Magnetic field-based angle sensor system with stray field compensation and corresponding method

Abstract

Embodiments of the present disclosure relate to a magnetic field-based angle sensor system with stray field compensation and corresponding methods. The innovative solution described herein relates to a magnetic field-based angle sensor system (100) having a stator component (104) and a rotor component (102) rotatable relative to the stator component, a magnetic field sensor (110) operating in saturation mode and a magnetic field sensor (120) operating in linear mode. The magnetic field sensor operating in saturation mode is designed to determine the rotational angle of the rotor component relative to the stator component, and the magnetic field sensor operating in linear mode is designed to determine the external stray magnetic field acting on the angle sensor system. The angle sensor system further has a control device (130) which is designed to compensate for measurement deviations related to the stray field during the determination of the rotational angle based on the determined external stray magnetic field.

Description

Technical Field

[0001] The innovative solutions described herein relate to magnetic field-based angle sensor systems, and in particular to magnetic field-based angle sensor systems with integrated stray field compensation for reducing and / or compensating measurement deviations when determining the rotational angle between a rotor and a stator. Background Art

[0002] Angle sensors are used to determine the rotational angle between a stator and a rotor that can rotate relative to the stator. Here, it can involve rotations of a few degrees, or rotations of 360° and more. For example, the rotor can rotate around its own axis or relative to the stator multiple times and partly at very high angular velocities.

[0003] Such angle measurement systems of the described type produce a sine component also referred to as the y-component and a cosine component also referred to as the x-component. The arctangent function (also referred to as arctan, ata or tan -1 ) can then be used to determine the rotational angle according to the following formula:

[0004]

[0005] Such magnetic field-based angle sensors are used, for example, in the automotive field, for example in the electrical commutation of electric motors. The requirements for angle accuracy, that is, the accuracy of angle measurement, are continuously increasing here. An angle deviation of <0.2° is sometimes required when measuring the rotational angle. However, the implementation of such a small tolerance range is extremely difficult in practice because especially external stray magnetic fields can cause undesired measurement deviations that negatively affect the required accuracy.

[0006] To mitigate or compensate for the negative effects of these external stray magnetic fields, magnetic shielding can be used. However, the provision and assembly of such magnetic shielding lead to an increase in the working costs and cost of the application in terms of construction and manufacturing. Summary of the Invention

[0007] To meet the demand for high precision in angle determination, a magnetic field-based angle measurement system according to the present invention with integrated stray field compensation is proposed in the present disclosure, and a corresponding method for stray field compensation according to the present invention is also proposed. Embodiments of the angle sensor and the corresponding method for stray field compensation and other advantageous aspects are mentioned below.

[0008] The innovative magnetic field-based angle sensor system described herein includes a stator component and a rotor component rotatable relative to the stator component, wherein the rotor component has a multi-pole magnet. In addition, the angle sensor system has a magnetic field sensor operating in saturation operation and a magnetic field sensor operating in linear operation, wherein the magnetic field sensor operating in saturation operation is designed to determine the rotational angle of the rotor component relative to the stator component based on the magnetic field of the multi-pole magnet. The magnetic field sensor operating in linear operation is designed to determine the external stray magnetic field acting on the angle sensor system. The angle sensor system also has a control device, which is designed to reduce and / or compensate for measurement deviations related to the stray field in the determination of the rotational angle performed by the magnetic field sensor operating in saturation operation based on the external stray magnetic field determined by the magnetic field sensor operating in linear operation.

[0009] In addition, a corresponding method for reducing and / or compensating measurement deviations when determining the rotational angle by means of a magnetic field-based angle sensor system is proposed, wherein the method has the steps of: providing a stator component and a rotor component rotatable relative to the stator component, wherein the rotor component has a multi-pole magnet. In addition, the method includes providing a magnetic field sensor operating in saturation operation and a magnetic field sensor operating in linear operation. The rotational angle between the rotor component and the stator component can be determined by means of the magnetic field sensor operating in saturation operation, more precisely, this determination is based on the magnetic field of the multi-pole magnet. The external stray magnetic field acting on the angle sensor system can be determined by means of the magnetic field sensor operating in linear operation. Based on the determined stray magnetic field, measurement deviations related to the stray field can then be reduced and / or compensated for when determining the rotational angle. Description of the Drawings

[0010] Some embodiments are illustrated by way of example in the drawings and are described below. Shown are:

[0011] Figure 1 A schematic side view of an angle sensor system in a so-called end-of-shaft (EoF) implementation according to an embodiment is shown,

[0012] Figure 2 A schematic top view of an angle sensor system according to an embodiment is shown,

[0013] Figure 3 A schematic block diagram for describing the scheme for stray field compensation described herein according to an embodiment is shown,

[0014] Figures 4A to 4C A schematic diagram for visualizing the effect of the stray magnetic field on the operating magnetic fields of the sensors operating in saturation operation and in linear operation is shown,

[0015] Figure 5A A schematic block diagram showing a solution for stray field compensation using pre-CORDIC as described herein according to an embodiment.

[0016] Figure 5B A schematic block diagram showing a solution for stray field compensation using post-CORDIC as described herein according to an embodiment.

[0017] Figure 6A 、 6B A function showing an analog angular measurement signal for a solution for stray field compensation as described herein according to an embodiment.

[0018] Figure 7 A schematic block diagram showing a method for stray field compensation as described herein according to an embodiment.

[0019] Figure 8 A graph showing output signals of an actual and an ideal vertical Hall effect sensor for making a decision on the correct half-plane when determining an electrical angle using an AMR-based sensor as described herein according to an embodiment.

[0020] Figure 9 A magnitude circle showing the correction of the half-plane in an AMR-based sensor as described herein according to an embodiment.

[0021] Figure 10 Another magnitude circle showing the correction of the half-plane in an AMR-based sensor according to another embodiment as described herein.

[0022] Figure 11 A simulation result showing a sensor output signal with correction of the half-plane in an AMR-based sensor as described herein according to an embodiment, and

[0023] Figure 12 A simulation result showing the residual angular error in an AMR-based sensor after half-plane correction as described herein according to an embodiment. DETAILED DESCRIPTION

[0024] Embodiments are described in more detail below with reference to the accompanying drawings, in which elements having the same or similar functions are provided with the same reference numerals.

[0025] The method steps illustrated in block diagrams and explained with reference to the block diagrams can also be executed in an order different from that shown and described. In addition, method steps related to a specific feature of a device can be interchanged with that same feature of the device, and vice versa.

[0026] Whenever compensation is mentioned within the scope of this disclosure, especially stray field compensation, it is to be understood here as attenuation or reduction. Thus, stray field compensation is the attenuation or reduction of measurement deviations caused by stray fields. However, the term compensation can also be understood here as the complete reduction or elimination of measurement deviations.

