阅读说明：本技术 具有两个偏移布置的拾波线圈组件的感应角度传感器 (Inductive angle sensor with two offset pick-up coil assemblies ) 是由 U·奥塞勒克纳 于 2021-05-17 设计创作，主要内容包括：本公开的各实施例涉及具有两个偏移布置的拾波线圈组件的感应角度传感器。本文所述的创新概念涉及一种感应角度传感器。该感应角度传感器包括具有k重对称性的感应目标组件以及具有k重对称性的第一拾波线圈组件和具有k重对称性的第二拾波线圈组件。组合装置被设计为将第一拾波线圈组件的信号与第二拾波线圈组件的信号组合,并且基于此来求取角度误差补偿后的旋转角度。第一拾波线圈组件的拾波单线圈和第二拾波线圈组件的拾波单线圈分别相对于彼此绕旋转轴线R以旋转方式偏移了几何偏移角α。另外,整个第一拾波线圈组件相对于整个第二拾波线圈组件绕旋转轴线R以旋转方式偏移了几何偏移角ρ。(Embodiments of the present disclosure relate to an inductive angle sensor having two pick-up coil assemblies arranged offset. The inventive concepts described herein relate to an inductive angle sensor. The inductive angle sensor includes an inductive target assembly having k-fold symmetry, and a first pickup coil assembly having k-fold symmetry and a second pickup coil assembly having k-fold symmetry. The combination means are designed to combine the signal of the first pickup coil assembly with the signal of the second pickup coil assembly and to determine the angle error compensated rotation angle on the basis thereof. The pickup single coil of the first pickup coil assembly and the pickup single coil of the second pickup coil assembly are respectively rotationally offset relative to each other about the rotation axis R by a geometric offset angle α. In addition, the entire first pickup coil assembly is rotationally offset about the rotation axis R by a geometric offset angle ρ relative to the entire second pickup coil assembly.)

1. An inductive angle sensor (100) having:

a stator and a rotor rotatable relative to the stator about a rotational axis R, wherein the rotor comprises an induction target assembly (101) having k-fold symmetry, and wherein the stator comprises a first pick-up coil assembly (110) having k-fold symmetry and a second pick-up coil assembly (120) having k-fold symmetry,

wherein the first (110) and the second (120) pick-up coil assembly are each arranged around the rotation axis R and each have the same number of pick-up single coils (111, 112, 113; 121, 122, 123),

wherein the pickup single coils (111, 112, 113) of the first pickup coil assembly (110) are rotationally offset relative to each other about the rotation axis R by a geometric offset angle a, and wherein the pickup single coils (121, 122, 123) of the second pickup coil assembly (120) are rotationally offset relative to each other about the rotation axis R by the same geometric offset angle a,

wherein in case the pick-up coil assembly (110, 120) has an even number of pick-up single coils (111, 112; 121, 122), said offset angle α is calculated as follows:

α is 360 °/k/M/2, and

wherein in case the pick-up coil assembly (110, 120) has an odd number of pick-up single coils (111, 112, 113; 121, 122, 123), said offset angle α is calculated as follows:

α＝360°/k/M，

wherein M represents the number of pickup single coils (110, 120) present in each pickup coil assembly (110, 120),

a combining means (130) designed to perform a signal combination, wherein the signal of the first pickup coil assembly (110) is combined with the signal of the second pickup coil assembly (120) to find based thereon an angle of rotation (phi') between the stator and the rotor after the angular error compensation, and

wherein the entire first pickup coil assembly (110) is rotationally offset about the rotation axis R by a geometric offset angle p relative to the entire second pickup coil assembly (120).

2. Inductive angle sensor (100) according to claim 1,

wherein the geometric deviation angle rho is less than or equal to alpha.

3. Inductive angle sensor (100) according to claim 1 or 2,

wherein the geometric offset angle ρ ═ α × n/4, where n is an integer greater than 1.

4. Inductive angle sensor (100) according to claim 3,

wherein if the signal combining comprises: firstly combining the output signals respectively induced in the pick-up coil assemblies (110, 120) with one another, and then determining the angle error-compensated rotation angle (phi') between the stator and the rotor based on this combination of the induced output signals, n being 3, or

Wherein if the signal combining comprises: -first finding a single rotation angle signal (phi1', phi2') specific to the respective pickup coil assembly (110, 120) for the output signals induced in the pickup coil assembly (110, 120), respectively, and then combining the single rotation angle signals (phi1', phi2') with each other to find the angle error compensated rotation angle (phi ') between the stator and the rotor based on the combination of the single rotation angle signals (phi1', phi2'), then n being 2.

5. Induction angle sensor (100) according to any of claims 1 to 4,

wherein the combination device (130) is designed to: -determining the angle error compensated rotation angle (phi') between the stator and the rotor based on averaging the signal of the first pick-up coil assembly (110) and the signal of the second pick-up coil assembly (120) offset by the offset angle p.

6. Induction angle sensor (100) according to any of claims 1 to 5,

wherein the signal of the first pickup coil assembly (110) and the signal of the second pickup coil assembly (120) are respectively amplitude-modulated high-frequency output signals of the respective pickup coil assemblies (110, 120), wherein the amplitude of the carrier frequency of the respective high-frequency output signals varies depending on the position between the stator and the rotor, or

Wherein the signal of the first pickup coil assembly (110) and the signal of the second pickup coil assembly (120) are demodulated signals of the amplitude-modulated high frequency output signals of the respective pickup coil assembly (110, 120), wherein each demodulated signal describes an envelope of one of the amplitude-modulated high frequency output signals, respectively.

7. Induction angle sensor (100) according to any of claims 1 to 6,

wherein the combination device (130) is designed to:

deriving a first angle signal (phi1') based on the signal of the first pickup coil assembly (110), the first angle signal being indicative of the position of the target assembly (101) relative to the first pickup coil assembly (110), and

deriving a second angle signal (phi2') based on the signal of the second pickup coil assembly (120), the second angle signal being indicative of the position of the target assembly (101) relative to the second pickup coil assembly (120), and

generating a combined angle signal (phi _ new ') describing the angle error compensated rotational angle (phi') between the stator and the rotor based on averaging the first angle signal (phi1') and the second angle signal (phi 2').

8. Induction angle sensor (100) according to any of claims 1 to 7,

wherein the combining means (130) has a first circuit, a second circuit and a third circuit,

wherein the first circuit is connected to the first pickup coil assembly (110) and is designed to calculate the first angle signal (phi1'),

wherein the second circuit is connected to the second pickup coil assembly (120) and is designed to calculate the second angle signal (phi2'), and

wherein the third circuit is designed to: combining the first angle signal (phi1') and the second angle signal (phi2') with each other to find the angle of rotation (phi) between the stator and the rotor compensated for the angular error based thereon.

9. Induction angle sensor (100) according to any of claims 1 to 7,

wherein the combination device (130) has a circuit which is designed to: determining the first angle signal (phi1') and the second angle signal (phi2') by applying a time division multiplexing method, wherein

In a first time interval, calculating at least one signal component of the first angle signal (phi1') based on the signal of the first pickup coil assembly (110), and wherein

Calculating at least one signal component of the second angle signal (phi2') based on the signal of the second pickup coil assembly (120) in a second, different time interval.

10. Induction angle sensor (100) according to any of claims 1 to 7,

wherein the first (110) and second (120) pickup coil assemblies are electrically coupled to each other and form one or more pickup single coil pairs (U, V, W), wherein in each pickup single coil pair (U, V, W) one of the pickup single coils (111, 112, 113) of the first pickup coil assembly (110) is connected in series or in parallel with one pickup single coil (121, 122, 123) of the second pickup coil assembly (120) that is offset with respect to that pickup single coil by the geometric offset angle p, respectively, and

wherein the combination device (130) is designed to: the angle error-compensated rotation angle (phi') between the stator and the rotor is determined based on a combination of the signals of the respectively connected pickup single coils (111, 112, 113; 121, 122, 123) of the one or more pickup single coil pairs (U, V, W).

11. Inductive angle sensor (100) according to claim 10,

wherein each signal of a first pick-up single coil (111) of a pick-up single coil pair (U) respectively combines as a result of said electrical coupling with a signal of a second pick-up single coil (121) of the same pick-up single coil pair (U) connected together with said first pick-up single coil into a common coil pair output signal, and

wherein the combination device (130) has a circuit which is designed to: -combining respective coil pair output signals of the one or more pickup single coil pairs (U, V, W) with each other to find the angular error compensated rotational angle (phi) between the stator and the rotor based thereon.

12. Inductive angle sensor (100) according to claim 10 or 11,

wherein the combination device (130) is designed to: the angle error compensated rotation angle between the stator and the rotor is found based on averaging the signals of the respective mutually interconnected pickup single coils (111, 112, 113; 121, 122, 123) of the one or more pickup single coil pairs (U, V, W).

13. Inductive angle sensor (100) according to one of claims 1 to 10,

wherein the control device has a first circuit and a second circuit,

wherein the first circuit is connected to a pick-up single coil (111) of the first pick-up coil assembly (110) and is designed to process a signal of this pick-up single coil (111) and to find a first single-coil output signal (U1), and

wherein the second circuit is connected to a pick-up single coil (121) of the second pick-up coil assembly (120) and is designed to process the signal of the second pick-up single coil (121) and to find a second single-coil output signal (U2), and

wherein the combination device (130) is designed to: -combining the respective first single-coil output signal (U1) and the second single-coil output signal (U2) with each other to find the angle of rotation between the stator and the rotor compensated for the angular error based thereon.

14. Inductive angle sensor (100) according to one of claims 1 to 13,

wherein the stator has a substrate on which the first pick-up coil assembly (110) and the second pick-up coil assembly (120) are commonly arranged.

15. Inductive angle sensor (100) according to claim 14,

wherein the substrate has at least two metallization layers spaced apart from each other,

wherein the pick-up single coils (111, 112, 113) of the first pick-up coil assembly (110) are alternately designed in the metallization layers of the substrate spaced apart from each other, and

wherein the pick-up single coils (121, 122, 123) of the second pick-up coil assembly (120) are also alternately designed in the metallization layers of the substrate spaced apart from one another and are here offset by the geometric offset angle p with respect to the pick-up single coils (111, 112, 113) of the first pick-up coil assembly (110).

Technical Field

The inventive concepts described herein relate to an inductive angle sensor, and in particular to an inductive angle sensor with integrated compensation of a system error band when determining an angle of rotation between a stator and a rotor. To this end, the inductive angle sensor has a stator with a first pickup coil assembly and a substantially identical second pickup coil assembly, wherein the two pickup coil assemblies are arranged offset with respect to one another by a defined rotation angle.

Background

An induction angle sensor usually has a stator and a rotor which can be rotated relative to the stator. In order to make the rotor rotatable relative to the stator, a slight air gap (so-called Airgap) is present between the rotor and the stator. The stator may for example be implemented as a Printed Circuit Board, abbreviated as PCB (english: Printed Circuit Board). An excitation coil may be disposed on the stator. An input signal, for example an ac signal, is fed to the excitation coil. In response, the field coil generates a magnetic field that is decoupled from the field coil. The opposing rotors have an inductive target into which a magnetic field is coupled. In response, the inductive target generates eddy currents, which in turn generate a secondary magnetic field that is decoupled from the inductive target. The secondary magnetic field is then coupled into a pick-up coil assembly arranged on the stator. In response, the pick-up coil assembly generates an output signal representative of the angle between the stator and the rotor.

