Position sensor with primary and noyes tracks

Abstract

A sensing system and method for sensing position includes a first magnetic rail for generating a magnetic field and a second sensor for sensing the magnetic field. The first magnetic rail includes a first number of multipoles and is securely fixed to the second magnetic rail for generating the magnetic field, thereby forming a magnetic structure. At least two sensors are included. The first sensor is positioned closer to the first magnetic rail than closer to the second magnetic rail. The second sensor is positioned closer to the second magnetic rail. The distance between the first sensor and the second magnetic rail is greater than the distance between the second sensor and the second magnetic rail. The magnetic flux density generated by the first and second magnetic rails follows a ratio of 2 or higher.

Description

Technical Field

[0001] This invention relates to the field of position sensing. More specifically, this invention relates to a position sensing system for determining the relative position of a magnetic structure with respect to a magnetic field sensor. Background Technology

[0002] Position sensing systems are typically included in devices that require the detection of the position of some of their components. For example, many engines include angular position sensing systems to detect the relative position of the rotor with respect to the stator in order to ensure proper power supply to the engine coils.

[0003] These typically consist of a magnetic field sensor and a magnetic component. The relative motion of one component with respect to the other is detected by the sensor, which provides a signal. The accuracy, resolution, and other characteristics of the measured signal depend on several factors, such as the type of magnet. Conventional rotary encoders with simple dipole magnets and Hall effect sensors are limited to approximately 0.02 degrees in angular resolution and approximately 0.3 degrees in angular accuracy that varies with temperature, also depending on the signal-to-noise ratio.

[0004] Multipole magnets improve the resolution and accuracy of relative positioning. However, multipole magnets are divided into sectors, and the position of the angular sector itself cannot be identified using a magnetic sensor alone. This means that information relative to the absolute angular position is lost.

[0005] To address this, existing magnetic structures include two multipole tracks, one of which has one fewer pole pair than the other. Therefore, the entire 360° range can be reconstructed by combining signals from the two tracks acquired by a pair of sensors, typically integrated into a single chip. The track with the most poles is the "master track."

[0006] The difference between the signals from the two tracks is used to distinguish sectors, while the signal from the main track is used to measure angles. However, these types of systems exhibit high crosstalk between fields. The tracks can be physically separated to reduce crosstalk, but this requires two separate chips; alternatively, integrating the sensors requires greater separation and therefore a larger sensor chip area, thus increasing cost. Summary of the Invention

[0007] The object of embodiments of the present invention is to provide a sensing system and a position sensor including such a system, as well as a method for sensing position. The present invention allows for accurate detection of the position of a magnetic structure relative to a magnetic sensor without losing information about the absolute position. It also allows for providing a compact sensing system in which sensors can be integrated. In a first aspect, the present invention provides a sensing system for sensing position, including a first magnetic rail for generating a magnetic field and a second magnetic rail for generating a magnetic field, the first magnetic rail including a first number of multipoles. The first and second magnetic rails are firmly fixed to each other to form a magnetic structure. At least a first sensor and a second sensor are included for sensing the magnetic field at different locations. The first sensor is positioned close to the first magnetic rail, closer to the first magnetic rail than close to the second magnetic rail. The second sensor is positioned close to the second magnetic rail. The distance between the first sensor and the second magnetic rail is greater than the distance between the second sensor and the second magnetic rail. The magnetic flux density generated by the first and second magnetic rails follows a ratio of 2 or higher. An advantage of embodiments of the present invention is that the signal sensed by the first sensor is affected by a negligible contribution from crosstalk from the weaker second magnetic rail, thus eliminating the need for crosstalk compensation, while providing a compact device and a highly integrable sensor. In some embodiments of the invention, the projection of the first sensor in a direction perpendicular to the track (in the direction of the distance between the sensor and the magnetic structure) overlaps with the first track. In some embodiments, the projection of the second sensor in the direction of the distance between the second sensor and the magnetic structure does not overlap with the first track. For example, the projection of the second sensor overlaps with the gap of non-magnetic material disposed between the first and second tracks. For example, the projection of the second sensor overlaps with the second track. The invention is not limited thereto, and the second sensor may be positioned such that its projection also overlaps with the first track.