[0027] If a multipole magnet is mentioned within the scope of this disclosure, this refers to a magnet having at least two different poles, and especially a permanent magnet. Here, a multipole magnet can be, for example, a dipole magnet having a north pole and a south pole, a quadrupole magnet having two north poles and two south poles, a hexapole magnet having three north poles and three south poles, etc. The poles of the multipole magnet can be, for example, radially opposed. The multipole magnet can have different geometries. For example, the multipole magnet can have an annular shape. In addition, everything described here by way of example for a dipole magnet also applies to multipole magnets. And vice versa.

[0028] Figure 1 Shown is a magnetic field-based angle sensor system 100 according to an example arrangement. This is a so-called end-of-shaft (EoS) arrangement, in which a multipole magnet 101 is arranged at the end of a rotatable shaft 102. In this non-limiting example, the multipole magnet 101 can be a bipolar magnet (dipole magnet). In this case, the rotatable shaft 102 is a rotor component that rotates about a rotation axis 105.

[0029] A housing 103 is arranged opposite the multipole magnet 101. The housing 103 can be arranged on a stator component 104 (for example, a printed circuit board (PCB)). The housing 103 can have an angle sensor system. The angle sensor system can have at least one magnetic field sensor. The magnetic field sensor can be a magnetic angle sensor, which is designed to determine the current rotation angle of the multipole magnet 101 rotating with the shaft 102 (rotor component) relative to the stator component 104.

[0030] The magnetic field sensor can be, for example, a magnetoresistive magnetic field sensor, and especially a magnetic field sensor operating in saturation mode. As a non-limiting example, the magnetic field sensor can include an AMR sensor utilizing the anisotropic magnetoresistive effect (AMR), a GMR sensor utilizing the giant magnetoresistive effect (GMR), a CMR sensor utilizing the colossal magnetoresistive effect (CMR), or a TMR sensor utilizing the magnetic tunnel resistance effect (TMR), the so-called TMR sensor. Within the scope of this disclosure, such magnetoresistive magnetic field sensors operating in saturation mode are also subsumed under the abbreviation xMR sensors.

[0031] Such a magnetic field sensor operating in saturation mode generates a sine component also referred to as the y-component and a cosine component also referred to as the x-component. Then, the arctangent function (also referred to as arctan, Atan, or tan -1) is used to calculate the rotation angle between the rotor and stator parts according to the following formula:

[0032]

[0033] xMR sensors have a very good signal-to-noise ratio (SNR). AMR sensors also have excellent stability against phase drift and with respect to higher harmonic errors. However, AMR sensors are limited to an angular range of 180°, i.e., AMR sensors only provide clear results about the rotation angle to be measured in a range of 180°. In addition, AMR sensors may sometimes have drifts and recognizable offsets in their output signal amplitude.

[0034] Alternatively or additionally, in Figure 1 The angle sensor system depicted in can have a magnetic field sensor operating in linear operation. For this purpose, Hall sensors or also xMR sensors operating in linear operation are mentioned as non-limiting examples. Hall sensors have excellent linearity. In addition, the Hall sensors can have an offset compensation (e.g. current rotation), which reduces and / or compensates for inherent, that is to say system-inherent, offsets.

[0035] Both types of magnetic field sensors are susceptible to external interference fields, so-called external stray magnetic fields. These stray fields lead to deviations or errors in the angle measurement. The Earth's magnetic field alone can already lead to significant deviations when determining the rotation angle between the rotor part and the stator part. Thus, for example, in a magnetic field sensor with an operating magnetic field amplitude of 20 mT, stray fields of approximately 100 μT (which roughly corresponds to the Earth's magnetic field) can already lead to angular errors of 0.3° and more.

[0036] Therefore, in order to improve this problem in the existing angle sensor system, it is proposed to provide an angle sensor system with integrated stray field compensation. A section of this innovative angle sensor system is Figure 2 It is shown as an example in FIG.

[0037] Figure 2 A schematic top view of a magnetic field based angle sensor system 100 according to the innovative solution described herein is shown. Figure 1 As depicted, the angle sensor system 100 may be arranged in a package 103. The package 103 or the angle sensor system 100 may be arranged on a substrate 104 such as a PCB. The substrate 104 may be a part of a stator component.

[0038] The angle sensor system 100 may include at least one magnetic field sensor 110 operating in a saturation operating mode. The magnetic field sensor 110 operating in saturation may optionally have one or more sensor bridges, which are shown in dashed lines herein and are provided with reference numerals 111, 112, ..., 118.

[0039] The angle sensor system 100 may also have at least one magnetic field sensor 120 operating in a linear operating mode. However, the angle sensor system 100 may also optionally have a plurality of magnetic field sensors operating in a linear operating mode, wherein another such magnetic field sensor is shown in dashed lines herein and is provided with reference numeral 121. Only the at least one magnetic field sensor 120 operating in a linear operating mode will be described in more detail below, where, of course, all embodiments equally apply to all other magnetic field sensors 121, etc. operating in a linear operating mode.

[0040] The magnetic field sensor 110 operating in saturation may be an xMR sensor. The xMR-based angle sensor 110 typically operates in saturation. This angle sensor measures the angle (cosine and sine) of the resultant magnetic field. This measurement method is particularly well-suited for determining the rotational angle with high resolution.

[0041] Although xMR-based sensors may have devices for intrinsic offset compensation, i.e., for compensating offsets caused, for example, by the sensor element itself or the electronic signal path, xMR-based sensors are susceptible to interfering magnetic fields (e.g., external stray magnetic fields). Due to saturation operation, the quantization of the magnetic offset caused by external stray magnetic fields cannot be achieved indefinitely in xMR-based sensors, and this magnetic offset directly results in a finite angle error. In addition, xMR-based sensors generally lack the possibility for magnetic offset compensation, i.e., for compensating offsets caused by external stray magnetic fields. However, these magnetic offsets limit the achievable measurement accuracy for standard end-of-shaft (EoS) applications.

[0042] In the linear angle sensors used here, or in magnetic field sensors operating in a linear operating mode, generally this magnetic offset propagates linearly. Therefore, the magnetic offset can be particularly well quantified by means of a magnetic field sensor operating in a linear operating mode. This applies in particular when the magnetic field sensor operating in a linear operating mode also has an inherent offset compensation (e.g., by means of current rotation). A non-limiting example of such a magnetic field sensor operating in a linear operating mode is a Hall sensor or a Hall element. Therefore, the magnetic field sensor operating in a linear operating mode has a minimum residual offset. In addition, the stray magnetic field can be determined and compensated very precisely. However, the magnetic field sensor operating in a linear operating mode has a low SNR, and in addition is sensitive to changes in mechanical stress, especially shear stress.

[0043] Now, the innovative solution proposed here provides an angle sensor system 100 based on a magnetic field ( Figure 2 ), wherein the angle sensor system 100 has at least one magnetic field sensor 110 operating in saturation mode and additionally has at least one magnetic field sensor 120 operating in linear mode.

[0044] The magnetic field sensor 110 operating in saturation mode can be designed to determine the rotational angle of the rotor component 102 relative to the stator component 104 based on the magnetic field of the multipole magnet 101 ( Figure 1 ). The magnetic field sensor 120 operating in linear mode can be designed to determine the external stray magnetic field acting on the angle sensor system 100.