The target at the rotor and the pick-up coil at the stator are coordinated with each other. Both have a specific symmetry in harmony with each other. That is, the target and the pick-up coil may have a certain symmetrical shape. For example, similar to the incremental wheel, the target may have the shape of teeth and gaps, and the pick-up coil may for example have symmetrical windings. In the context of the present disclosure, this symmetry is also referred to as k-fold symmetry. If such a k-fold symmetry is mentioned in this context, it is to be understood as a rotationally or rotationally symmetrical form. For example, an object has k-fold symmetry if it can be rotated 360 ° n/k around an axis such that the object appears the same after rotation as before rotation (where n is an arbitrary Integer (Integer)). In addition, in the present disclosure, the k-fold symmetry is characterized by: in the case of k-fold symmetry, if the coil (or target) is rotated 360 °/k, the signal induced in the coil (or target) remains the same.

The aforementioned output signal induced in the pick-up coil assembly may be an alternating voltage signal consisting of a high frequency HF carrier component and a low frequency LF signal component. However, it may happen that such LF signal components do not vary in an ideal sinusoidal fashion with the angle of rotation between the stator and the rotor. As a result, systematic errors, or rather systematic error bands, occur, which lead to systematic deviations in the accuracy of the angle measurement. The systematic errors are present in the small harmonic content of the LF signal components, i.e. their second, third, fourth, etc. harmonics, wherein the dominant fundamental wave (first harmonic) corresponds to the angle of rotation (or k times the angle of rotation in the case of multiple symmetry k >1 of the target).

One possible solution to correct such system errors is to: very special coil geometries are provided in combination with highly accurately manufactured targets and precisely known air gaps in order to thereby obtain an ideal sinusoidal signal with respect to the angle of rotation. However, complex coil geometries are required for this purpose, which leads to increased production costs.

Another possible solution to correct the systematic error is: a corresponding mathematical correction formula or a corresponding look-up table is provided, each describing the angular error of the system. In this case, such an angle sensor may first calculate the angle of rotation, then determine the angle deviation or the corresponding correction factor stored for this from a formula or table, and then recalculate the actual angle of rotation taking into account the angle deviation or the correction factor. However, this only applies to a single predefined air gap. Once the air gap changes, for example due to tolerances in the assembly, the look-up table or mathematical correction formula must also be modified accordingly. Therefore, a two-dimensional correction table for the angle error, which in turn depends on the true angle of rotation and the actual air gap, has to be prepared for such a system. Furthermore, the air gap must always be known very precisely, which is generally not known precisely, in particular in mass-produced angle sensors.

It is therefore desirable to provide an inductive angle sensor which can compensate or correct for systematic angle errors and which nevertheless allows a simple coil geometry and responds to air gap fluctuations without being susceptible to disturbances and at the same time can provide an accurate angle signal here for substantially any design objective.

Disclosure of Invention

An induction angle sensor having the features according to the invention is therefore proposed. Embodiments and further advantageous aspects of the induction angle sensor are given in the respective dependent claims.

The inventive inductive angle sensor described herein has, inter alia, a stator and a rotor which is rotatable relative to the stator about a rotational axis, wherein the rotor comprises an inductive target assembly with k-fold symmetry, and wherein the stator comprises a first pick-up coil assembly with k-fold symmetry and a second pick-up coil assembly with k-fold symmetry. The first and second pickup coil assemblies are respectively arranged around the rotation axis R and respectively have the same number of pickup single coils. The pick-up single coils of the first pick-up coil assembly are rotationally offset relative to each other about the rotation axis R by a geometric offset angle a, and the pick-up single coils of the second pick-up coil assembly are rotationally offset relative to each other about the rotation axis R by the same geometric offset angle a. In the case where the pickup coil assembly has an even number of pickup single coils, the offset angle α is calculated as follows:

α＝360°/k/M/2。

in the case where the pickup coil assembly has an odd number of pickup single coils, the offset angle α is calculated as follows:

α＝360°/k/M。

the variable M represents the number of pickup single coils present in each pickup coil assembly. The angle sensor also has a combination device, which is designed to carry out a signal combination in which the signal of the first pickup coil arrangement is combined with the signal of the second pickup coil arrangement in order to determine the angle of rotation between the stator and the rotor after the angular error compensation on the basis thereof. In addition, according to the innovative concept described herein, the entire first pickup coil assembly is rotationally offset about the rotation axis R by a geometric offset angle ρ with respect to the entire second pickup coil assembly. The first and second pickup coil assemblies have the same number of pickup single coils, respectively. The first pick-up coil assembly generates a plurality of signals, at least two of which have a phase shift of 360/M at its first harmonic after demodulation. The second pickup coil arrangement generates the same number of signals, wherein here again at least two signals after demodulation have a phase shift of 360 °/M at their first harmonic.

Drawings

Some embodiments are exemplarily shown in the drawings and explained below. Wherein:

figure 1A shows a schematic perspective view of a model of an inductive angle sensor with a single pick-up coil assembly according to one embodiment,

figure 1B shows a schematic top view of a model of two pickup coil assemblies arranged offset with respect to each other according to one embodiment,

figure 1C shows a schematic perspective view of a model of an induction angle sensor with two pick-up coil assemblies arranged offset to each other according to one embodiment,

figure 2A shows a schematic top view of a model of an omnidirectional pick-up single coil according to one embodiment,

figure 2B shows a schematic top view of a model of two non-directional pickup single coils arranged offset with respect to each other according to one embodiment,

figure 3A shows a graph showing the maximum angular error in terms of the offset angle p (rho) between the two pick-up coil assemblies,

figure 3B illustrates a graph showing compensation for systematic angle error according to the concepts described herein,

fig. 4 shows a schematic top view of a model of two non-omnidirectional pickup single coils arranged offset with respect to each other and electrically connected together, according to one embodiment.

Figure 5 shows a diagram for illustrating the degree of coverage of a single pick-up single coil in unconnected components and in interconnected components,

figures 6A to 6C show diagrams for illustrating the extent of coverage of the approximately sinusoidal shape of the pick-up coil surface,

figure 7 shows a schematic view of an inductive angle sensor with an omnidirectional pick-up coil,

figure 8 shows a graphical representation of the signal curve over time for an M-phase system with an omnidirectional coil of a rapidly rotating target,

fig. 9 shows a schematic top view of a model of a non-omnidirectional pick-up coil assembly, having three non-omnidirectional pick-up single coils arranged offset from each other,

figure 10 shows a graphical representation of the signal curve over time for a three-phase system with a non-directional coil of a rapidly rotating target,

figure 11 shows a schematic top view of a model of a non-omnidirectional pick-up single coil and its implementation in different metallization layers of a substrate,

figure 12 shows a top view of a target assembly embedded in a plastic matrix,

FIG. 13 shows a schematic top view of a model of the target assembly, an

Fig. 14 shows a graphical representation of the curve shape of the system angle error band.

Detailed Description

Embodiments are explained in more detail below with reference to the drawings, wherein elements having the same or similar function are provided with the same reference numerals.

If reference is made here to k-fold symmetry, this is to be understood as a rotationally symmetrical or rotationally symmetrical form. An object has k-fold symmetry if it can be rotated 360 deg. n/k around an axis such that the object appears the same after rotation as before rotation (where n is an arbitrary Integer). In addition, in the present disclosure, the k-fold symmetry is characterized by: in the case of k-fold symmetry, if the coil (or target) is rotated 360 °/k, the signal induced in the coil (or target) remains the same.

If values for the angles are specified herein, these values also apply within a tolerance of + -10% or + -1 deg.. This means that the inventive concept described herein may provide satisfactory results even if the angles mentioned herein deviate within a range of ± 10% or ± 1 °.

First, to introduce the problems underlying here, an inductive angle sensor with a single pick-up coil assembly will be discussed. Fig. 7 shows a schematic view of such an inductive angle sensor 700.

The angle sensor 700 has an excitation coil 701 and a single pickup coil assembly 702, the single pickup coil assembly 702 having two pickup single coils 703, 704 which are offset from each other. The excitation coil 701 and the pickup coil assembly 702 are typically arranged on a stator (not explicitly shown here). In addition, angle sensor 700 also has a sensing target 705. The target 705 is typically arranged on a rotor (not explicitly shown here).

The target 705 may be made of an electrically conductive material and may, for example, be designed as a stamped metal profile with a thickness d. Instead of a solid (massiv) metal profile, the target can also be designed in the form of a rotor coil. In this case, the rotor coil can have substantially the geometry of a metal profile and can behave like a short-circuited coil.

The target 705 may have k-fold symmetry. In this example, the target 705 has 3-fold symmetry with three teeth 705A and three gaps 705B, respectively. The gaps 705B between the teeth 705A do not necessarily have to have the same shape as the teeth 705A themselves. Tooth 705A has a span s at the outer radius.

The pickup single coils 703, 704 at the stator may be adapted to the inductive target 705 at the rotor. That is, the pick-up single coils 703, 704 may have k-fold symmetry that matches the k-fold symmetry of the target 705. In this example, the two pickup monocoils 703, 704 each have 3-fold symmetry, with each two adjacent windings 703A, 703B belonging in common to one pickup monocoil 703. In this case, each two adjacent windings 703A, 703B have an opposite orientation, i.e. they are each wound in opposite directions to one another, in order to compensate for the homogeneous external magnetic field (interference field) and the symmetrical interference field of the excitation coil 701. Therefore, these pickup single coils 703, 704 are also referred to as being non-directional.

The non-directional pick-up coil is particularly characterized in that it has an even number of windings, wherein the even number of windings are wound in a first winding direction (e.g. in a clockwise direction) and the odd number of windings respectively located between these even number of windings are wound in an opposite second winding direction (e.g. in a counter-clockwise direction). This would result in the first half of the omnidirectional pick-up single coil providing a first signal in the case of a homogeneous disturbing magnetic field and the second half of the omnidirectional pick-up single coil providing a second signal, wherein the second signal is in anti-phase with the first signal due to the opposite winding direction. The same applies in this example to the second omnidirectional pickup single coil shown here, the first half of which provides the third signal in this example and the second half of which provides the fourth signal in anti-phase due to the opposite winding direction. Based on this arrangement of the phase opposition, the induced signals, which can be attributed to the spatially constant interference field, cancel each other out.

With regard to the definition of the important k-fold symmetry in the present disclosure, the following points should also be pointed out in this regard. As described above, each of the pickup single coils 703, 704 shown in fig. 7 has 3-fold symmetry, respectively. The 3-fold symmetry is explained below using a single pick-up single coil (e.g., pick-up single coil 703) as an example. That is, if the pick-up single coil 703 shown here is rotated by 360 °/6 ═ 60 °, then although the respective conductor loops or windings of that pick-up single coil 703 will coincide again, in this case the orientation (winding direction) of each single loop or winding is reversed. Therefore, the pickup monocoil 703 must be rotated by 360 °/3 — 120 ° so that the single windings coincide again and also have the same orientation, so that the pickup monocoil 703 accordingly also provides the same signal again. Thus, the two pickup single coils 703, 704 shown have 3-fold symmetry (i.e. k 3), although they appear at first sight to have 6-fold symmetry (i.e. k 6).

Each of the pickup monocoils 703, 704 generates a respective output signal in response to the secondary magnetic field emanating from the target 705. The output signal may be an output voltage signal. These high frequency output signals are amplitude modulated and vary with the current rotational position of the rotor relative to the stator. These amplitude modulated HF signals can be demodulated. The demodulated LF signals of the two omnidirectional pick-up single coils 703, 704 are at least approximately sine-shaped or cosine-shaped, again depending on the angle of rotation of the rotor relative to the stator. Therefore, the omnidirectional pickup single coils 703, 704 are sometimes also referred to as sine pickup coils or cosine pickup coils. In this example, sine and cosine can of course be arbitrarily interchanged.

Further, the first pickup monocoil 703 and the second pickup monocoil 704 are also arranged offset from each other by the geometric offset angle α. The offset angle a depends on the variable k and the variable M of the k-fold symmetry of the pick-up single coils 703, 704. The variable M represents the number of pickup single coils 703, 704 that the pickup coil assembly 702 has. In principle, each of the pick-up single coils 703, 704 may generate an induced output signal separately. The output signal has a phase offset caused inter alia by the offset angle alpha. The variable M therefore also characterizes the number of induced output signals that each pick-up coil assembly can produce. This will also be discussed in more detail below.

