 201 combination of the sensor arrangement illustrated in Figure 3 The linear position sensor system 300 is provided with Figures 11 to 15 The accuracy of the sensor device 301 combination of the sensor arrangement illustrated in FIG.

[0258] As far as the inventor knows, Figures 1 to 3 The magnetic source illustrated in FIG is not known in the art.

[0259] Sensor devices having three or four horizontal Hall elements or having three or four vertical Hall elements or having three or four magnetoresistive elements for measuring three or four parallel-oriented magnetic field components at three or four sensor positions are known in the art and therefore do not need to be described in more detail here.

[0260] However, Figure 8A and Figure 14A The sensor arrangement includes two 2D magnetic pixels and may require more explanation. Two possible embodiments are provided below, but the present invention is not limited thereto, and other sensor structures capable of measuring two orthogonal magnetic field components (e.g., Bx parallel to the substrate and Bz perpendicular to the substrate) at two different locations spaced apart in the Y direction may also be used.

[0261] Figure 19 Shows that it can be Figure 8A and14A Examples of sensor structures used in sensor arrangements. Figure 19 The sensor structure includes two sensors S1 and S2. Each sensor is a "2D magnetic pixel" and includes an integrated magnetic concentrator (IMC) and two horizontal Hall elements arranged at the periphery of the IMC disk. It can be seen that the IMC disks are spaced apart in the Y direction, and the two horizontal Hall elements are spaced apart in the X direction. In the envisioned application, the distance "ds" between the centers of the IMC disks can be a value in the range from 500μm to 3000μm, but preferably, it is a value in the range from 600μm to 2500μm, or a value in the range from 600μm to 2000μm, or a value in the range from 700μm to 1600μm. Assuming that the signals provided by the Hall elements H1, H2, H3, H4 are called h1, h2, h3, h4 respectively, the Bz component measured by the first sensor S1 is proportional to (h1+h2), the Bx component measured by the first sensor S1 is proportional to (h1-h2), the Bz component measured by the second sensor S2 is proportional to (h3+h4), and the Bx component measured by the second sensor S2 is proportional to (h3-h4). If we abstract the signal scaling (which we need to do anyway), we can write Bz1=(h1+h2), Bx1=(h1-h2), Bz2=(h3+h4), and Bx2=(h3h4). In Figure 8A and Figure 14A In the arrangement, the first difference ΔBx between the Bx1 and Bx2 components is calculated, and the second difference ΔBz between the Bz1 and Bz2 components is calculated. Figure 8A and Figure 14A As mentioned in , the angular (and optionally linear) position can be derived from the ratio of these difference signals.

[0262] exist Figure 19 In a variant (not explicitly shown), instead of four individual Hall elements H1, H2, H3, H4, four pairs of two adjacent Hall elements connected in parallel or in series may be used. The first pair would comprise a Hall element located substantially parallel to the Hall element. Figure 19 The second pair will contain two horizontal Hall elements located substantially at the same position as H1. Figure 19 The two horizontal Hall elements of H2 are at the same position, and so on. By doing so, the signal-to-noise ratio of the measured magnetic field component can be improved.

[0263] Figure 20 Shows that the Figure 8A and Figure 14A An example of another sensor structure used in a sensor arrangement. Figure 20The sensor structure includes two sensors S1 and S2 spaced apart in the Y direction. Each sensor includes a horizontal Hall element (e.g., H1) and a vertical Hall element (e.g., V1) oriented with its axis of maximum sensitivity in the X direction. In the envisioned application, the distance "ds" between the centers of the horizontal Hall elements can be a value in the range from 500μm to 3000μm, but preferably, a value in the range from 600μm to 2500μm, or a value in the range from 600μm to 2000μm, or a value in the range from 700μm to 1600μm. Assuming that the signals provided by the Hall elements H1, H2 are referred to as h1, h2, and the signals provided by the vertical Hall elements V1, V2 are referred to as v1, v2, and abstracting for scaling, the Bx and Bz components measured by the first sensor S1 can be written as Bx1=v1; Bz1=h1. Likewise, the Bx and Bz components measured by the second sensor S2 can be written as Bx2=v2; Bz2=h2. From these signals, two difference signals ΔBx, ΔBz can be determined, and the angular (and optionally, linear) position can be derived from the ratio of these difference signals.

[0264] exist Figure 20 In a variation (not explicitly shown), each of sensors S1 and S2 includes two vertical Hall elements (instead of just one), located on opposite sides of the Hall element. In other words, in this embodiment, the horizontal Hall element is located between the two vertical Hall elements, and the signals obtained from the two vertical Hall elements are added or averaged. In this way, a more accurate value for Bx can be obtained.

[0265] In another variant (ref. Figure 8B and Figure 14B In another embodiment, the two vertical Hall plates may be external sensor elements, separated by a distance "ds", and the two horizontal Hall plates may be located between the two vertical Hall plates. Other variations are also possible.