[0045] The angle sensor system 100 can also have a control device 130, which is designed to reduce and / or compensate for measurement deviations related to the stray field when determining the rotational angle based on the external stray magnetic field that can be determined by the magnetic field sensor 120 operating in linear mode, wherein the determination of the rotational angle can in turn be performed by the magnetic field sensor 110 operating in saturation mode.

[0046] That is, information about the stray magnetic field determined by the magnetic field sensor 120 operating in linear mode can be used to reduce or compensate for measurement errors or measurement deviations of the magnetic field sensor 110 operating in saturation mode.

[0047] Figure 3 A schematic block diagram is shown for illustrating conceivable designs for reducing or compensating for external stray magnetic fields. Whenever a stray magnetic field is mentioned here, it can be understood that the stray magnetic field relates to a quasi-static stray magnetic field, that is, a stray field that changes significantly more slowly than the rotational frequency of the magnetic field used for angle measurement. Such a stray magnetic field can cause a constant offset that is added to the magnetic field used for angle measurement.

[0048] The magnetic field sensor 120 operating in linear mode can generate an output signal 310, which can have a correlation with such an external stray magnetic field. For example, the output signal 310 can additionally have a correlation with the intensity of such an external stray magnetic field, which means that the stronger the stray field, the greater the effect on the output signal 310. Now, automatic calibration 320 can be applied to the output signal 310 again. The automatic calibration 320 can be, for example, a calibration in which the amplitude shift and / or phase shift and / or offset of the output signal 310 caused by the stray field are determined.

[0049] Therefore, stray field information 330 can be determined in the automatic calibration 320. The stray field information can be said to describe the stray fields. These stray field information can then be applied to the output signal 340 of the magnetic field sensor 110 operating in saturation operation in order to reduce and / or compensate for measurement deviations.

[0050] That is, the magnetic field sensor 110 operating in saturation operation generates an output signal 340, which can be used for angle measurement between the rotor component 102 and the stator component 104. The output signal 340 representing the rotational angle of the magnetic field sensor 110 operating in saturation operation has a correlation with the external stray magnetic field. The stray field information 330 determined during the automatic calibration 320 of the magnetic field sensor 120 operating in linear operation, or rather, can then be used to reduce or compensate for the correlation between the output signal 340 of the magnetic field sensor 110 operating in saturation operation and the external stray magnetic field. That is, the stray field information 330 can include parameters related to the stray fields, and these parameters can be used to compensate or reduce the measurement error of the magnetic field sensor 110 operating in saturation operation. For this reason, the stray field information 330 can also be referred to as compensation parameters related to the stray fields.

[0051] As already mentioned at the beginning, the external stray magnetic field can add a certain constant offset to the output signal 340 of the magnetic field sensor 110 operating in saturation operation. In order to reduce or compensate for this offset, the compensation parameters 330 related to the stray fields can include offset information, which is determined, for example, during the automatic calibration 320 from the output signal 310 of the magnetic field sensor 120 operating in linear operation. Alternatively or additionally, the compensation parameters 330 related to the stray fields can include amplitude information (such as amplitude deviation) determined, for example, during the automatic calibration 320 from the output signal 310 of the magnetic field sensor 120 operating in linear operation.

[0052] This will be explained in more detail below with reference to Figures 4A to 4C These figures schematically show the previously discussed effects of the quasi-static stray magnetic field on the output signals 310, 340 of the magnetic field-based angle sensor system 100 in the EOS application, which angle sensor system has a magnetic field sensor 110 operating in saturation operation and a magnetic field sensor 120 operating in linear operation, as Figure 1 shown.

[0053] Figure 4A Shows the magnetic field vector B generated by the multipole magnet 101 under the influence of the quasi-static stray magnetic field B stray and the resulting effective magnetic field B mag along with the associated angle information containing deviated angle information eff ​ As shown by the circle 401 indicated by the solid line, the effective magnetic field describes a circle offset by an offset with respect to the origin as a function of the angle.

[0054] Figure 4B Shows an ideal magnetic field sensor 110 (here: GMR sensor) operating in saturation with a signal amplitude S GMR The systematic response to the effective magnetic field. The magnetic field sensor 110 operating in saturation normalizes the magnitude of the magnetic field vector to its own signal amplitude S GMR . For this reason, the output of the magnetic field sensor 110 as a function of the angle describes a circle whose center is at the origin. However, every information about the external stray magnetic field is lost here. However, the output signal Contains an angular error (measurement deviation) due to the stray magnetic field.

[0055] Figure 4C Shows an ideal magnetic field sensor 120 (here: Hall effect sensor) operating in linearity with a signal sensitivity S VHall The systematic response to the effective magnetic field. The magnetic field sensor 120 operating in linearity can be said to calibrate the effective magnetic field vector based on its sensitivity S VHall . For this reason, the output of the magnetic field sensor 120 as a function of the angle describes a circle whose center is offset with respect to the origin by the stray magnetic field. As previously referred to Figure 3 As already explained, the stray field information 330 can be obtained, for example, by means of an automatic calibration 320, and its unwanted effect on the sensor output signal 340 of the magnetic field sensor 110 operating in saturation can be reduced or compensated, in order to thereby obtain the original angular information

[0056] The following presents possible embodiments for reducing or compensating the measurement deviation caused by the stray field during angle determination by means of a mathematical proof:

[0057] Generally, in EOS applications, the effective magnetic field under the influence of an external stray magnetic field B stray =(Bsx, Bsy) T Is given by the formula:

[0058]

[0059] An ideal magnetic field sensor operating in linearity responds to such an effective magnetic field by simply calibrating the effective magnetic field according to the following formula using its sensitivity:

[0060]

[0061] For example, as previously referenced Figure 3 the automatic calibration (e.g., min / max search) as described results in compensation parameters 330 related to the stray field. The compensation parameters 330 related to the stray field can, for example, include offset information (Ox, Oy) and / or amplitude information (Ax, Ay) of the output signal of the magnetic field sensor 120 operating in linear operation:

[0062]

[0063] Here, Ax = (max(X VHall )) - min(X VHall )) / 2 describes the amplitude, and Ox = (max(X VHall )) + min(X VHall )) / 2 describes the offset of the x-channel. Ay and Oy represent the amplitude and offset of the y-channel. For the purpose of performing automatic calibration, it is advantageous to sweep at least one interval of at least 360° between the rotor component and the stator component. The quasi-static stray magnetic field B stray (normalized by the amplitude of the magnetic field B0) can be quantified from these compensation parameters according to the following formula:

[0064]

[0065] The compensation parameters 330 related to the stray field can thus, for example, have a ratio between the offset information Ox, Oy and the amplitude information Ax, Ay according to the following formula:

[0066] Offset information (x) / Amplitude information (x) = Ox / Ax, and

[0067] Offset information (y) / Amplitude information (y) = Oy / Ay.

[0068] As shown below, this stray field information or the offset information (Ox, Oy) and / or amplitude information (Ax, Ay) contained in this stray field information is already sufficient to determine the effect of the quasi-static stray magnetic field and apply the corresponding stray field compensation to the output signal 340 of the magnetic field sensor 110 operating in saturation operation.