Further, the windings 703A, 703B of the respective pickup monocoil 703 may also have a winding angle β.

The excitation coil 701 and the pickup monocoils 703, 704 are arranged rotationally symmetrically about a common axis of rotation R. Here, the excitation coil 701 is arranged in a loop around the pickup monocoils 703, 704.

Here, it should again be noted that the inductive angle sensor 700 shown here has a pickup coil assembly 702 comprising a plurality (here two) of pickup single coils 703, 704 which are rotated relative to each other about the rotation axis R by a geometric offset angle α. Each pick-up single coil 703, 704 has a plurality of windings 703A, 703B.

To operate the induction angle sensor 700, the excitation coil 701 may be applied with a sinusoidal voltage of approximately 1V at a frequency of 4MHz, for example. This generates an alternating magnetic field (primary magnetic field) in the excitation coil 701, which in turn generates eddy currents in the target 705. These eddy currents in turn generate a magnetic field (secondary magnetic field) on their side, which couples into the pick-up single coil 703, 704 and generates a corresponding voltage at the pick-up single coil. The voltage of the corresponding pickup single coil 703, 704 is measured. Since the voltage value depends on the position of the rotor relative to the stator, this voltage value can be used as a measure of the angle of rotation between the rotor and the stator. It is an amplitude modulated signal, i.e. it has a carrier frequency of 4MHz in this case, but its amplitude varies with the position of the rotor relative to the stator.

This will be explained in more detail below with reference to fig. 8. Fig. 8 shows an exemplary graph of the signal of a pick-up coil assembly with an even number of pick-up single coils (here M2), or of an M-phase system with an even number M (here M2), that is to say with 6-fold symmetry in the time domain, i.e. with k 6. Thus, the pickup coil assembly here is not the pickup coil assembly as shown in fig. 7, since the pickup coil assembly 702 shown in fig. 7 has 3-fold symmetry for the sake of clarity, i.e., k is 3. However, in contrast to the description of the signals shown in FIG. 8 below, reference is occasionally made to the apparatus and its reference numerals in FIG. 7.

As can be seen in fig. 8, the time is plotted on the abscissa, here for example between 0 μ s and 18 μ s. Curve 801 represents the eddy currents in the target 705, which are generated by the magnetic field of the excitation coil 701. Curve 801 oscillates at 1MHz and has a constant amplitude. In addition, curve 801 is zero-mean. In this example, it is assumed that the rotor rotates at a speed of 360 °/100 μ s, which corresponds to 6 × 10 per minute⁵Very high rotational speeds of the turns (this is only to clarify the signals in the graph).

Signals amU1 (curve 802) and amU2 (curve 803) represent the voltages induced in the two pickup single coils 703, 704. The voltages amU1, amU2 are amplitude modulated signals that are substantially zero mean. After demodulation of the respective amplitude-modulated signals amU1, amU2, for example by means of a phase-coherent demodulator, the respective envelopes of these signals amU1, amU2 (i.e. the "upper" parts of the amplitude-modulated signals amU1, amU 2) will be obtained. The envelope of signal amU1 is referred to herein as U1, and the envelope of signal amU2 is referred to herein as U2. This means that amplitude modulated high frequency HF signals amU1, amU2 are obtained before demodulation and low frequency LF signals U1, U2 are obtained after demodulation. As described above, after the LF signals U1, U2 are zero-mean, the LF signals U1, U2 are already stray field robust, i.e. non-directional, so that no further signal modification, e.g. by subtracting signal components, is required.

As can be seen from fig. 8, the demodulated LF signals U1, U2 are at least approximately sinusoidal or cosine-shaped, depending on the angle of rotation of the rotor relative to the stator. It should be clear, however, that the LF signals U1, U2 have small deviations from the ideal sinusoidal curve, which in the prior art would lead to systematic angular errors, and this would be largely eliminated by the innovative concept described herein.

The two envelopes (i.e. the demodulated LF signals U1, U2) may be generated, for example, by means of a phase-synchronized demodulator. The LF signals U1, U2 may then be correlated with the position of the rotor relative to the stator, so that the rotor position may be determined based on the demodulated LF signals U1, U2. This can be done by calculating the arctangent of the two LF signals U1, U2, which are phase-shifted from each other. A straight line 807 will be obtained as a result of the arctan calculation. The line 807 represents the electrical rotation angle shown herein, which is represented by curve 806.

Thus, the amplitude modulated HF signals amU1 (curve 802) and amU2 (curve 803) shown in fig. 8 may be voltages generated in two pickup single coils 703, 704 with 6-fold symmetry (k 6) rotated relative to each other by an offset angle α. Due to the rotation by the offset angle α, the two demodulated LF signals U1 (curve 804) and U2 (curve 805) are phase-shifted by 90 ° from each other in the so-called electrical angular domain.

It should be noted in this regard that two different phase shifts are shown in fig. 8. In one aspect, for amplitude modulated HF signals amU1, amU2 (see curves 802, 803), the phase shift is a phase shift with respect to time. On the other hand, for the baseband signals (i.e., demodulated LF signals U1, U2 (see curves 804, 805)), the phase shift is a phase shift with respect to the rotation angle. Thus, the signal varies with both time and the angle of rotation between the stator and the rotor. If a phase shift is mentioned in the present disclosure, the phase shift is a phase shift with respect to a rotation angle unless otherwise specified.

The two signals shown in fig. 8 are from a 2-phase system (M ═ 2). The two signals shown (i.e. the two amplitude modulated HF signals 802, 803 or the two demodulated LF signals 804, 805) indicate that the 2-phase system has two pick-up single coils. The pick-up single coil may be an omnidirectional pick-up single coil as exemplarily shown in fig. 7.

As described above, the variable M represents the number of pickup single coils present in each pickup coil assembly. Where M is even, exceptions may apply. This will be briefly explained below with reference to the device shown in fig. 7, in a theoretical example.

Thus, two additional pickup single coils 703x, 704x may also be added in the example shown in fig. 7, where the first additional pickup single coil 703x will be rotated 60 ° relative to the first pickup single coil 703, and where the second additional pickup single coil 704x will be rotated 60 ° relative to the second pickup single coil 704. However, the clockwise wound winding of the first pickup monocoil 703 would be directly opposite the counter-clockwise wound winding of the first additional pickup monocoil 703x, i.e. the first additional pickup monocoil 703x would generate a signal which differs only in sign from the signal generated by the first pickup monocoil 703. Therefore, this does not bring new angle information, so that the additional pickup single coil 703x can be omitted. This applies to all even numbers M. Thus, for even numbers M, M/2 pick-up single coils may be used, for the reasons mentioned above. Purely mathematically, two coils with different phases are also sufficient. That is, if the pick-up coil assembly has an even number of pick-up single coils, wherein the first half (M/2) of the pick-up single coils generates a first output signal, and wherein the second half (M/2) of the pick-up single coils generates a second signal that is inverted thereto, half of the M pick-up single coils (i.e., M/2) is sufficient to implement the inventive concepts described herein. While the other half (M/2) of the pick-up single coil present will be "redundant". In the sense of the present application, therefore, the special case of such a "redundant" pick-up single coil is included here, i.e. only half of the pick-up single coils present are counted in this case. Specifically, this means that the variable M is replaced by M/2 in the formulas described herein.

It should therefore be noted that not only is the example shown in fig. 7 a 2-phase system, i.e. M-2, but also the signal shown in fig. 8 is generated by a 2-phase system as well. However, since the two 2-phase systems have different k-fold symmetries (fig. 7: 3-fold symmetry; fig. 8: 6-fold symmetry), the periodicity of the signal in fig. 8 differs from the periodicity of the signal that can be generated by the apparatus in fig. 7.

This is in turn due to the fact that: the periodicity is related to the variable k of k-fold symmetry. That is, the signal shown in fig. 8 is from a system with 6-fold symmetry, i.e., k 6. It can be seen that the signal period extends 60 °, which is calculated as 360 °/k, where k is 6. Thus, the illustrated signal shape is repeated every 60 °, i.e. a total of six times over a full revolution of 360 °. While the example shown in fig. 7 has triple symmetry, i.e., k 3. Thus, the signal generated with the device shown in fig. 7 will have a periodicity of 360 °/3 — 120 °.

In addition, the waveforms shown and discussed in fig. 8 are also related to the electrical angular domain. The electrical angle range must in turn be distinguished from the mechanical angle range. If the rotor is actually (i.e. in the mechanical angular domain) rotated 360 ° relative to the stator, the rotor sweeps the windings of a pick-up single coil with k-fold symmetry a total of k times. Accordingly, such a pick-up single coil with k-fold symmetry also provides k periods accordingly, which then in turn will correspond to the electrical angular domain. That is, the electrical angular domain corresponds to k times the mechanical angular domain.

An induced angle sensor according to the inventive concept described herein can output an electrical angle because if a further 7 ° of rotation is added over, for example, three tooth cycles of the target 705, the induced angle sensor will output 7 ° instead of 3x 360 ° +7 ° (particularly when the circuit is not energized and the target is rotated with the circuit last turned on). As long as an angle or a rotation angle is mentioned in the present disclosure, the angle always relates to an electrical angle unless a mechanical angle is explicitly mentioned.

Thus, in the example of a pick-up single coil with 6-fold symmetry discussed herein with reference to fig. 8, the electrical angular domain corresponds to six times the mechanical angular domain. As shown in fig. 8, the HF signals or voltages amU1, amU2 are not always in phase here, but this time involve a phase shift with respect to time. The HF signals or voltages amU1, amU2 are in phase only when the LF signals U1 and U2 have the same sign. Otherwise they have a phase shift of 180 deg.. Furthermore, they are phase shifted by 90 ° with respect to the current in the target according to faraday's law of induction.

Therefore, the electrical rotation angle explained in the present disclosure corresponds to k times the actual mechanical rotation angle. Thus, only the k-fold portion of 360 ° is shown in fig. 8, i.e. 360 °/6 is 60 °. The signal is then repeated k times, so that the electrical angle of rotation is also repeated k times, i.e. here once every 60 °. Thus, for a full rotation of 360 ° in the mechanical angular domain, the electrical angular result is not unambiguous. However, there is a possibility for this to be compensated, but this is no longer the subject of the innovative concept described here.

As briefly mentioned above, according to the innovative concept described herein, the pick-up single coils 703, 704 of the pick-up coil assembly 702 are offset or rotated relative to each other by a geometric offset angle α. Here, the determination of the offset angle α depends on the number k of k-fold symmetries of the pickup single coils 703, 704 and on the variable M discussed earlier, which represents the number of pickup single coils of the pickup coil assembly and the number of signals that can be generated by means of the pickup single coils that are phase-shifted from each other. The example shown in fig. 7 is a 2-phase system with 3-fold symmetry, i.e., M-2 and k-3. Here, the offset angle α between the respective pickup monocoils 703, 704 is determined as follows:

α＝360°/k/M/2

the above formula is applicable to a pickup coil assembly having an even number of pickup single coils. Thus, in the example of fig. 7, the pick-up single coils 703, 704 will be rotated relative to each other by 360 °/k/M/2 by 360 °/3/2/2 by 30 °. Whereas in the example of fig. 8 (k 6), the pick-up single coils 703, 704 will be rotated with respect to each other by 360 °/k/M/2 by 360 °/6/2/2 by 15 °.

In a pickup coil assembly having an odd number of pickup single coils, the calculation formula of the offset angle α is as follows:

α＝360°/k/M

in addition to the embodiments of the non-directional pick-up coil assembly discussed so far, there are pick-up single coils that do not have this non-directional characteristic. The simplest example of this is a pick-up coil assembly with three pick-up single coils.