[0266] Figure 21 A high-level block diagram of a sensor device 2120 that may be used in embodiments of the present invention is shown. For completeness, a brief description of possible hardware is provided here.

[0267] The position sensor device 2120 includes a plurality of magnetic sensor elements SE1 to SE3 (e.g., Figure 9 The three horizontal Hall elements arranged as shown in FIG, or Figure 4 The four horizontal Hall elements arranged as shown in FIG, or Figure 20 , and so on. Although not explicitly shown, the sensor device 2120 typically also includes bias circuitry, readout circuitry, one or more amplifiers, an analog-to-digital converter (ADC), etc. Such circuitry is well known in the art and is not the primary focus of the present invention.

[0268] The position sensor device 2120 further comprises a processing circuit 2122, e.g., a programmable processing unit, configured to receive the signal from the sensor element or a signal derived therefrom (e.g., after amplification and digitization), and configured to determine the angular position and / or the linear position in the manner as described above (e.g., according to Figures 4 to 15 The linear position or angular position may be provided at the output of the device, for example in a digital or analog manner.

[0269] The position sensor device 2120 may include a non-volatile memory 2121, which may include computer-executable instructions for obtaining and processing sensor signals. The non-volatile memory 2121 may also include one or more constants, such as the constant "K" used in equation [2], or the constants "M" and "T" used in equation [3], or the constant "L" used in equation [4], but may also include other information.

[0270] Figure 22 A block diagram of a position sensor system 2200 including a first subsystem and a second subsystem is shown.

[0271] The first subsystem includes a first magnetic source 2230 having dual tracks (e.g., Figures 1 to 3 ) and a first position sensor device 2231, and is configured to provide a first position that is highly accurate (e.g., with an error of less than ±0.15°) but has a relatively small measurement range (e.g., a range of 360° / 16=22.5°).

[0272] The "actual mechanical angle" can be calculated as the angle determined as described above and the sum of integer multiples of the angular range. Similarly, the "actual mechanical linear position" can be calculated as the sum of the position X described above and integer multiples of the linear pole pitch. The value of this integer can be determined dynamically (e.g., by counting, starting from a known position), or can be determined by using a second position sensor system that is mechanically coupled (e.g., by directly using a common shaft, or indirectly using a gear mechanism, or in other suitable ways) to the first subsystem. It should be noted that, for example, in the case of a multi-steering system (e.g., a steering wheel), the angular position to be determined can be a value outside the range from 0° to 360°.

[0273] The second subsystem comprises a second magnetic source 2232 in the form of a dipole magnet and a second position sensor device 2233 and is configured to provide a second position which is less accurate but spans a 360° angular range.

[0274] Figure 22 The position sensor system 2200 further includes an external processor (e.g., an electronic control unit, ECU) that is communicatively connected to the first sensor device 2231 and the second sensor device 2233 and is configured to combine the two signals to generate a high-accuracy position sensor signal having a relatively large range (e.g., a range of 360° or greater). Algorithms for combining such signals are known in the art and therefore do not need to be explained in more detail here.

[0275] In an embodiment, the first magnetic source 2230 and the second magnetic source 2232 are mechanically connected via a common shaft 2240. Figure 22 In FIG, the shaft is illustrated as a through shaft for both subsystems, but this is not absolutely necessary, and either the first magnetic source or the second magnetic source may be mounted at one end of the shaft.

[0276] In another embodiment, the first magnetic source 2230 and the second magnetic source 2232 are mechanically connected via a gearbox. Figure 22 In a variation of the system, there is no external processor (ECU), but the first sensor device 2231 is configured to provide its output signal to the second sensor device 2233, and the second sensor device is further configured to combine the two signals.

Claims

1. A position sensor system (100; 200; 300) for determining a position (φ, x) of a sensor device (101; 201; 301), the sensor device (101; 201; 301) being movable relative to a magnetic source (102; 202; 302) along a predefined path, or the magnetic source (102; 202; 302) being movable relative to the sensor device (101; 201; 301) along a predefined path, the position sensor system comprising: The sensor device (101; 201; 301); The magnetic source (102; 202； 302), comprising a first plurality (N1) of alternating magnetic poles arranged along a first track (T1), and comprising a second plurality (N2) of alternating magnetic poles arranged along a second track (T2), wherein the centers of the magnetic poles are spaced apart by a predefined pole pitch (pp); wherein a centerline (C1) of the first track (T1) and a centerline (C2) of the second track (T2) are spaced apart by a predefined track distance (dt), and wherein the magnetization of the first track (T1) and the magnetization of the second track (T2) are substantially 180° phase-shifted; and wherein said second plurality (N2) is equal to said first plurality (N1); wherein the sensor device (101; 201; 301) comprises a substrate having a plurality of magnetic sensors along the predefined path spanning a distance less than 1.40 times the pole pitch (pp); The sensor device is further configured for deriving a plurality of difference signals (diff1, diff2) from a plurality of magnetic field components (BxA, BzA, BxB, BzB), and for deriving the position from the plurality of difference signals (diff1, diff2); It is characterized in that The substrate is oriented parallel to the surface of the magnetic source (102; 202; 302) or tangential to the surface of the magnetic source (102; 202; 302); The plurality of magnetic sensors are configured to measure the plurality of magnetic field components (BxA, BzA, BxB, BzB), the plurality of magnetic field components (BxA, BzA, BxB, BzB) comprising: a first magnetic field component (BxA) oriented parallel to the substrate at a first sensor position (A) above the first track (T1); a second magnetic field component (BxB) parallel to the first magnetic field component at a second sensor position (B) above the second track (T2); a third magnetic field component (BzA; BzC) oriented perpendicular to the substrate at the first sensor position (A) or at a third sensor position (C) above the first track (T1); A fourth magnetic field component (BzB; BzD) is oriented perpendicular to the substrate at the second sensor position (B) or at a fourth sensor position (D) located above the second track (T2).