[0069] An ideal magnetic field sensor operating in saturation operation responds to the effective magnetic field according to the following formula (1) due to the cosine component and sine component of the effective angle generated by the magnetic field sensor:

[0070]

[0071] In formula (5), the factor N xMRis introduced to distinguish between different xMR technologies. For GMR and TMR technologies that provide a well-defined output signal over the entire 360° cycle, N xMR = 1, while for AMR technology that provides a well-defined output signal only within an interval of 180°, N xMR = 2.

[0072] For GMR and TMR (N xMR = 1), a first-order Taylor series expansion from Equation (5) to (B stray / B0) is obtained:

[0073]

[0074] Here, a correction factor is introduced. In the following text, higher-order terms are represented by σ(stray 2 ). By inverting Equation (6) and neglecting higher-order terms, the following is obtained:

[0075]

[0076] Here, C2(X2, Y2) = (1 + Ox / Ax·X2 + Oy / Ay·Y2) represents the inverted correction factor (up to the first order), and X2 and Y2 represent the AOP-compensated xMR output signal (for the term AOP compensation, see below).

[0077] Similarly, the influence of the external stray magnetic field on the output signal 340 representing the rotation angle of the magnetic field sensor 110 operating in saturation can be determined. For this purpose, the arctangent function (or arctan2) can be applied to Equation (5). A subsequent first-order Taylor series expansion up to (B stray / B0) is obtained:

[0078]

[0079] Different from Equation (6) which cannot be unrestrictedly applied to AMR sensors, Equation (8) is applicable to angle sensors based on GMR, TMR, and AMR. If Equation (8) is now inverted and higher-order terms are again neglected, the following is obtained:

[0080]

[0081] Here, X2 and Y2 represent the AOP-compensated xMR output signal (for AOP compensation, see below). For AMR-based angle sensors, it is advantageous to determine the angle The correct half-plane. This can be done, for example, by measuring "quadrant information" from the signal path of a magnetic field sensor 120 (such as a Hall effect sensor) operating in linear operation or by internally tracking the corresponding quadrants.

[0082] As already mentioned at the beginning, a magnetic field sensor 110 operating in saturation operation can determine the rotational angle between the rotor component 102 and the stator component 104 by calculating the arctangent function of the sine and cosine components of the output signal according to the following formula:

[0083]

[0084] The calculation of the rotational angle is also referred to as CORDIC here. For TMR- and GMR-based angle sensors, their output signals compensated for AOP and can be directly used for the calculation of the rotational angle (CORDIC). For AMR-based angle sensors, an additional CORDIC implementation is required beforehand to calculate the sine and cosine of the angle of.

[0085] Formulas (3), (4), (7), and (9) form the basis for the automatic calibration and stray field compensation described here. Here, the stray field compensation itself can be carried out in different ways. For example, the output signal 340 of the magnetic field sensor 110 operating in saturation operation can be compensated (so-called pre-CORDIC) in the case of using the stray field-related compensation parameter 330 (obtained by means of the magnetic field sensor 120 operating in linear operation), more precisely before calculating the rotational angle. Alternatively, the rotational angle can first be calculated from the output signal 340 of the magnetic field sensor 110 operating in saturation operation, and then the stray field-related compensation parameter 330 (obtained by means of the magnetic field sensor 120 operating in linear operation) can be applied to the calculated rotational angle for the purpose of stray field compensation (so-called post-CORDIC).

[0086] Figure 5A A schematic block diagram is shown for representing an embodiment for stray field compensation, in which first the output signal 340 of the magnetic field sensor 110 operating in saturation operation is compensated in the case of using the stray field-related compensation parameter 330 (obtained by means of the magnetic field sensor 120 operating in linear operation), and then the rotational angle is calculated (pre-CORDIC).

[0087] In Figure 5ASchematically shown is a magnetic field sensor 110 operating in saturation operation and a magnetic field sensor 120 operating in linear operation. The signal path of the magnetic field sensor 110 operating in saturation operation is divided into a first signal path 110A including the cosine component of the sensor signal and a second signal path 110B including the sine component of the sensor signal. This also applies to the magnetic field sensor 120 operating in linear operation. The signal path of the magnetic field sensor 120 operating in linear operation is divided into a first signal path 120A including the cosine component of the sensor signal and a second signal path 120B including the sine component of the sensor signal.

[0088] The output signal 340 of the magnetic field sensor 110 operating in saturation operation can optionally undergo a so-called AOP correction 360. The term AOP stands for amplitude-phase-offset. That is, as long as the amplitude shift and / or phase shift and / or static offset are reduced or compensated, the output signal 340 can be processed. The AOP correction 360 can include an AOP calibration 361 and subsequent AOP compensation 362, where the AOP calibration 361 provides corresponding AOP parameters 363, and the AOP parameters can then be applied to the output signal 340 for AOP compensation.

[0089] According to such an embodiment, the control device 130 can thus be designed to perform an amplitude-phase-offset-correction 360 of the output signal 340 of the magnetic field sensor 110 operating in saturation operation before applying the compensation parameter 330 related to the stray field, where in the amplitude-phase-offset-correction 360, amplitude shift compensation and / or phase shift compensation and / or offset compensation are applied to the output signal 340 of the magnetic field sensor 110 operating in saturation operation.

[0090] This AOP correction 360 minimizes linear irregularities in the xMR signal path, such as offsets and amplitude shifts. For the purpose of the AOP correction 360, for example, minimum / maximum determination can be applied to the output signal 340 (X xMR and Y xMR ), especially in an interval of at least 360° for GMR- and TMR-based sensors, or alternatively in an interval of 180° for AMR-based sensors. From the found maximum and minimum values, the amplitudes Ax xMR , Ay xMR and the offsets Ox xMR , Oy xMR in the corresponding signal paths 110A, 110B can then be determined.

[0091] When the AOP automatic calibration 361 is completed, i.e., once a sufficiently good estimate of the AOP parameters 363 has been achieved, these AOP parameters 363 can be used for AOP compensation 362 such that the output signals X2, Y2 of the AOP compensation are obtained according to the following formula:

[0092] X2 = (X xMR - OX xMR ) / Ax xMR and Y2 = (Y xMR - Oy xMR ) / Ay xMR .

[0093] The AOP automatic calibration 361 can be carried out continuously to improve the results over time when determining the AOP parameters 363 from which it can be derived.

[0094] In parallel with this, the automatic calibration 320 of the output signal 310 of the magnetic field sensor 110 operating in linear operation, which has been described previously with reference to Figure 3 , can be performed. Thereby, the compensation parameters 330 related to the stray field can be obtained. The compensation parameters 330 related to the stray field can be obtained, for example, according to the above formula (4). In particular, the compensation parameters 330 related to the stray field can include the amplitude information and / or offset information of the output signal 310, such as the relationships Ox / Ax and Oy / Ay listed previously in formula (4).