Fig. 9 shows an example of such a non-omnidirectional pick-up single coil 901, 902, 903. The pickup single coils 901, 902, 903 may also be referred to as a U coil, a V coil, and a W coil, and they may have substantially the same shape. Here it can be seen that the pick-up single coils 901, 902, 903 have a single winding. That is, unlike the non-directional pickup single coil, the non-directional pickup single coils 901, 902, 903 shown here do not have alternating windings wound in opposite directions. Therefore, the non-omnidirectional pick-up single coils 901, 902, 903 are not stray field robust by themselves.

However, the pickup single coils 901, 902, 903 may be connected with a circuit for signal processing. The circuit may calculate the difference between coil pairs, e.g. U-V, V-W, W-U, to compensate for the uniform stray field acting on all pick-up single coils 901, 902, 903.

Since the non-omnidirectional pickup single coils 901, 902, 903 do not have a counter-wound winding, each of the pickup single coils 901, 902, 903 provides a single signal, respectively. An angle sensor with an odd number M also has an odd number of non-directional pick-up single coils, i.e. there are no other non-directional pick-up single coils that would generate additional anti-phase signals.

However, in a pick-up coil assembly with an even number M, this may again behave differently. As already described above in relation to the special case of the "redundant" pick-up single coils included herein, four such non-directional pick-up single coils are also conceivable for M-2, but they are not rotated 360 °/6/3-20 ° (for k-6), but are rotated 360 °/6/4-15 °. The first pickup single coil will then have the largest signal in the target position where the third pickup single coil has the smallest signal, i.e. the signals will be shifted by 180 ° (electrical) phase, so that the third pickup single coil and the fourth pickup single coil will again be "redundant" or superfluous. Thus, this example is a pick-up coil assembly with an even number M and a "redundant" half, i.e. half of the non-omnidirectional pick-up single coils present (M/2) is sufficient, while the other half of the non-omnidirectional pick-up single coils present (M/2) will be redundant (here: M ═ 2 and four pick-up single coils, of which two of the four pick-up single coils are redundant and thus can be ignored in determining the variable M).

In the example of a pick-up coil assembly having an odd number M (here: M-3) shown in fig. 9, three pick-up single coils 901, 902, 903 generate a total of three signals, wherein the signals are phase-shifted from each other.

If the rotor is rotating at a constant rotational speed, approximately sinusoidal HF signals are generated in each of the three pick-up single coils 901, 902, 903, wherein these signals have a phase shift of 360 °/M360 °/3 ° 120 ° with respect to one another in the example described here. If the rotor rotates 360 ° (mechanical rotation angle), the envelope (i.e., the demodulated LF signal) has k periods. This means that if the arctangent value is calculated from the signal ratio, the result will change k x 360 ° to give 1080 ° (electrical angle) in total.

Fig. 10 shows a graph of the signal of such a pickup coil assembly having three pickup single coils in the time domain. The time between 0 μ s and 18 μ s is again plotted on the abscissa. Curve 910 represents the eddy current in the target generated by the excitation coil. The curve oscillates at 1MHz, is zero-mean and has a constant amplitude. In this example, the rotor is again rotated at an angular speed of 360 °/100 μ s, which corresponds to 6 x 10⁵A very high number of revolutions.

The amplitude-modulated HF signals amU, amV, amW are voltages induced in the three pickup single coils 901, 902, 903, respectively. The three pickup single coils 901, 902, 903 may have the same shape as the target, e.g. 6-fold (k ═ 6) symmetry, and the three pickup single coils 901, 902, 903 may be arranged rotated relative to each other by a geometric offset angle α. Here, the determination of the geometric deviation angle α also depends on the number k of k-fold symmetries of the system and on the number M of pickup single coils present in each pickup coil assembly or the number M of different signals generated in each pickup coil assembly that are phase-shifted from each other. In this example, the three pickup single coils 901, 902, 903(M ═ 3) each have 6-fold symmetry, i.e., k ═ 6. Thus, every two adjacent pickup single coils are offset from each other by α 360 °/k/M360 °/6/3 20 °. That is, the second pickup monocoil 902 is rotated by 20 ° with respect to the first pickup monocoil 901, and the third pickup monocoil 903 is rotated by 20 ° with respect to the second pickup monocoil 902. Therefore, the third pickup monocoil 903 is rotated by a total of 40 ° with respect to the first pickup monocoil 901.

This ensures that the respective signals U, V, W of the respective pick-up single coils 901, 902, 903 are phase-shifted by 120 ° from each other, i.e. in the electrical angle domain, wherein here again the electrical angle corresponds to k times the mechanical angle. In this connection, it should be noted that two different phase shifts are also involved here. On the one hand, for amplitude modulated HF signals amU, amV, amW (see curves 911, 912, 913 in fig. 10), the phase shift is a phase shift with respect to time. On the other hand, for the baseband signal (i.e., the demodulated LF signal U, V, W (see curves 921, 922, 923 in fig. 10)), the phase shift is a phase shift with respect to the rotation angle.

In the non-directional coils discussed with reference to fig. 9 and 10, the HF signals (i.e., voltages amU (911), amV (912), and amW (913)) are all in phase, but are 90 ° phase shifted with respect to the induced current in the target according to faraday's law of induction. Furthermore, the HF signals, i.e. the voltages amU (911), amV (912) and amW (913), are amplitude modulated, i.e. the HF signals have a carrier frequency whose amplitude varies with the position of the rotor relative to the stator.

The amplitude information contained therein can be demodulated resulting in (the positive upper part of) the envelope, i.e. the demodulated LF signals U (921), V (922) and W (923). The demodulated LF signals U (921), V (922) and W (923) have a non-zero mean value. They can therefore be obtained from non-synchronous demodulation, which is in turn simpler than synchronous demodulation, although synchronous demodulation is also effective.

All demodulated LF signals U (921), V (922) and W (923) have the same average value. This average may be eliminated by means of subtraction of the signals (e.g., U-V, V-W, W-U), so that only approximately sinusoidal variations of signal U, V, W with respect to the angle of rotation are retained.

As mentioned above, the HF signals amU, amV, amW are not stray field robust, i.e. they are non-directional. This means that ambient external magnetic flux changes can add undesired induced voltages to the signals amU, amV, amW. However, since the pick-up single coils 901, 902, 903 are substantially identical and rotated by the offset angle α relative to each other, a uniform interference field occurs in all three pick-up single coils 901, 902, 903 simultaneously and to the same extent. Thus, the uniform interference field is also cancelled by (U-V, V-W, W-U) in the subtraction of the LF signal U, V, W. Alternatively, the amplitude-modulated HF signals amU, amV, amW may be subtracted from each other (amU-amV, amV-amW, amW-amU) and the differences may then be demodulated. The differencing method of the LF signal U, V, W is shown in the graphs shown in fig. 8 and 10. In practice, the differencing method of the HF signals amU, amV, amW may be more practical.

The systems described so far have a systematic angle error which may lead to inaccuracies in the measurement when determining the angle of rotation. To explain the systematic angle error, reference may be made to fig. 11.

Purely for the sake of clarity, fig. 11 shows a single pick-up single coil 901 of the example of an induction angle sensor discussed above with reference to fig. 9, having a symmetry comprising three pick-up single coils (i.e. M3) and k 6. The respective half of the winding (blue line) may be designed in the form of conductor tracks 931 on a substrate, for example a PCB (printed circuit board), wherein these conductor tracks 931 may be designed in a first metallization layer in the substrate. The respective other half of the windings (red lines) may be designed in the form of conductor tracks 932 on a substrate, e.g. a PCB (printed circuit board), wherein these conductor tracks 932 may be designed in a different second metallization layer in the substrate. The first metallization layer may be arranged on a first main side (e.g. upper side) of the substrate, and the second metallization layer may be arranged on an opposite second main side (e.g. lower side) of the substrate.

The conductor traces 931, 932 may contact each other by means of a through-hole (via) 933 passing through the substrate. The pick-up single coil 901 may be connected by means of suitable connecting wires to a sensor circuit which processes the induction signal of the pick-up single coil 901. The connection line may for example be connected with the conductor tracks 931, 932 at a connection point 934, at which connection point 934 the conductor tracks 931, 932 are not connected to each other by means of vias.

For further explanation, reference will now be made again to fig. 9, in which three such pickup single coils 901, 902, 903 throughout the pickup coil assembly 900 are shown. Here, however, the different colors do not represent different metallization layers, but rather different pickup single coils 901, 902, 903. In addition, the connection lines 941, 942, 943 described earlier are shown for each of the pickup single coils 901, 902, 903.

As described above, in this example, the pickup single coils 901, 902, 903 are arranged offset from each other by a geometric offset angle α of 360 °/k/M of 360 °/6/3 of 20 °. The pick-up single coils 901, 902, 903 are here also realized in the form of conductor tracks designed in different metallization layers (e.g. upper and lower side). As mentioned above, since the conductor tracks of a single pick-up single coil alternate between two metallization layers by means of vias, every second conductor track shown in fig. 11 is implemented in a different metallization layer. This means that although the individual pick-up single coils 901, 902, 903 are rotated by an offset angle α of 20 ° relative to one another, the individual pick-up single coils 901, 902, 903 each have radial sections which are spaced from one another by only 10 °. This means that in a single metallization layer the radial segments are arranged at a pitch of 20 °, which is again important for the innovative concept described herein.

The rotor or the target mounted on the rotor may also have matching k-fold symmetry. Thus, in this example, the target may also have 6-fold symmetry. Fig. 12 and 13 illustrate an exemplary rotor 950 having an inductive target 951. Fig. 12 shows a practical embodiment of a copper target embedded in a plastic matrix. The target 951 may be made of stamped sheet metal, such as a sheet of copper. However, the target 951 may also be designed as a conductor trace on a PCB. FIG. 13 shows a modeled graph of the target 951. The thin lines are only schematically shown here and essentially symbolize the neutral fibers of the otherwise solid copper coils.

If all coils of the induction angle sensor are handled and mounted error-free and accurately (i.e. without significant tolerance deviations), the system (i.e. the induction angle sensor) usually still has a system angle error dphi.

The systematic angle error dphi can be calculated by means of arctangent. As an example is a pick-up coil assembly with three non-directional pick-up single coils U, V, W (M-3), where the pick-up single coil U, V, W has 6-fold symmetry (k-6). Thus, first of all the rotation angle phi' between rotor and stator in the electrical angle domain can be calculated as follows:

phi‘＝arctan₂(sqrt(3)*(U-V)；-2*W+U+V)，

wherein arctan₂(x; y) provides an angle between a vector and the positive x-axis, where the vector has an x-component x and a y-component y. The target may be fixed on the shaft. The rotational position of the shaft and the rotational position of the target relative to the pick-up single coil at the stator may be denoted phi' ═ phi k in the mechanical angular domain. Thus, the angular error dphi in the mechanical domain can be calculated according to the following formula:

dphi＝(mod(phi’-k*phi+180°；360°)-180°)/k

the rotation angle phi' in the electrical domain is also referred to herein as the electrical angle and represents k cycles of the signal during a full mechanical or actual rotation of 360 °, where k here again describes a variable of k-fold symmetry. The rotation angle phi in the mechanical domain describes the actual mechanical rotation angle, i.e. the actual rotation of 360 °, and is also referred to herein as the mechanical angle.

Fig. 14 shows a non-limiting example of such a system angle error in a pick-up coil assembly with three pick-up single coils U, V, W (M3) and 6-fold symmetry with an air gap AG of 2 mm. The air gap AG is the axial distance between the target and the pick-up coil assembly.