[0008] In some embodiments of the invention, the track is a concentric track rotatable about a common axis of rotation.

[0009] An advantage of embodiments of the present invention is that it can provide an angular position sensing system.

[0010] In a particular embodiment, the tracks are coplanar. The second track is enclosed by the first track. The first track has a first predetermined width, and the second track has a second predetermined width. The first predetermined width is at least twice the size of the second predetermined width.

[0011] An advantage of embodiments of the present invention is that it can provide a sensing system with a flat profile.

[0012] In some embodiments of the invention, the first track and the second track are stacked rings having the same outer radius. The width of the first track defined in the axial direction is at least twice the width of the second track.

[0013] An advantage of embodiments of the present invention is the ease of providing a ring-shaped multipole. A further advantage is that the sensor can be located on one side, which may be desirable under certain spatial constraints.

[0014] In some embodiments of the invention, the first orbital is a multipole having at least eight dipoles, wherein the second orbital includes a non-zero number of dipoles, which is different from the number of dipoles in the first orbital.

[0015] An advantage of embodiments of the present invention is that the sensing system can be made more compact compared to other solutions with more poles.

[0016] In some embodiments of the present invention, the first sensor and the second sensor are adapted to sense different field components, typically tangential field components and axial field components.

[0017] The advantage of embodiments of the present invention is that the position relative to the second orbit can be obtained by a linear combination of the axial field component and the tangential field component; the axial component is generally less sensitive to crosstalk.

[0018] In some embodiments of the present invention, the first sensor and the second sensor are integrated into a single semiconductor chip.

[0019] The advantage of embodiments of the present invention is that manufacturing costs can be reduced without sacrificing compactness or accuracy.

[0020] In embodiments of the invention, the system further includes signal processing means for processing signals from the sensor. The system further includes a signal output for providing the absolute position of the first track relative to the sensor.

[0021] An advantage of embodiments of the present invention is that the sensing system can be used as a position sensor.

[0022] In a particular embodiment, the processing device is adapted to calculate the initial position based on measurements from the second sensor when the sensing system is started.

[0023] An advantage of embodiments of the present invention is that the sensing system can provide sector identification during power-on, thus allowing for simple adaptation by taking into account measurements from the first sensor. A further advantage is the reduction in computational load, thereby increasing sensing speed.

[0024] In a particular embodiment, the processing device is adapted to acquire the position using measurement signals from the first sensor and the second sensor, and to calibrate the position.

[0025] The advantage of embodiments of the present invention is that the simple lookup table can be used to compensate for, for example, mechanical misalignment or defects in tracks.

[0026] In a second aspect, the present invention provides a method for sensing position using a sensing system as described in any of the preceding claims, the method further comprising retrieving measurements from a first sensor and a second sensor, and calculating the position of a magnetic structure relative to the first sensor.

[0027] An advantage of embodiments of the present invention is that location can be obtained without crosstalk compensation.

[0028] In some embodiments of the invention, the method further includes subsequently calibrating the results to compensate for mechanical misalignment.

[0029] An advantage of embodiments of the present invention is that a simple lookup table can be used.

[0030] In some embodiments of the invention, the method further includes detecting the position of the first track by using measurements of the dipoles of a magnetic structure (the sensor being on the magnetic structure) by a first sensor and a second sensor, while ignoring measurements of the second sensor by the second sensor to detect the absolute position of the first sensor relative to the magnetic structure.

[0031] An advantage of embodiments of the present invention is that the initial measurement can be updated using the measurement of the absolute position.

[0032] In some embodiments of the invention, the detection of the dipole's position and absolute position is performed upon sensor activation, for example as a first step. The method further includes ignoring the signal from the second sensor in subsequent measurements after the initial position of the first track has been detected, by using measurements from a first sensor for retrieving the dipole of a magnetic structure (the sensor being located on the magnetic structure). An advantage of this method is that it can provide faster measurements.