[0095] The compensation parameters 330 related to the stray field can then be used for stray field compensation of the (optionally AOP-compensated) output signal 340 or X2, Y2 of the magnetic field sensor 110 operating in saturation operation. For example, in the case of applying the above formula (7), the stray field compensation results in the stray field-compensated output signals X4, Y4, which can then be considered for calculating the stray field-compensated rotation angle (see the angle calculation CORDIC in block 370).

[0096] Optionally, the output signal 310 of the magnetic field sensor 120 operating in linear operation can be subjected to additional compensation 380, whereby the quadrant information can be derived specifically for AMR-based sensors. These quadrant information can then be considered when calculating the stray field-compensated rotation angle .

[0097] Overall, therefore, in Figure 5AIn the previously described CORDIC scheme shown, the control device 130 can be designed to perform an angle calculation indicating the rotational angle of the rotor component 102 relative to the stator component 104 based on the output signal 340 of the magnetic field sensor 110 operating in saturation operation, and the control device 130 can also be designed to apply a compensation parameter 330 related to the stray field to the output signal 340 of the magnetic field sensor 110 operating in saturation operation before the angle calculation, so as to compensate for the measurement deviation when determining the rotational angle accordingly.

[0098] Figure 5B Shows an alternative for determining the rotation angle compensated for stray fields Here, the aforementioned post-CORDIC scheme is involved, in which, first, the effective rotation angle is calculated from the (optionally AOP-compensated) output signal 340 or X2, Y2 of the magnetic field sensor 110 operating in saturation operation And subsequently, for the purpose of stray field compensation, the compensation parameter 330 related to the stray field (obtained by means of the magnetic field sensor 120 operating in linear operation) is applied to the calculated rotation angle (so-called post-CORDIC), so as to obtain the rotation angle compensated for stray fields accordingly

[0099] Having the same functional blocks with the same functions as in Figure 5A are provided with the same reference numerals, so the repeated description is omitted here, and instead reference is made to Figure 5A the implementation.

[0100] Compared with Figure 5A the difference is especially that here, in block 370, the effective magnetic angle is first calculated (CORDIC) based on the (optionally AOP-compensated) output signal 340 or X2, Y2 of the magnetic field sensor 110 operating in saturation operation. The angle calculation (CORDIC) can be performed, for example, according to the first line of formula (9), where, for AMR-based sensors, the correct half-plane should be considered. Subsequently, in block 390, for the purpose of stray field compensation, the compensation parameter 330 related to the stray field can be applied to the previously calculated effective magnetic angle as shown, for example, in the second line of formula (9). As a result, the rotation angle compensated for stray fields is obtained accordingly

[0101] Overall, therefore, in Figure 5BIn the post-CORDIC solution shown, the control device 130 can be designed to perform an angle calculation indicating the rotational angle of the rotor component 102 relative to the stator component 104 based on the output signal 340 of the magnetic field sensor 110 operating in saturation operation, and the control device 130 can also be designed to apply a compensation parameter 330 related to the stray field to the result of the angle calculation after the angle calculation, so as to compensate for the measurement deviation when determining the rotational angle thereby.

[0102] To confirm the innovative method described herein, two simulations have been performed, with reference to Figure 6A and Figure 6B to describe these two simulations in more detail. Figure 6A Shows the measurement results, where the Hall effect sensor 120 operating in linear operation is combined with the GMR-based sensor 110 operating in saturation operation. Figure 6B Shows the measurement results, where the Hall effect sensor 120 operating in linear operation is combined with the AMR-based sensor 110 operating in saturation operation.

[0103] In both measurements, a working magnetic field with an amplitude of B0 = 20 mT is assumed. In addition, it is also assumed that the stray magnetic field B stray =(100 μT, 30 μT) T . Both the pre-CORDIC and post-CORDIC stray field compensations are applied to compensate or reduce the measurement error in the determination of the rotational angle according to the principles described herein. As can be seen in the drawings, the innovative solution described herein reduces the effect of the stray magnetic field on the calculation of the rotational angle by two orders of magnitude.

[0104] Therefore, in Figure 6A (Hall effect sensor + GMR sensor) and Figure 6B (Hall effect sensor + AMR sensor), a measurement error 610 in determining the rotational angle is seen, and the rotational angle fluctuates in the range between +0.3° and -0.3° over the full angle range of 360°. That is, due to the external stray magnetic field, a systematic error or deviation of up to 0.6° in the angle measurement is effectively obtained. By using the innovative solution described herein, this measurement error can be reduced or completely compensated, which is shown by the plotted function 620.

[0105] The innovative solution described herein also relates to a corresponding method for stray field compensation in the angle sensor system 100. Therefore, Figure 7 shows an exemplary embodiment of such a method for reducing and / or compensating measurement deviation when determining the rotational angle by means of the magnetic field-based angle sensor system 100.

[0106] In block 701, a stator component 104 and a rotor component 102 rotatable relative to the stator component are provided, wherein the rotor component 102 includes a multi-pole magnet 101.

[0107] In block 702, a magnetic field sensor 110 operating in saturation operation and a magnetic field sensor 120 operating in linear operation are provided.

[0108] In block 703, the rotational angle between the rotor component 102 and the stator component 104 is determined, more precisely, this determination is carried out by means of the magnetic field sensor 110 operating in saturation operation based on the magnetic field of the multi-pole magnet 101.

[0109] In block 704, the external stray magnetic field acting on the angle sensor system 100 is determined by means of the magnetic field sensor 120 operating in linear operation, and the measurement deviation associated with the stray field is compensated when determining the rotational angle, and more precisely, this compensation is carried out based on the determined stray magnetic field.

[0110] Overall, it can thus be determined that according to the innovative concept described herein, a magnetic-field-based angle measurement system or angle sensor system 100 with integrated stray field compensation is proposed. For the purpose of stray field compensation, the angle sensor system 100 includes a combination of a magnetic field sensor 110 operating in saturation operation and a magnetic field sensor 120 operating in linear operation. Thus, the linear characteristic of the signal path of the magnetic field sensor 120 (e.g., Hall effect sensor) operating in linear operation can be combined with the saturation behavior of the signal path of the magnetic field sensor 110 (e.g., xMR sensor) operating in saturation operation. This provides an effective and at the same time cost-effective technical solution for reducing or compensating the measurement deviation caused by an external stray magnetic field, and for this purpose, no expensive additional shielding is required.

[0111] With the innovative concept described herein, the influence of a quasi-static external stray magnetic field on the sensor circuit of the angle sensor system 100 can be compensated in an advantageous manner and method by combining a sensor 110 (e.g., xMR) operating in saturation operation with a sensor 120 (e.g., based on a vertical Hall plate) operating in linear operation. The sensor 110 operating in saturation operation measures the effective rotational angle, which may be affected by measurement errors due to the stray magnetic field. The sensor 120 operating in linear operation determines the magnetic offset established due to the stray magnetic field. This information can then be used to compensate the output signal of the magnetic field sensor 120 operating in saturation operation.