As can be seen in fig. 14, the systematic angle error dphi has an approximately sinusoidal shape. In this example, the average value of the angle error dphi is about-0.5 °, which is initially insignificant in the context of the inventive concept described herein. It can be seen, however, that the angle error dphi fluctuates around the mean value, i.e. in this example around ± 0.2 °. This fluctuation around the mean value of the angle error dphi is also referred to as the system error band. As the air gap becomes larger, the magnitude of the error band will become smaller. And as the air gap becomes smaller, the error band increases dramatically.

However, what can be achieved with the angle sensor described herein is: the system error band (not the average of dphi) can be kept as small as possible despite the small air gap. In this context, "as small as possible" means that the system angle error dphi is compensated such that it has only an imperceptible influence on the angle measurement. Although the average value of dphi may vary with the air gap, such as occurs when the circuit board is thick, a constant average value is irrelevant because the average value may be measured at the time of installation of the system and thus known to the system. However, the average value should not change (with temperature or air gap).

FIG. 1A illustrates one embodiment of an inductive angle sensor 100. According to the inventive concept described herein, the angle sensor 100 has a first pickup coil assembly 110 and a second pickup coil assembly. However, for the sake of clarity, the second pick-up coil assembly has not been shown here for the moment.

Fig. 1A shows a 3D model of an object 101 arranged on a rotor, not shown here. The first pickup coil assembly 110 is disposed on a stator, also not explicitly shown herein. In this non-limiting embodiment, the pickup coil assembly 110 has three non-directional pickup single coils 111, 112, 113. However, the concepts described herein are of course also applicable to a non-directional pick-up coil assembly as described hereinbefore.

The non-directional pick-up coil assembly 110 shown here provides three signals, in this case from three pick-up single coils 111, 112, 113, which are phase-shifted from each other. Therefore, an M-phase system in which M is 3, that is, a 3-phase system is referred to herein.

A stator with a pick-up coil assembly 110 and a rotor with a target 101 are arranged around a common axis of rotation R. The pick-up coil assembly 110 and the target 101 may both be arranged concentrically about the axis of rotation R. The axial distance between the target 101 and the pick-up coil assembly 110 describes an air gap, also referred to as air gap AG.

The target 101 and the pick-up coil assembly 110 have k-fold symmetry, where k is 6, i.e. in this non-limiting embodiment the target 101 and the pick-up coil assembly 110 have 6-fold symmetry. However, the innovative concepts described herein can be applied to systems with arbitrary k-fold symmetry (i.e., inductive angle sensors).

The pickup single coils 111, 112, 113 of the pickup coil assembly 110 shown here as an example with an odd number M (here M3) are rotationally offset relative to one another about the axis of rotation R by a geometric offset angle α of 360 °/k/M. For the pick-up coil assembly shown here with three pick-up single coils 111, 112, 113 and 6-fold symmetry, this means: α is 360 °/6/3 is 20 °.

Fig. 1B now shows a 3D model in a top view of a stator, which now additionally has a second pickup coil assembly 120 in addition to the first pickup coil assembly 110 described above. Purely for the sake of clarity, only two pickup coil assemblies 110, 120 and their respective pickup single coils are shown here. The two pickup coil assemblies 110, 120 may be substantially identical, i.e. they may have substantially the same geometry and the same number of pickup single coils with the same number of windings and the same shape.

Therefore, the first pickup coil assembly 110 has an odd number M of pickup single coils, i.e., the above-described three pickup single coils 111, 112, 113. Each two adjacent pickup single coils 111, 112, 113 have a geometric offset angle α of 360 °/k/M. The same applies to the second pickup coil assembly 120. The second pickup coil assembly 120 also has an odd number M of pickup single coils, i.e., three pickup single coils 121, 122, 123. Each two adjacent pickup single coils 121, 122, 123 have a geometric offset angle α of 360 °/k/M. In this example, each two adjacent pickup single coils are rotated (about the rotation axis R) by 20 ° relative to each other.

However, there are also the following facts according to the innovative concepts described herein: the respective pickup coil assemblies 110, 120 are rotated as a whole relative to each other by another geometric offset angle ρ (rho). That is, the first pickup coil assembly 110 with the corresponding pickup single coil 111, 112, 113 is rotated by an angle ρ (about the rotation axis R) with respect to the second pickup coil assembly 120 with the corresponding pickup single coil 121, 122, 123. According to one embodiment, the geometric offset angle may be, for example, ρ ≦ α (360 °/k/M for odd numbers M or 360 °/k/M/2 for even numbers M).

The geometric deviation angle ρ may vary depending on the signal evaluation type of the signal of the pickup single coil 111, 112, 113, 121, 122, 123 of the pickup coil assembly 110, 120. According to the innovative concept described herein, the combining means 130 may be designed to perform a signal combination, wherein the signal of the first pickup coil assembly 110 may be combined with the signal of the second pickup coil assembly 120 in order to determine the angle error compensated rotation angle phi' between the stator and the rotor based thereon. In some embodiments, the signal referred to herein may be, for example, a sensed output signal or a sensed signal in the so-called sense signal domain. In other embodiments, the signal mentioned here may be, for example, a rotation angle signal in the so-called angle signal domain.

The offset angles ρ of the two pickup coil assemblies 110, 120 vary with respect to each other depending on which type of signal processing is performed, i.e. in which domain. This can be taken into account by means of a correction factor n/4. In general, the geometric deviation angle ρ may be, for example, ρ ═ α × n/4, where n is an integer greater than 1, taking into account the correction factors mentioned here. Here, it still holds true for pickup coil assemblies 110, 120 with an odd number M: p 360 °/k/M × n/4, and for pickup coil assemblies 110, 120 with an even number M, apply: ρ is 360 °/k/M/2 × n/4.

According to a non-limiting embodiment that may be considered, there may be n-2. This may be the case, for example: the signal combination comprises first determining for the output signals induced in the pickup coil assemblies 110, 120 the single rotation angle signals phi1', phi2' specific to the respective pickup coil assembly 110, 120, respectively, and then combining these single rotation angle signals phi1', phi2' with each other in order to determine the angle error compensated rotation angle phi ' between the stator and the rotor based on this combination of the single rotation angle signals phi1', phi2 '. In this embodiment, the signal combination therefore includes an angle or a combination of angle signals, where a correction factor of n2 is applied. Thus, in this case, the pick-up coil assemblies 110, 120 may be offset or rotationally offset with respect to each other by an angle ρ α n/4 α 2/4 α/2.

According to another non-limiting embodiment that may be considered, there may be n-3. This may be the case, for example: the signal combination includes first combining the output signals respectively induced in the pickup coil assemblies 110, 120 with each other, and then, based on this combination of the induced output signals, finding the angle error-compensated rotation angle phi' between the stator and the rotor. Thus, in this embodiment, the signal combination comprises a combination of sensed output signals, wherein a correction factor of n-3 is applied. Thus, in this case, the pick-up coil assemblies 110, 120 may be offset or rotated relative to each other by an offset angle ρ α n/4 α 3/4.

Therefore, if the sensed output signals are combined with each other and the angle is calculated thereafter, n-3 is applied. However, if two angles are first calculated from the sensed output signal and then combined, then n-2 applies. The angle may initially also be an angle signal. Thus, the sense signal domain and the angle signal domain are defined herein. The induced signal domain comprises the voltage that can be tapped off at the pick-up single coil and possibly after a preamplifier, filter, demodulator, analog-to-digital converter. Further, signals may be added (zero point correction), the entire signals are multiplied (amplitude normalization), and a linear combination of the signals is calculated (quadrature error correction) as necessary. Then at least one angle is calculated using at least two signals (in most cases using the CORDIC algorithm for calculating the arctangent). Here, the boundary between the angle signal domain and the sense signal domain may be defined as follows: if all signals obtained directly or by combining from the pick-up single coil are multiplied by a single arbitrary number between 0.9 and 1.1, the output angle will remain unchanged if the signals are within the range of induced signals-the output angle will vary by this number if the signals are within the range of angular signals. (numbers close to 1 are used because larger numbers may cause the operator logic to overflow or may cause the circuit to operate within modulation limits).

Furthermore, in this embodiment, the two pickup coil assemblies 110, 120 are also electrically coupled to each other, thereby forming one or more pickup single coil pairs. In such a pair of pickup single coils, each of the pickup single coils of the first pickup coil assembly 110 is electrically connected to one of the pickup single coils of the second pickup coil assembly 120, respectively. In the example shown in fig. 1B here, the electrical connection is a series circuit, i.e. the respective pick-up single coils of a pick-up single coil pair are connected in series with each other. Also the HIA may be considered a parallel connection.

In the non-limiting embodiment shown in fig. 1B herein, two pickup coil assemblies 110, 120 are connected together to form a plurality of pickup coil pairs and are rotated relative to each other by an offset angle p of 15 °. The respective pick-up single coils are thus also rotated by an angle p (here 15 °) relative to each other. That is, the first pickup single coil 111 of the first pickup coil assembly 110 is rotated by 15 ° with respect to the first pickup single coil 121 of the second pickup coil assembly 120, the second pickup single coil 112 of the first pickup coil assembly 110 is rotated by 15 ° with respect to the second pickup single coil 122 of the second pickup coil assembly 120, and the third pickup single coil 113 of the first pickup coil assembly 110 is rotated by 15 ° with respect to the third pickup single coil 123 of the second pickup coil assembly 120.

The geometric offset angle p by which the entire pick-up coil assembly 110, 120 is rotated relative to each other may vary within certain limits. As far as the amounts of the geometric deviation angle ρ are mentioned here, these amounts also apply to a tolerance range of ± 10% or ± 1 °. This means that the inventive concept described herein can always provide satisfactory results even if there are deviations in the angles mentioned here within a range of ± 10% or ± 1 °.

FIG. 1C illustrates a 3D model of an induction angle sensor 100 according to the inventive concepts described herein. The target 101 and the aforementioned pick-up coil assembly 110, 120 are schematically shown rotated relative to each other by a geometric offset angle p ═ α × n/4. Here, the pick-up coil assemblies 110, 120 are also interconnected into a plurality of pick-up coil pairs. In this example, the signal combination comprises a combination of the sensed output signals, i.e. p 3/4 α applies.

Thus, the innovative concepts described herein provide for: at least one second pickup coil assembly 120 is provided which may be substantially identical to the existing first pickup coil assembly 110, but here rotated by a geometric offset angle p α n/4 with respect to the first pickup coil assembly 110. The second pickup coil assembly 120 may have a systematic angular error dphi or a corresponding angular error band, discussed previously, similar to the first pickup coil assembly 110. However, due to the rotational arrangement relative to the first pickup coil assembly 110, the curve of the systematic angular error of the second pickup coil assembly 120 will be shifted along the horizontal axis by the same offset angle ρ (see fig. 14). Therefore, the curve of the angular error band of the second pickup coil assembly 120 will be shifted with respect to the curve of the angular error band of the first pickup coil assembly 110 such that the curve of the angular error band of the second pickup coil assembly 120 has a maximum where the curve of the angular error band of the first pickup coil assembly 110 has a minimum, and vice versa.

As described above, the induction angle sensor 100 described herein has the combining device 130 (see fig. 1C). The combining means 130 may be designed to suitably combine the signal of the first pickup coil assembly 110 with the signal of the second pickup coil assembly 120 and to find the angle error compensated rotation angle phi' between the stator and the rotor based thereon. This means that the determined angle of rotation is corrected or compensated by the amount of the systematic angle error dphi or the fluctuation or mean deviation of the respective angle error band described here. The angle of rotation after the angular error compensation may be a mechanical angle of rotation phi or an electrical angle of rotation phi ', wherein the two angles of rotation may be switched with respect to each other according to phi' ═ phi × k. However, as long as the angle of rotation is mentioned here, it always refers to the electrical angle of rotation phi' unless a mechanical angle of rotation phi is directly mentioned.