2. The position sensor system according to claim 1, in, The first magnetic field component (BxA) and the second magnetic field component (BxB) are oriented in directions tangential to a center line (c1) of the first track (T1) and a center line (c2) of the second track (T2).

3. The position sensor system according to claim 1, in, The magnetic sensor is incorporated into the substrate; Or wherein the magnetic sensor is mounted to the substrate.

4. The position sensor system according to claim 1, in, The magnetic source has a planar surface, and the sensor device is mounted above the planar track at a distance in the range of 0.5 mm to 5.0 mm; Or wherein the magnetic source has a cylindrical surface and the sensor device is mounted at a distance in the range of 0.5 mm to 5.0 mm above the cylindrical track.

5. The position sensor system according to claim 1, in, The sensor device comprises two 2D magnetic sensors, each 2D magnetic sensor comprising an integrated magnetic flux concentrator (IMC1, IMC2) and two horizontal Hall elements (FIG. 19: H1 to H4); or The sensor device includes two 2D magnetic sensors, and each 2D magnetic sensor includes a horizontal Hall element and a vertical Hall element ( FIG. 20 : H1 , V1 , H2 , V2 ).

6. The position sensor system (300) according to claim 1, in, Each of the predefined path, the first trajectory (T1) and the second trajectory (T2) is linear.

7. The position sensor system (100; 200) according to claim 1, in, The first track (T1) and the second track (T2) have a circular or annular shape with a common center, and wherein the sensor device (101; 201) is located at a non-zero distance from the center.

8. The position sensor system according to claim 1, in, The plurality of difference signals include a first difference signal (diff1) and a second difference signal (diff2), the first difference signal (diff1) being determined between the first magnetic field component (BxA) and the second magnetic field component (BxB), and the second difference signal (diff2) being determined between the third magnetic field component (BzA; BzC) and the fourth magnetic field component (BzB; BzD); And wherein the position is determined as a function of a ratio of the first difference signal (diff1) to the second difference signal (diff2).

9. The position sensor system according to claim 8, in, The position is determined according to one of the following formulas: φ = arctan(R), or φ = arctan(K*R), or φ=arctan(R / M±T), wherein diff1 is the first difference signal, diff2 is the second difference signal, R is the ratio of the first difference signal to the second difference signal, and K and M are predefined constants different from 1.0, for example, K and M are greater than 1.05 or less than 0.95; and wherein T is a predefined constant different from 0, for example, T has an absolute value of at least 0.

05.

10. The position sensor system according to claim 1, in, The first track (T1) has a first width (w1) in the range from 1.0 to 3.0 mm, or in the range from 1.5 to 2.5 mm; and wherein the second track (T2) has a second width (w2) in the range from 1.0 to 3.0 mm, or in the range from 1.5 to 2.5 mm; And wherein the distance between the first sensor position (A) and the second sensor position (B) is a value in the range from 1.0 mm to 3.0 mm, or in the range from 1.5 mm to 2.5 mm.

11. The position sensor system (2200) according to claim 1, in, The magnetic source (102; 202) is mounted to a shaft (2240), and wherein the sensor device (101; 201) is configured to determine a first angular position of the shaft; and wherein the position sensor system (2200) further comprises a two-pole magnet (2232) mechanically coupled directly or indirectly to the shaft, and further comprises a second sensor device (2233) configured to determine a second angular position of the shaft; And wherein the position sensor system (2200) is further configured to combine the first angular position and the second angular position.

12. The position sensor system according to claim 1, in, a distance (ds) between the first sensor position (A) and the second sensor position (B) being less than a sum of a first width (w1) of the first track (T1) and a second width (w2) of the second track (T2), or less than 80% of the sum, or less than 70% of the sum, or less than 60% of the sum, or less than 50% of the sum, or less than 40% of the sum; Or wherein the distance (ds) between the first sensor position (A) and the second sensor position (B) is less than 2.00 times the track distance (dt), or less than 1.50 times the track distance (dt), or less than 1.25 times the track distance (dt), or less than 1.00 times the track distance (dt), or less than 0.90 times the track distance (dt).

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