[0112] The combination of the sensor 110 operating in saturation mode and the sensor 120 operating in linear mode is a promising candidate for achieving high-precision angle measurement. In addition, this combination of sensors 110, 120 provides redundant and diverse measurement techniques for functional safety applications. By combining the sensors 110, 120, it can be said that the advantages of the two sensor technologies are combined:

[0113] · Quasi-static stray magnetic fields are compensated;

[0114] · Good signal-to-noise ratio;

[0115] · Excellent phase stability of the AMR-based sensor.

[0116] In other words, the solution described herein describes the automatic calibration and compensation of quasi-static stray magnetic fields for the combined linear and saturation angle sensors 110, 120.

[0117] It has been mentioned several times that AMR-based sensors (as a non-limiting example of the sensor 110 operating in saturation mode) provide unambiguous results only within an angular range of 180°. After the rotor rotates 180° relative to the stator, the angle signal repeats. Therefore, ambiguity may occur when interpreting the measurement results. In order to meaningfully apply the innovative solution proposed herein to AMR-based angle sensors, a solution thereto is proposed below.

[0118] It should be noted again that in the magnetoresistive measurement principle, the signal amplitude is generally not related to the field magnitude compared to Hall effect sensing devices because magnetoresistive sensors operate in saturation mode. In particular, although AMR-based sensors provide measurement results with as small an angular error as possible (e.g., <0.2°), however, the sensor has unambiguous measurement results only within an angular range of 180°.

[0119] To solve this situation, it is proposed to combine the AMR-based sensor 110 operating in saturation mode with at least one Hall effect element 120, and in particular with a vertical Hall effect element 120 operating in linear mode. Here, the term "vertical" relates to the chip plane of the AMR-based sensor 110.

[0120] For further elaboration, reference is made again at this point to Figure 2 . Figure 2An embodiment of an angle sensor system 100 with an AMR-based sensor 110 is shown. As shown here merely by way of example, the AMR-based sensor 110 may include a plurality of sensor bridges 111, 112, ..., 118. The AMR-based sensor 110 is arranged in a main extension plane, the so-called chip plane (here: parallel to the drawing plane in the top view shown). The angle sensor system 100 further includes a first vertical Hall effect sensor 120. The first vertical Hall effect sensor 120 is arranged perpendicular to the chip plane of the AMR-based sensor 110. Optionally, the angle sensor system 100 may include a second vertical Hall effect sensor 121. The second vertical Hall effect sensor 121 is also arranged perpendicular to the chip plane of the AMR-based sensor 110.

[0121] The first Hall effect sensor 120 and / or the second Hall effect sensor 121 may be arranged laterally near the AMR-based sensor 110, or above or below the AMR-based sensor 110. However, the first Hall effect sensor 120 and / or the second Hall effect sensor 121 may be arranged at any other location on the substrate 104.

[0122] According to conceivable embodiments, the first vertical Hall effect sensor 120 can be arranged perpendicularly, i.e. at an angle of 90°, relative to the second vertical Hall effect sensor 121. Since the vertical Hall effect sensors 120, 121 each have a determined preferred direction 140, 141 for determining the magnetic field, the respective preferred directions 140, 141 of the respective vertical Hall effect sensors 120, 121 can also be oriented perpendicularly, i.e. at an angle of 90°, relative to each other. The first vertical Hall effect sensor 120 can thus be sensitive, for example, in the x-direction, while the second vertical Hall effect sensor 121 can be sensitive in the y-direction. Thus, it can be particularly advantageous to determine the correct half-plane for unambiguously determining the output signal (angle measurement result) of the AMR-based sensor 110.

[0123] Therefore, by means of this 90° arrangement, it is also possible to use the first vertical Hall effect sensor 120 and / or the second vertical Hall effect sensor 121 to unambiguously determine the corresponding half plane in the case of an angle measurement result of the AMR-based sensor 110. Thus, despite the use of the AMR-based sensor 110, the angle sensor system 100 can still provide unambiguous measurement results over an angle interval of 360°.

[0124] Thus, since the AMR-based sensor 110 outputs two ambiguous angular values within an angular range of 360°, the first vertical Hall effect sensor 120 and / or the second vertical Hall effect sensor 121 can be used to distinguish in which half-plane the AMR sensor 110 is currently operating.

[0125] In Figure 8 , the signal is plotted over the entire 360° rotation of the axis 102 ( Figure 1 ). It should be mentioned here that, for the sake of the explanations described here, a distinction is made between the so-called mechanical angle and the so-called electrical angle. The mechanical angle describes the real actual rotation of the rotor component 102. The electrical angle describes the angular signal of the sensor, i.e., the calculated angle output by the sensor. That is to say, although the rotor component can actually rotate a mechanical angle of 360°, the electrical angle measured by means of the AMR-based sensor 110 is unambiguous only within an angular range of 180°.

[0126] Figure 8 (The top column 1) shows the electrical angle, i.e., the measured angle, on the y-axis and the actual mechanical angle of the rotor component on the x-axis. It can be seen that there are two identical signals between 0° and 180° and between 180° and 360°. In the chart located below, the ideal output signals of an ideal first vertical Hall effect sensor (the top column 2) and an ideal second vertical Hall effect sensor arranged 90° offset therefrom (the top column 3) are shown. In the chart arranged below, the output signals of an actual first vertical Hall effect sensor (the top column 4) and an actual second vertical Hall effect sensor arranged 90° offset relative thereto (the top column 5) are shown.

[0127] The sensor signals shown here are discretized, for example, by means of a comparator function, where a positive signal provides a logic 0 at the output and a negative signal provides a logic 1 at the output. Since the Hall effect sensors have measurement signal deviations, the output signals from the two Hall effect sensors 120, 121 (X and Y) are used to determine the correct half-plane. In Figure 8 , the decision diagram is shown in the bottom row, based on which a decision is made as to which half-plane should be considered for angle measurement. Here, it is decided whether 180° should be added to the output signal of the AMR-based sensor. The following logic can be applied here:

[0128]

[0129] As long as the intersection of the outputs of the Hall sensor comparator function lies within the Hall sensor amplitude circuit, the method provides reliable results. This will be explained in more detail below with reference to Figure 9

[0130] Figure 9 A circle showing the limits (VHx and VHy) of the actual Hall sensor comparator function including an offset deviation. As long as the intersection point 190 is within the defined Hall sensor amplitude circuit 191, a reliable decision regarding the correct half-plane can be made.

[0131] Figure 10 An alternative embodiment for determining the correct half-plane is shown. Here, the full mechanical 360° rotation of the rotor component 102 is divided into a total of eight octants. Here, the 180° angle correction is also performed with the aid of Hall effect sensor signals (Xhall, Yhall), which can likewise be generated with the aid of a comparator function (only the coordinate system is Figure 9 different compared to).