As also briefly described above, when combining the signals of the two pickup coil assemblies 110, 120 to calculate the rotation angle, it is possible to distinguish: whether to combine the induced output signals (induced signal fields) of the pick-up coil assemblies 110, 120 with each other or whether to first calculate two angles from the induced output signals and then combine the two angles. Therefore, the calculation of the signal may be different, as will be explained in more detail below.

First, the mentioned signals may be amplitude modulated HF signals amU1(802), amU2(803) or amU (911), amV (912), amW (913) as discussed previously with reference to fig. 8 and 10. This means that the angle error compensated rotation angle phi' can be calculated or determined before demodulating the amplitude modulated HF signals amU1(802), amU2(803) or amU (911), amV (912), amW (913).

However, according to another embodiment, the angle error compensated rotation angle phi' may also be calculated or found after demodulating the HF signals amU1(802), amU2(803) or amU (911), amV (912), amW (913). This means that the amplitude modulated HF signals amU1(802), amU2(803) or amU (911), amV (912), amW (913) can first be demodulated in order to obtain the demodulated LF signals U1(804), U2(805) or U (921), V (922), W (923) discussed earlier with reference to fig. 8 and 10. Then, the angle error compensated rotation angle phi' may be calculated or derived based on the demodulated LF signal U1(804), U2(805), or a combination of U (921), V (922), W (923).

The mentioned combination of signals may be, for example, an average between the signal of the first pickup coil assembly 110 and the signal of the second pickup coil assembly 120.

According to a conceivable embodiment, the respective individual signals of the pick-up coil assemblies 110, 120 may be evaluated separately. For this purpose, the combining means 130 may, for example, be designed to calculate a first (electrical) rotation angle phi1' which is ascertained by means of the first pickup coil assembly 110. Furthermore, the combination device 130 may also be designed to calculate a second (electrical) rotation angle phi2' which is found by means of the second pickup coil assembly 120. Then, the combiner 130 may determine an average value MW of the two rotation angle signals phi1 'and phi2', for example, MW (phi1'+ phi 2')/2. The combiner 130 may also determine an average value MW of the two rotation angle signals phi1 'and phi2', for example, MW ═ (phi1'+ phi2' - ρ)/2, taking into account the offset angle ρ. Ignoring the offset angle p would only shift the 0 reference angle and thus would be insignificant in most cases.

In practice, an allowable angular range of 0 ° -360 ° may also be considered, where phi _ new' in the following notation corresponds to the angle of rotation after compensation of the angular error in the electrical domain:

phi_new’＝mod((phi1’+phi2’-10°)/2+180°；360°)-180°

or

phi_new’＝mod((phi1’+phi2’-10°)/2；360°)

In the above formula, the geometric offset angle ρ is given as 10 ° as a non-limiting example. This is because the signal combination includes: first, for the output signals induced in the pickup coil assemblies 110, 120, the individual rotation angle signals phi1', phi2' specific to the respective pickup coil assembly 110, 120 are determined, and then these individual rotation angle signals phi1', phi2' are combined with one another, i.e., a correction factor n of 2 can be used, where applicable (for k 6, M3 and n 2): p α n/4 or p 360 °/k/M n/4 360 °/k/M2/4 is 10 °. The first formula above maps angles from 0 ° to 360 ° into the interval between +180 ° and-180 °. The second formula maps angles from 0 ° to 360 ° into the interval between 0 ° and 360 °. Averaging the two rotation angle signals phi1 'and phi2' of the first and second pickup coil assemblies 110 and 120 eliminates the angle error (see fig. 14) and provides a very accurate result to calculate the angle error compensated rotation angle between the rotor and the stator. Averaging almost completely eliminates the angular error band.

The angle error compensated rotation angle phi _ new' given in the above equation is given in the electrical domain. Of course, the same applies here, too, to the extent that the angle error-compensated rotation angle can be converted into the mechanical region according to the following equation:

phi_new‘＝phi_new*k

in the notation given here, phi _ new 'corresponds to the angular error compensated electrical rotation angle phi' described further herein, and phi _ new corresponds to the angular error compensated mechanical rotation angle phi described further herein.

The determination of the angle of rotation phi after the angular error compensation can be performed in different ways according to the innovative concept described herein. Therefore, some conceivable embodiments for finding the angle error compensated rotation angle phi will be explained below.

According to a first embodiment of this type, the inductive angle sensor 100 may have two pickup coil assemblies 110, 120, which may be electrically separated from each other. The combining means 130 may have a first circuit connected to the first pickup coil assembly 110 and designed to calculate the above-mentioned first angle signal phi 1'. Furthermore, the combining means 130 may also have a second circuit which is connected to the second pickup coil assembly 120 and which is designed to calculate a second angle signal phi 2'. Furthermore, the combination device 130 can also have a third circuit (or microprocessor) which is designed to combine the first angle signal phi1' and the second angle signal phi2' with one another in order to determine the angle of rotation phi _ new ' or phi _ new between the stator and the rotor after the angular error compensation on the basis thereof. This can be done with a digital code or with an analog signal in the voltage domain or current domain.

According to this type of second embodiment, the concept of the first embodiment described above can be basically employed. But only a single circuit is used. The single circuit may then be connected to both the first and second pickup coil assemblies 110, 120, and may not necessarily be permanently or temporarily connected, for example by using a time division multiplexing method. Thus, for example, the control device may have a single circuit designed to determine the first angle signal phi1 'and the second angle signal phi2' by using a time-division multiplexing method. Here, in a first time interval, the single circuit may calculate at least one signal component of the first angle signal phi1 'based on the signal of the first pickup coil assembly 110 (the amplitude-modulated HF signal or the demodulated LF signal), and in a second, different time interval, the single circuit may calculate at least one signal component of the second angle signal phi2' based on the signal of the second pickup coil assembly 120 (the amplitude-modulated HF signal or the demodulated LF signal). Here, the combining means 130 may also consider: phi2 'corresponds to a rotor position later than phi1', for example due to different sampling times.

According to this type of third embodiment, as described above, the two pickup coil assemblies 110, 120 may be electrically connected in series or parallel to form a plurality of pickup single coil pairs. Here, the respective pickup single coils 111, 112, 113 of the pickup coil assemblies 110, 120; 121. 122, 123 can in particular be connected to one another. Thus, for example, the first pickup monocoil 111(U1) of the first pickup coil assembly 110 may be electrically connected with the first pickup monocoil 121(U2) of the second pickup coil assembly 120. In addition, the second pickup single coil 112(V1) of the first pickup coil assembly 110 may be electrically connected to the second pickup single coil 122(V2) of the second pickup coil assembly 120. Further, the third pickup single coil 113(W1) of the first pickup coil assembly 110 may be electrically connected to the third pickup single coil 123(W2) of the second pickup coil assembly 120. Thus, two single pick-up coil assemblies 110, 120 connected together essentially form one single pick-up coil assembly connected together. The electrical connection of the respective pickup single coils 110, 120 may be made in the form of a series connection or a parallel connection.

Thus, every two pick-up single coils interconnected to each other may form a pick-up coil pair. That is, the first pickup single coil 111(U1) of the first pickup coil assembly 110 and the first pickup single coil 121(U2) of the second pickup coil assembly 120 connected thereto (in series or in parallel) together form a first pickup coil pair U-U1 + U2. The second pick-up single coil 112(V1) of the first pick-up coil assembly 110 and the second pick-up single coil 122(V2) of the second pick-up coil assembly 120 connected thereto (in series or in parallel) together form a second pick-up coil pair V1+ V2. The third pick-up single coil 113(W1) of the first pick-up coil assembly 110 and the third pick-up single coil 123(W2) of the second pick-up coil assembly 120 connected thereto (in series or in parallel) together form a third pick-up coil pair W-W1 + W2.

Since the two pickup coil assemblies 110, 120 are rotated relative to each other by the geometric offset angle ρ (rho), the respective mutually interconnected pickup single coils U1, U2 of the pickup coil pair U, V, W; v1, V2; w1, W2 are also offset relative to each other by the offset angle ρ, respectively.

Thus, more generally, this third embodiment proposes an inductive angle sensor 100 in which the first pickup coil assembly 110 and the second pickup coil assembly 120 are electrically coupled to each other and form one or more pickup single coil pairs U, V, W. Here, in each pickup single coil pair U, V, W, one pickup single coil (e.g., 111(U1)) of the pickup single coils of the first pickup coil assembly 110 is connected in series or in parallel with a pickup single coil (e.g., 121(U2)) of the second pickup coil assembly 120, which is offset by the geometric offset angle ρ with respect thereto, respectively.

In particular, in the case of a series connection, the individual signals of the pick-up single coils, which are connected to one another in each case, add up to a common signal. That is, each pickup coil pair U, V, W provides a signal corresponding to the sum of the two individual signals of the pickup single coils respectively connected together in that pickup coil pair U, V, W. Thus, for example, the first pickup coil pair U provides a signal consisting of the signal of the first pickup single coil 111(U1) of the first pickup coil assembly 110 and the signal of the first pickup single coil 121(U2) of the second pickup coil assembly 120 interconnected with the first pickup single coil 111 (U1). The second pickup coil pair V provides a signal consisting of the signal of the second pickup monocoil 112(V1) of the first pickup coil assembly 110 and the signal of the second pickup monocoil 122(V2) of the second pickup coil assembly 120 interconnected with the second pickup monocoil 112 (V1). The third pickup coil pair W provides a signal consisting of the signal of the third pickup monocoil 113(W1) of the first pickup coil assembly 110 and the signal of the third pickup monocoil 123(W2) of the second pickup coil assembly 120 interconnected with the third pickup monocoil 113 (W1).

The combination device 130 can be designed to combine the signals of one or more pickup single-coil pairs U, V, W with one another in order to determine the angle of rotation phi' between the stator and the rotor after compensation of the angle error on the basis thereof. Here, amplitude-modulated HF signals or demodulated LF signals may be involved, i.e. the determination of the angle of rotation phi' after the angle error compensation may be carried out before or after the demodulation.

The signal of the pickup single coil U, V, W is also referred to herein as a pickup coil pair signal. The aforementioned combination of pick-up coil pair signals may for example be an averaging. For example, the combining means 130 may have a single circuit designed to average out an amplitude modulated HF signal or a demodulated LF signal. That is, as an alternative or in addition to the above-described averaging of the two angle signals phi1', phi2', the single circuit of the combining means 130 may average the amplitude-modulated HF signals for each pickup coil pair or the demodulated LF signals for each pickup coil pair and, based thereon, calculate the angle error-compensated rotation angle phi '.

Within certain limits it does not matter whether the demodulation of the signal is performed before the combination (averaging) of the signals or the combination (averaging) of the HF signals before the demodulation of the signals. If the angle is a linear function of the signal, the same result will be obtained whether the angle or the signal is averaged. However, the angle is a non-linear function of the signal (due to arctan)₂A function). Thus, averaging the signal will be different from averaging the angle in a strict mathematical sense. However, for small angular errors of less than a few degrees, all mathematical calculation rules can be linearized at a predetermined rotational position, which results in a linearized relationship. This means that one of the methods described herein (e.g. averaging the angles (phi1', phi2') may be replaced by a corresponding other method described herein (e.g. averaging the signals (LF signals or HF signals)) however, in practice it may occasionally be found that the two methods require different geometric offset angles ρ at which the two pickup coil assemblies 110, 120 are offset relative to each other.

Every two pick-up single coils 111, 112, 113 previously described; 121. 122, 123 are each interconnected in a single pick-up coil pair U, V, W substantially equivalent to the design of a single pick-up coil assembly which also has a corresponding (here three) pick-up coil pair U, V, W. Therefore, in this third embodiment, a single circuit is sufficient for averaging.