[0132] Figure 10 The basic four octants of the semi-unit circle are shown, for which the AMR-based sensor signals can be reconstructed without problems. Thus, for example, the Hall effect sensor signal (Xhall) of a Hall effect sensor arranged in the X direction can be considered to be within the 2nd octant (between 0° and -45°) and the 3rd octant (between 0° and +45°). If the signal Xhall < 0, then 180° is added. On the other hand, for example, the Hall effect sensor signal (Yhall) of a Hall effect sensor arranged in the Y direction can be considered to be within the 1st octant (between -45° and -90°) and the 4th octant (between +45° and +90°). If the signal Yhall < 0, then 180° is added. To reconstruct the entire 360°, additional information can be utilized, such as information from a minimum vertical Hall effect-based angle sensor or a magnetic switch.

[0133] Below, the implementation of these correction angle calculations is illustrated with Python code: def cordic(vec_AMR,vec_VHall):

[0134] """Reconstruct the magnetic angle from the AMR and minimum vertical Hall sensor signals.

[0135] Inputs:

[0136] vec_AMR... Output from the AMR-based angle sensor

[0137] vec_VHall... Output from the vertical Hall angle sensor (0 = Xhall, 1 = Yhall)

[0138] """

[0139] angle_AMR = np.rad2deg(np.arctan2(vec_AMR[1], vec_AMR[0])) #[°]; from -180° to 180°

[0140] octant1 = (angle_AMR / 2 < -45) # Depends on VHallY, if positive, add 180°

[0141] octant2 = (-45 <= angle_AMR / 2) & (angle_AMR / 2 < 0) # Depends on VHallX, if negative, add 180°

[0142] octant3 = (0 <= angle_AMR / 2) & (angle_AMR / 2 < 45) # Depends on VHallX, if negative, subtract 180°

[0143] octant4 = (45 <= angle_AMR / 2) # Depends on VHallY, if negative, subtract 180°

[0144] angle_out = angle_AMR / 2

[0145] angle_out[octant1 & (vec_VHall[1] > 0)] += 180

[0146] angle_out[octant2 & (vec_VHall[0] < 0)] += 180

[0147] angle_out[octant3 & (vec_VHall[0] < 0)] -= 180

[0148] angle_out[octant4 & (vec_VHall[1] < 0)] -= 180

[0149] return angle_out

[0150] As long as the initial rotation can be guaranteed, for example, this is also used for the start-up calibration of amplitude and offset, the second channel (VH X) of the Hall effect sensor can be ignored. Here, the decision point of the half-plane is when the AMR intersects its 180° corner point.

[0151] Perform limited numerical simulations to verify these methods described herein to prove the feasibility of the scheme. For this purpose, the sensor architecture proposed herein was simulated in Python.

[0152] First, generate a rotating magnetic field with a typical amplitude. This magnetic field passes through two analytical sensor models ( Figure 11) Measured by a high-precision AMR-based angular sensor (0.05° angular noise and 180° periodicity of the output signal) and a perpendicular Hall-effect switch (error corresponding to 10° angular noise of the output signal, 360° periodicity, 1-bit output for each of the two output channels). Figure 11 (Top) shows the output signal of the AMR-based angular sensor, and Figure 11 (Bottom) shows the output signal of the perpendicular Hall-effect switch as a function of the true mechanical angle of the rotating magnetic field.

[0153] These output signals have been processed with the general CORDIC functions (vec_AMR, vec_VHall), see above. The reconstructed angles are plotted in Figure 12 . Here, the angular error 151 of the angle reconstructed with the perpendicular Hall-effect switch and the angular error 152 of the combination formed by the AMR-based sensor and the perpendicular Hall-effect switch can be seen. Although the output signal of the perpendicular Hall-effect switch is not perfect, the reconstruction of the correct octant is correct for each sampling point.

[0154] The innovative solution described herein can be used in any system solution that utilizes a discrete Hall-effect sensor in combination with an AMR-based sensor. In this case, it is advantageous that the Hall-effect sensor chip is arranged as close as possible to the AMR sensor chip.

[0155] Therefore, with this solution, the correct 180° half-plane of the angular output signal of the AMR-based angular sensor can be unambiguously determined, more precisely, the correct 180° half-plane can be unambiguously determined when using at least one and preferably two perpendicular Hall-effect sensors 120, 121 arranged orthogonally to each other in combination with the AMR-based sensor 110.

[0156] The above embodiments are only illustrative of the principles of the innovative solution described herein. It should be understood that modifications and variations of the arrangements and details described herein will be apparent to other persons skilled in the art. Therefore, it is intended that the solution described herein be limited only by the scope of the appended patent claims and not by the specific details presented in the description and illustration of the embodiments herein.

[0157] Although some aspects are described in connection with a device, it should be understood that these aspects also describe the corresponding method, so that a block or structural element of the device can also be understood as a corresponding method step or a feature of a method step. Similarly, aspects described in connection with method steps or as method steps also represent a description of the corresponding block or detail or feature of the corresponding device.

[0158] Some or all of the method steps in the method steps may be performed by (or using) a hardware device, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the most important method steps may be performed by such a device.

[0159] According to the determined implementation requirements, an embodiment can be implemented in hardware, in software, or at least partially in hardware or at least partially in software. The implementation can be performed in the case of using a digital storage medium, such as a floppy disk, a DVD, a Blu-ray disc, a CD, a ROM, a PROM, an EPROM, an EEPROM, or a flash memory, a hard disk, or other magnetic or optical memories, on which an electronically readable control signal is stored, which interacts or can interact with a programmable computer system such that the corresponding method is performed. Thus, the digital storage medium can be computer-readable.

[0160] Some embodiments also include a data carrier having an electronically readable control signal that can interact with a programmable computer system such that one of the methods described herein is performed.

[0161] Generally, an embodiment can be implemented as a computer program product having program code, where when the computer program product runs on a computer, the program code effectively performs one of the methods.

[0162] The program code can also be stored, for example, on a machine-readable carrier.

[0163] Other embodiments include a computer program for performing one of the methods described herein, where the computer program is stored on a machine-readable carrier. In other words, the embodiments of the methods described herein are thus computer programs that have program code that, when the computer program runs on a computer, is used to perform one of the methods described herein.

[0164] Thus, another embodiment of the methods described herein is a data carrier (or a digital storage medium or a computer-readable medium) on which a computer program for performing one of the methods described herein is recorded. The data carrier or digital storage medium or computer-readable medium is generally tangible and / or non-transitory.

[0165] Thus, another embodiment of the methods described herein is a data stream or a signal sequence that represents a computer program for performing one of the methods described herein. The data stream or signal sequence can be configured, for example, to be transmitted via a data communication connection, such as via the Internet.

[0166] Another embodiment includes a processing device, such as a computer or a programmable logic component, configured or adapted to perform one of the methods described herein.

[0167] Another embodiment includes a computer on which a computer program for performing one of the methods described herein is installed.

[0168] Another embodiment includes a device or system designed to transmit to a receiver a computer program for performing at least one of the methods described herein. The transmission can be carried out, for example, electronically or optically. The receiver can be, for example, a computer, a mobile device, a storage device or a similar device. The device or system can include, for example, a file server for transmitting the computer program to the receiver.