Thus, a single pickup coil assembly interconnected in this way may for example have a first pickup single coil pair U having for example a series circuit of two first pickup single coils 111, 121 of the first and second pickup coil assemblies 110, 120. Furthermore, the interconnected pickup coil assembly may also have a second pickup single coil pair V, for example having a series circuit of two second pickup single coils 112, 122 of the first and second pickup coil assemblies 110, 120. Furthermore, the interconnected pickup coil assembly may also have a third pickup single coil pair W, for example having a series circuit of two third pickup single coils 113, 123 of the first and second pickup coil assemblies 110, 120. Thus, in an interconnected pickup coil assembly, for example, the interconnected pickup single coil U, V, W is each wound twice (i.e. in the same direction, e.g. in a clockwise direction) about the axis of rotation R, while the respective pickup single coil 111, 112, 113 of each pickup coil pair U, V, W; 121. 122, 123 each surround the axis of rotation R only once. This third embodiment has the advantage that connecting the two pick-up coil assemblies 110, 120 together to form a single connected pick-up coil assembly achieves a larger induced signal swing and smaller error due to the fact that the pick-up single coils 111, 112, 113; 121. 122, 123 and the combining means 130 are caused by unavoidable asymmetries.

According to a conceivable fourth embodiment, as briefly described above, the pickup single coils 111, 112, 113; 121. 122, 123 may be connected together in parallel, respectively. That is, the first pickup single coil 111 of the first pickup coil assembly 110 may be connected in parallel with the first pickup single coil 121 of the second pickup coil assembly 120. The second pickup single coil 112 of the first pickup coil assembly 110 may be connected in parallel with the second pickup single coil 122 of the second pickup coil assembly 120. And the third pickup single coil 113 of the first pickup coil assembly 110 may be connected in parallel with the third pickup single coil 123 of the second pickup coil assembly 120.

According to a conceivable fifth embodiment, the pickup single coils 111, 112, 113; 121. 122, 123 may be used separately, i.e. they are not electrically connected in series or parallel to a plurality of pick-up single coil pairs. Therefore, the pickup monocoil is not connected together to constitute a pickup monocoil pair. Thus, for example, there would be two pickup coil assemblies 110, 120 arranged offset with respect to one another, which two pickup coil assemblies 110, 120 have three pickup single coils 111, 112, 113, 121, 122, 123, respectively, so that there are a total of six pickup single coils, wherein each two pickup single coils can be electrically combined in the chip, so that three coil signals are then obtained again (M ═ 3). Pickup single coils 111, 112, 113 that are not interconnected with each other; 121. 122, 123 may be connected to respective circuits. That is, the first pickup single coil 111 of the first pickup coil assembly 110 may be connected with a first circuit in order to process an output signal of the first pickup single coil 111 of the first pickup coil assembly 110 (e.g., U1). The first pickup monocoil 121 of the second pickup coil assembly 120 may be connected to a different second circuit in order to process the output signal of the first pickup monocoil 121 of the second pickup coil assembly 120 (e.g., U2). The output signals of the two circuits can then be combined with one another in the electronic domain, for example by adding or averaging the respective output voltages or output currents (optionally after a preamplifier stage and/or after a demodulation stage). The circuit may for example have a preamplifier or transconductance stage, for example in the form of an OTA (transconductance operational amplifier) which converts an input voltage into an output current. Also in this fifth embodiment, the combination (averaging) of the signals can be done in the HF domain or in the LF domain, i.e. before or after demodulation.

That is, in this embodiment, the angle sensor 100 has a pair of coils 111, 112, 113; 121. 122, 123 (here 6) corresponding to a certain number of circuits. Thus, in this non-limiting example, for six pickup monocoils 111, 112, 113; 121. 122, 123, there will be six circuits. Alternatively, the respective output signals (U1, U2; V1, V2; W1, W2) of the pickup monocoil may be combined with each other after amplification and/or demodulation, i.e., signal U1 is combined with signal U2, signal V1 is combined with signal V2, and signal W1 is combined with signal W2.

Therefore, the combining means 130 is designed to combine the output signal U1 of the first single-pick-up coil 111 of the first pick-up coil assembly 110 with the output signal U2 of the first single-pick-up coil 121 of the second pick-up coil assembly 110, and to combine the output signal V1 of the second single-pick-up coil 112 of the first pick-up coil assembly 110 with the output signal V2 of the second single-pick-up coil 122 of the second pick-up coil assembly 120, and to combine the output signal W1 of the third single-pick-up coil 113 of the first pick-up coil assembly 110 with the output signal W2 of the third single-pick-up coil 123 of the second pick-up coil assembly 120. Thus, as a result, three combined coil signals U, V, W are obtained, which can be used to determine the angle error-compensated rotation angle phi' between the stator and the rotor.

More generally, in this fifth embodiment, the combining means 130 may have a first circuit and a second circuit. A first circuit may be connected to the pickup monocoil 111 of the first pickup coil assembly 110 and the first circuit may be designed to process the signal (HF signal or LF signal) of this pickup monocoil 111 and generate a first monocoil output signal (e.g., a first output current signal of the OTA). A second circuit may be connected to the pickup monocoil 121 of the second pickup coil assembly 120 and the second circuit may be designed to process the signal (HF signal or LF signal) of this pickup monocoil 121 and generate a second monocoil output signal (e.g. the first output current signal of the OTA). The combining means 130 may be designed to combine (e.g. average) the respective first and second single-coil output signals (HF signal or LF signal) of the pickup coil assemblies 110, 120 with each other, respectively, in order to determine the angle error compensated rotation angle phi' between the stator and the rotor based thereon.

The third embodiment described above is advantageous because it requires minimal electronic resources, e.g. only one chip. In principle, all circuits can always be integrated on one chip. Nevertheless, the system according to the fifth embodiment described above requires significantly less circuitry on the chip (e.g. fewer amplifiers, fewer pads, fewer protection lines per pad, e.g. ESD protection, etc.) than the previous embodiments. However, for redundancy reasons, it may be desirable to distribute the circuitry over both chips, e.g. if one chip fails, the second chip may continue to operate.

The first embodiment described above is advantageous because it is very reliable because it implicitly has redundancy. This embodiment has two completely separate pick-up coil assemblies 110, 120, each connected to its own circuit. The combination (e.g. averaging) of the two rotation angles phi1', phi2' can be performed in a subsequent stage (e.g. a microprocessor). Furthermore, the processing circuitry (e.g. a microprocessor) may also compare the two angles phi1 'and phi2' with each other. If the deviation is significantly greater than the desired angular error dphi, the combining means 130 may issue an alarm, since one of the pick-up coil assemblies 110, 120 or one of the circuits may be faulty at this time.

The second embodiment described above is a hybrid system of the first and third embodiments. The second embodiment has only one circuit, although it also has two pick-up coil assemblies 110, 120. Thus, this second embodiment is redundant in terms of the pick-up coil assemblies 110, 120, but not in terms of the sensor system or circuitry. This second embodiment is particularly suitable for low rotational speeds, since the two pick-up coil assemblies 110, 120 are scanned at different times.

It is contemplated that the stator has a single substrate (e.g., PCB) that can be used in all embodiments described herein simultaneously. This provides a very versatile stator for the induction angle sensor 100. There may be enough space on the PCB to place both pickup coil assemblies 110, 120 on the PCB without any problems. As already described herein by way of example, for a pickup coil assembly having three pickup single coils (M-3) and six-fold symmetry (k-6), the pickup single coils 111, 112, 113 of each pickup coil assembly 110, 120; 121. 122, 123 are offset relative to one another by an offset angle α of 360 °/k/M of 20 °. Thus, the respective pickup single coils 111, 112, 113 of the respective pickup coil assemblies 110, 120; 121. the radial segments 122, 123 are each spaced 20 ° apart relative to one another in a single metallization layer. Thus, for example, the entire first pickup coil assembly 110 may be deflected relative to the second pickup coil assembly 120 such that the radial sections of the pickup single coils 111, 112, 113 of the first pickup coil assembly 110 are respectively arranged in the middle between the radial sections of the pickup single coils 121, 122, 123 of the second pickup coil assembly 120, i.e. the geometric offset angle between the two pickup coil assemblies 110, 120 is in this case ρ ═ α n/4 ═ 360 °/k/M/n/4, where n ═ 2, i.e. ρ ═ α/2 ═ 10 °. The factor n2 applies in particular to the following cases: first from the pick-up single coil 111, 112, 113; 121. 122, 123, two angles are calculated from the sensed output signals and then the two angles are combined.

After the pickup single coils 111, 112, 113; 121. 122, 123 are combined with each other before the angle is calculated, a factor n of 3 may be used. Thus, in this example (k-6; M-3), the offset angle would be ρ -15 °.

It is generally entirely feasible that the two pickup coil assemblies 110, 120 are rotated by a geometric offset angle p ═ α × n/4, where n is an Integer greater than 1 (Integer). That is, the variable n may also have other values than n-2 or n-3, which are only exemplary described here.

For example, the variable n may have a value between n-1 and n-10, or between n-1 and n-5, or between n-1 and n-3. For example, the variable n may have a value such that an angle ρ (rho) is produced at which the radial sections of the pickup single coils 111, 112, 113 of the first pickup coil assembly 110 are arranged between the radial sections of the pickup single coils 121, 122, 123 of the second pickup coil assembly 120, respectively.

The non-limiting embodiments described so far basically relate to pickup coil assemblies 110, 120 with an odd number of pickup single coils 111, 112, 113, 121, 122, 123 (M-3) and 6-fold symmetry (k-6) and a non-omnidirectional pickup single coil, wherein the pickup coil assemblies 110, 120 may be rotated p-10 ° relative to each other, for example. In order to find the angle error compensated rotation angle phi, the respective angle signals phi1', phi2' of the respective pickup coil assemblies 110, 120 may be used, wherein for example the two angle signals phi1', phi2' may be averaged.

However, the concepts described herein and all that is described herein with respect to a non-directional pick-up single coil may also be used for a non-directional pick-up coil assembly having two pick-up single coils (COS coil, SIN coil) each.

Fig. 2A shows a schematic diagram of a single cosine coil or pickup single coil 111. Fig. 2B shows the omnidirectional pickup coil assembly 110, the omnidirectional pickup coil assembly 110 having a first pickup single coil (COS coil) 111 and a second pickup single coil (SIN coil) 112 rotated by an offset angle α with respect thereto.

Fig. 2A and 2B show an example of a pickup coil assembly having two pickup single coils 111, 112(M ═ 2), which two pickup single coils 111, 112 belong to the target with triple symmetry (k ═ 3), i.e. the illustrated pickup single coils 111, 112 each have 3-fold symmetry, i.e. k ═ 3. As already described herein, each two adjacent windings of the pick-up single coil 111, 112 have respectively opposite winding directions (see arrows shown) in order to provide a stray field robust (i.e. non-directional) coil system. Thus, the pickup monocoils 111, 112 shown here are non-directional pickup monocoils. The signals of the two pickup monocoils 111, 112 are here phase-shifted by 90 ° from each other.

In FIG. 2A, radial segment 111_R1(blue) is designed in a first metallization plane or metallization layer, and radial segments 111_R2The (orange) is designed in a different second metallization plane or metallization layer. The two metallization layers are formed byFacilitating through-hole (via) interconnection. The pickup single coil 111 has six windings arranged in a circular arrangement around the rotation axis R. Here, the winding direction of every second winding changes, i.e. every two adjacent windings have opposite winding directions (see arrows). Thus, the arrow points clockwise in the first winding and counterclockwise in the adjacent second winding, then points again clockwise in the next adjacent third winding, points again counterclockwise in the next adjacent fourth winding, and so on.

Fig. 2A shows a complete non-directional pickup coil assembly 110 having the aforementioned first pickup single coil 111 (e.g., COS coil) and an additional second pickup single coil 112 (e.g., SIN coil). The first pickup monocoil 111 is shown in solid lines and the second pickup monocoil 112 is shown in dashed lines. Here, the windings of the respective pick-up single coils 111, 112 also alternate between the two metallization layers as previously described with reference to fig. 2A.