[0169] In some embodiments, programmable logic components (such as field programmable gate arrays, FPGAs) can be used to perform some or all of the functions of the methods described herein. In some embodiments, a field programmable gate array can cooperate with a microprocessor to perform one of the methods described herein. Generally, in some embodiments, these methods are performed in terms of any hardware device. The hardware device can be general-purpose hardware, such as a computer processor (CPU), or hardware dedicated to the method, such as an ASIC.

[0170] The above embodiments are merely illustrative of the principles of the solutions described herein. It should be understood that modifications and variations of the arrangements and details described herein will be apparent to other persons skilled in the art. Accordingly, it is intended that the solutions described herein be limited only by the scope of the appended patent claims and not by the specific details presented in the description and illustration of the embodiments herein.

Claims

1. A magnetic field-based angle sensor system (100), comprising: A stator component (104) and a rotor component (102) rotatable relative to the stator component, wherein the rotor component (102) has a multi-pole magnet (101), A magnetic field sensor (110) operating in saturation mode and a magnetic field sensor (120) operating in linear mode, Wherein the magnetic field sensor (110) operating in saturation mode is designed to determine the rotation angle of the rotor component (102) relative to the stator component (104) based on the magnetic field of the multi-pole magnet (101), and Wherein the magnetic field sensor (120) operating in linear mode is designed to measure the external stray magnetic field acting on the angle sensor system (100), and Wherein the angle sensor system (100) further has a control device (130), which is designed to: based on the external stray magnetic field measured by the magnetic field sensor (120) operating in linear mode, compensate for the measurement deviation related to the stray field in the determination of the rotation angle performed by the magnetic field sensor (110) operating in saturation mode.

2. The magnetic field-based angle sensor system (100) according to claim 1, Wherein the magnetic field sensor (110) operating in saturation mode has a magnetoresistive sensor that uses the anisotropic magnetoresistive effect AMR, giant magnetoresistive effect GMR, or colossal magnetoresistive effect CMR, or magnetic tunnel resistance effect TMR.

3. The magnetic field-based angle sensor system (100) according to claim 1 or 2, Wherein the magnetic field sensor (120) operating in linear mode has a Hall effect sensor.

4. The magnetic field-based angle sensor system (100) according to claim 3, Wherein the Hall effect sensor (120) is designed as a vertical Hall effect plate arranged perpendicular to the magnetic field sensor (110) operating in saturation mode.

5. The magnetic field-based angle sensor system (100) according to claim 1 or 2, Wherein the control device (130) is designed to perform automatic calibration (320) of the output signal (310) of the magnetic field sensor (120) operating in linear mode, so as to obtain a compensation parameter (330) related to the stray field, and the compensation parameter related to the stray field describes the external stray magnetic field. The compensation parameter (330) related to the stray field includes offset information (Ox, Oy) and / or amplitude information (Ax, Ay) of the output signal (310) of the magnetic field sensor (120) operating in linear operation.

6. The magnetic field-based angle sensor system (100) according to claim 5, wherein the compensation parameter (330) related to the stray field has a ratio between the offset information (Ox, Oy) and the amplitude information (Ax, Ay) according to the following formula: Offset information (x; y) / Amplitude information (x; y) = (Ox / Ax; Oy / Ay).

7. The magnetic field-based angle sensor system (100) according to claim 5, wherein the control device (130) is designed to perform an angle calculation based on the output signal (340) of the magnetic field sensor (110) operating in saturation operation, the angle calculation indicating the rotational angle of the rotor component (102) relative to the stator component (104), and wherein the control device (130) is designed to apply the compensation parameter (330) related to the stray field to the output signal (340) of the magnetic field sensor (110) operating in saturation operation before the angle calculation, so as to compensate for the measurement deviation when determining the rotational angle thereby.

8. The magnetic field-based angle sensor system (100) according to claim 5, wherein the control device (130) is designed to perform an angle calculation based on the output signal (340) of the magnetic field sensor (110) operating in saturation operation, the angle calculation indicating the rotational angle of the rotor component (102) relative to the stator component (104), and wherein the control device (130) is designed to apply the compensation parameter (330) related to the stray field to the result of the angle calculation after the angle calculation, so as to compensate for the measurement deviation when determining the rotational angle thereby.

9. The magnetic field-based angle sensor system (100) according to claim 7, wherein the control device (130) is designed to perform amplitude-phase-offset-correction (360) of the output signal (340) of the magnetic field sensor (110) operating in saturation operation before applying the compensation parameter (330) related to the stray field, In the amplitude-phase-offset-correction (360), amplitude shift compensation and / or phase shift compensation and / or offset compensation is applied to the output signal (340) of the magnetic field sensor (110) operating in saturation operation.

10. A method for compensating measurement deviations when determining a rotational angle by means of a magnetic-field-based angle sensor system (100), the method comprising the following steps: A stator component (104) and a rotor component (102) rotatable relative to the stator component are provided, wherein the rotor component (102) has a multi-pole magnet (101). A magnetic field sensor (110) operating in saturation operation and a magnetic field sensor (120) operating in linear operation are provided. By means of the magnetic field sensor (110) operating in saturation operation, the rotation angle between the rotor component (102) and the stator component (104) is determined based on the magnetic field of the multi-pole magnet (101). By means of the magnetic field sensor (120) operating in linear operation, an external stray magnetic field acting on the angle sensor system (100) is determined, and a measurement deviation related to the stray field is compensated when determining the rotation angle based on the determined stray magnetic field.

11. The method according to claim 10, performing an automatic calibration (320) of the output signal (310) of the magnetic field sensor (120) operating in linear operation in order to thereby determine compensation parameters (330) related to stray fields, the compensation parameters related to stray fields describing an external stray magnetic field, wherein the compensation parameters (330) related to stray fields comprise offset information (Ox, Oy) and / or amplitude information (Ax, Ay) of the output signal (310) of the magnetic field sensor (120) operating in linear operation.

12. The method according to claim 11, performing an angle calculation based on the output signal (340) of the magnetic field sensor (110) operating in saturation operation, the angle calculation indicating the rotational angle of the rotor component (102) relative to the stator component (104); and applying the compensation parameters (330) related to stray fields to the output signal (340) of the magnetic field sensor (110) operating in saturation operation before the angle calculation in time in order to thereby compensate the measurement deviation when determining the rotational angle.

13. The method according to claim 11, performing an angle calculation based on the output signal of the magnetic field sensor (110) operating in saturation operation, the angle calculation indicating the rotational angle of the rotor component (102) relative to the stator component (104), and applying the compensation parameters (330) related to stray fields to the result of the angle calculation after the angle calculation in time in order to thereby compensate the measurement deviation when determining the rotational angle.

14. The method according to claim 12 or 13, Before applying the compensation parameter (330) related to the stray field in time, perform automatic calibration (361) of the output signal (340) of the magnetic field sensor (110) operating in saturation operation, wherein amplitude shift compensation and / or phase shift compensation and / or offset compensation is applied to the output signal (340) of the magnetic field sensor (110) operating in saturation operation in the automatic calibration (361).

15. A computer program product having program code for performing the method according to claim 14 when the program is run on a computer.

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