The first pickup monocoil 111(COS coil) may be the same as the second pickup monocoil 112(SIN coil). The two pickup single coils 111, 112 may be rotated relative to each other about the rotation axis R by a geometric offset angle α of 360 °/k/M/2 (this formula applies to all pickup coil assemblies having an even number of pickup single coils). Thus, in this example (M-2, k-3), the two pick-up single coils 111, 112 may be rotated, for example, by 360 °/3/2/2-30 ° relative to each other.

A second non-directional pick-up coil assembly 120 may now be provided in accordance with the innovative concepts described herein. For clarity, the second non-directional pickup coil assembly 120 is not explicitly shown here. The second omnidirectional pickup coil assembly 120 may be substantially the same as the pickup coil assembly 110 previously described with reference to fig. 2A. That is, the second pickup coil assembly 120 may also have the first unidirectional pickup single coil 121 and the second unidirectional pickup single coil 122 rotated by an offset angle α of 360 °/k/M/2 with respect thereto. These pick-up single coils 121, 122 may also be referred to as cosine coils or sine coils due to their signal shape.

For better distinction, the pickup single coils 111, 112 of the first pickup coil assembly 110 are also referred to as COS1 coil and SIN1 coil, while the pickup single coils 121, 122 of the additional second pickup coil assembly 120 are also referred to as COS2 coil and SIN2 coil.

The two pickup coil assemblies 110, 120 may be rotated relative to each other by a geometric offset angle p (rho). The offset angle ρ may be, for example, ρ ═ α × n/4 or ρ ═ 360 °/k/M/2 × n/4, wherein in this example (k ═ 3; M ═ 2), if the signal combination comprises: first, the single rotation angle signals phi1', phi2' specific to the respective pickup coil assembly 110, 120 are determined for the output signals induced in the pickup coil assembly 110, 120, and then these single rotation angle signals phi1', phi2' are combined with each other, so that n may be 2. However, if the signal combination includes: if the output signals respectively sensed in the pickup coil assemblies 110, 120 are first combined with each other, and then the angle error-compensated rotation angle phi' between the stator and the rotor is determined based on this combination of the sensed output signals, then n may be equal to 3. In the former case (i.e. combining the angle signals and n is 2), the offset angle between the two pickup coil assemblies 110, 120 is ρ is 15 °, i.e. the first pickup coil assembly 110 will be rotated 15 ° relative to the second pickup coil assembly 120. In the latter case (i.e. combining the sensed output signals and n being 3), the offset angle is, for example, p being 22.5 °, i.e. the first pickup coil assembly 110 will be rotated 22.5 ° relative to the second pickup coil assembly 120.

In such an omnidirectional pickup coil system, the combining means 130 may also be designed to combine (e.g., average) the signal of the first pickup coil assembly 110 and the signal of the second pickup coil assembly 120 with each other so as to find the angle error-compensated rotation angle phi based thereon. The signal may be the angle signal phi1', phi2' or an amplitude modulated HF signal as described above, or a demodulated LF signal.

In one of the five different embodiments described above, a non-directional pick-up coil system can also be designed. The pickup single coils 111, 112; 121. 122 may in particular be connected together to form a pick-up coil pair COS, SIN, for example in series or in parallel. For example, the SIN1 coil and the SIN2 coil may be connected together to form a first pickup coil pair SIN, and the COS1 coil and the COS2 coil may be connected together to form a second pickup coil pair COS.

To demonstrate the innovative concepts described herein, a mathematical model was developed, which will be explained in more detail below with reference to fig. 3A-6C. It is intended to illustrate how the geometric offset angle p (rho) of the two (identical) pickup coil assemblies 110, 120 can be determined in order to ensure the best possible accuracy in determining the rotation angle phi between the rotor and the stator, i.e. so as to compensate the angular error band as best as possible (see fig. 14).

For the sake of completeness, it should be mentioned in advance that the offset angle ρ (rho) can be derived from the periodicity of the systematic angle error curve of a conventional angle sensor system (here rho is, for example, the angular spacing between a maximum and a minimum). Alternatively, the angle p (rho) may be found by calculating or measuring the resulting systematic angle error (similar to the diagram in fig. 3A).

For this purpose, in the following, it will be assumed that the induction angle sensor 100 has three pickup single coils 111, 112, 113, respectively; 121. 122, 123 or U1, V1, W1; two non-directional pick-up coil assemblies 110, 120 of U2, V2, W2 (i.e., M ═ 3) and corresponding targets, wherein the pick-up coil assemblies 110, 120 and targets each have 6-fold symmetry (i.e., k ═ 6). The pickup single coils U1, V1, W1 of the first pickup coil assembly 110 may be respectively connected in series or parallel with the corresponding pickup single coils U2, V2, W2 of the second pickup coil assembly 120 to each other as a pickup coil pair U, V, W in the manner described above (see the previously discussed third embodiment). Therefore, signals of the pickup single coils respectively connected together to constitute the pickup coil pair add to a common coil pair signal. Alternatively, the signals of the pick-up single coils may be electrically combined (see the fifth embodiment discussed above).

Fig. 1A has shown such a coil system with M-3, however, for clarity, only a single pick-up coil assembly 110 is shown. The pickup single coils 111(U1), 112(V1), 113(W1) shown are only schematically shown here as closed windings. However, in practice the pick-up single coil 111, 112, 113 is open at some point in order to provide an electrical terminal at which a signal can be tapped. The exciter coil is not shown here. The excitation coil would be arranged in a circular fashion around the pickup coil assembly 110 and in the same metallization plane as the pickup coil assembly 110.

According to the innovative concepts described herein, a substantially identical second pick-up coil assembly 120 may now be provided (see fig. 1B, 1C). The second pickup coil assembly 120 may likewise have three pickup single coils 121(U2), 122(V2), 123(W2) (M ═ 3), and is arranged to be rotated about the rotation axis R by the geometric offset angle ρ (rho) with respect to the first pickup coil assembly 110. In this example (k 6; M3; n 3) the offset angle p may be calculated as: ρ ═ α × n/4 ═ 360 °/k/M × n/4 ═ 360 °/6/3 ═ 3/4 ═ 15 °. In the model calculations discussed herein, the offset angle ρ varies between 2 ° and 18 °.

At pickup single coil U1, V1, W1; the signals induced in U2, V2, W2 are extracted and combined, for example by applying an averaging. For the model calculation, the amplitude-modulated HF signals are first (mathematically) demodulated and the LF signals are then added (U1+ U2; V1+ V2; W1+ W2). Then, the angle signals phi1', phi2' and the angle error band are calculated for all rotational positions between the rotor and the stator. Finally, the maximum angular error over one full rotation is acquired and plotted against the offset angle (angular displacement) of the two pickup coil assemblies 110, 120. Corresponding graphs are shown in fig. 3A and 3B.

Fig. 3A shows three different curves at three different air gaps. Curve 301 is calculated for an air gap of 1mm, curve 302 is calculated for an air gap of 2mm, and curve 303 is calculated for an air gap of 3 mm. It can be seen that the maximum angle error AE increases sharply with small air gaps. It can also be seen that the maximum angle error AE becomes very small, i.e. independent of the air gap, at a geometric offset angle ρ (rho) of about 15 °. The reason for this is that the angle error can be spectrally resolved and the innovative concept described herein eliminates the third harmonic. It is unexpected here that the higher harmonics are clearly much smaller, so that the residual error drops off drastically.

The optimum geometric offset angle p (rho) between the first pickup coil assembly 110 and the (same) second pickup coil assembly 120 can be found to obtain as small a systematic angular error as possible. Furthermore, the optimal geometric offset angle ρ (rho) is independent of the rotor or target, which is a great advantage of the present concept. That is, the innovative concepts described herein are applicable to almost all types and forms of rotors or targets, such as rotors or targets having 6-fold symmetry (k-6).

Fig. 3B shows the result of angular error compensation according to the inventive concept described herein. It can be seen that with an air gap of 3mm, the systematic angular error band decreases from the initial ± 0.2 ° (see fig. 14) to ± 0.02 °. This corresponds to a 10 times reduction in the angle error.

It should furthermore be mentioned that in the graph shown in fig. 3B the pick-up coil assemblies 110, 120 are modeled as being offset with respect to each other by p 16 °, i.e. the modeled offset angle p deviates from the calculated (optimum) offset angle p by 15 ° (see above). It can be seen that despite such deviations in the offset angle ρ, the angle sensor 100 provides very good and reproducible results.

In this example, the original pick-up coil assembly has a periodicity of 360 °/6 ═ 60 °, i.e. the size of the "teeth" of the pick-up coil is 30 °, and the size of the "gaps" of the pick-up coil is likewise 30 °. The optimization results shown here mean that the (same) second pick-up coil assembly must be rotated by half a tooth (30 °/2 — 15 °) in order to compensate the system angle error as optimally as possible.

If this finding is now applied, for example, to the pickup single coil 901(U1) shown in fig. 11, this means that a (identical) second pickup single coil 121(U2) of a (identical) second pickup coil assembly 120 may be added, which is rotated by 15 ° with respect to the pickup single coil 901(U1) shown. Fig. 4 shows a schematic diagram of this arrangement. It can also be seen that the two pick-up single coils 901(U1), 121(U2) are connected in series (see the third embodiment discussed above). Thus, essentially a single pick-up single coil U (where U-U1 + U2) is combined or connected together.

As can be seen in the upper part of fig. 4, the geometry of the coil is slightly changed here so that the two pickup single coils 901(U1), 121(U2) can be interconnected. The effect of the interconnection of the pickup single coils 901(U1), 121(U2) will be briefly described below with reference to fig. 5.

Fig. 5 shows a schematic diagram of two pickup single coils 901(U1), 121(U2) in an expanded view of their windings. The unwound winding may be plotted on a (psi, r) plane, with azimuthal position plotted on the abscissa and radial position plotted on the ordinate. The first pickup single coil 901(U1) is shown in the upper part of the figure. The second pick-up single coil 121(U2) is shown in the middle. It can be seen that the respective windings of the respective pickup monocoil 901(U1), 121(U2) are offset by 30 ° from each other, respectively, and the two pickup monocoils 901(U1), 121(U2) are offset by 15 ° from each other.

Each of the two pickup single coils 901(U1), 121(U2) collects magnetic flux at a corresponding function (6 teeth, 6 gaps) (shown in light gray). As described above, the second pickup monocoil 121(U2) is offset by 15 ° in the azimuth direction (psi direction) with respect to the first pickup monocoil 901 (U1). If the magnetic flux of the second pickup monocoil 121(U2) is added to the magnetic flux of the first pickup monocoil 901(U1), an overlapping area where the magnetic fluxes are doubled is obtained. This is shown in the lower illustration of fig. 5. The overlapping area (dark grey) is marked with "x 2" to indicate double the magnetic flux. As can be seen in the illustration shown in fig. 5, the combination of the two pickup monocoils 901(U1), 121(U2) makes the weight for collecting the magnetic flux appear to be approximately sinusoidal in shape.

Fig. 6A, 6B, and 6C show such sinusoidal-shaped curves. Fig. 6A shows the magnetic flux density of the first pickup monocoil 901(U1), fig. 6B shows the magnetic flux density of the second pickup monocoil 121(U2), and fig. 6C shows the result of overlapping the two pickup monocoils 901(U1), 121 (U2).

The above-described embodiments are merely illustrative of the principles of the innovative concepts described herein. It is to be understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the concepts described herein be limited only by the scope of the appended claims and not by the specific details presented herein with reference to the description and illustration of the embodiments.

Although some aspects are described in connection with an apparatus, it is to be understood that these aspects also represent a description of the respective method, so that a module or component of the apparatus can also be understood as a respective method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding module or detail or feature of a corresponding device.