[0033] In some embodiments of the invention, the position of the first track is detected by performing a linear combination of measurements from the first and second sensors, using measurements of the dipoles of a magnetic structure (on which the sensors are located) from a first sensor and a second sensor, and measurements of the absolute position of the first sensor relative to the magnetic structure.

[0034] In some embodiments of the invention, calculating the position of the magnetic structure relative to the first sensor includes retrieving a linear combination of the axial and tangential components of the magnetic fields generated by the two orbits.

[0035] A further advantage is that the method can provide the position of the second orbit without complex calculations, which allows the reconstruction of the system's absolute position, such as the angular position within a 360° period.

[0036] Specific and preferred aspects of the invention are set forth in the appended independent and dependent claims. Features from the dependent claims may be appropriately combined with features of the independent claims and other dependent claims, and not merely as expressly set forth in the claims.

[0037] These and other aspects of the invention will be apparent from the embodiments described herein, and are illustrated with reference to these embodiments. Attached Figure Description

[0038] Figure 1 The diagram shows a prior art sensor and a rotatable axis that serves as the target to be measured.

[0039] Figure 2 Three magnetic structures or encoders with multiple poles are shown; the first two are angle encoders, while the third is linear.

[0040] Figures 3 to 10 Different sensor devices are shown, including multiple magnetic sensors with different distributions and suitable for measuring the orthogonal components of magnetic fields.

[0041] Figure 11 A sensing system comprising a sensor device and a magnetic structure for angular position sensing according to an embodiment of the present invention is shown.

[0042] Figure 12 It shows Figure 11 A top view of the system.

[0043] Figure 13 An alternative sensing system comprising a sensor device and a magnetic structure for angular position sensing according to an embodiment of the present invention is shown.

[0044] Figure 14 An alternative sensing system comprising a sensor device and a magnetic structure for linear position sensing according to an embodiment of the present invention is shown.

[0045] Figure 15 It shows how to use such Figure 1 or Figure 2 The illustration shows a prior art position sensing system that uses signal processing to acquire the absolute position of a target.

[0046] Figure 16 An illustrative method for obtaining the absolute position of a target using a sensing system according to an embodiment of the present invention is shown.

[0047] These accompanying drawings are illustrative and not restrictive. In the drawings, some elements may be enlarged and not drawn to scale for illustrative purposes.

[0048] Any reference numerals in the claims should not be construed as limiting the scope.

[0049] In different accompanying drawings, the same reference numerals refer to the same or similar elements. Detailed Implementation

[0050] The invention will be described with reference to specific embodiments and particular drawings, but the invention is not limited thereto but is defined only by the claims. Scale and relative scale do not correspond to actual reductions in the practice of the invention.

[0051] Furthermore, the terms first, second, etc., used in the specification and claims are used to distinguish between similar elements and are not necessarily used to describe a sequence in time, space, rank, or any other way. It should be understood that the terms thus used are interchangeable where appropriate, and the embodiments of the invention described herein can be operated in a different order than those described or illustrated herein.

[0052] Furthermore, the terms "top," "below," etc., used in the specification and claims are for descriptive purposes and are not necessarily used to describe relative positions. It should be understood that such terms are interchangeable where appropriate, and that embodiments of the invention described herein can operate in orientations different from those described or illustrated herein.

[0053] It should be noted that the term "comprising" as used in the claims should not be construed as limiting the means listed thereafter; it does not exclude other elements or steps. Therefore, the term should be interpreted as specifying the presence of the stated features, integers, steps, or components as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the term "comprising" covers both the case where only the stated features are present and the case where these features are present along with one or more other features. Therefore, the scope of the statement "device comprising means A and B" should not be construed as limiting it to a device consisting only of components A and B. This means that, for the purposes of this invention, the relevant components in the device are only A and B.

[0054] Throughout this specification, the reference to "an embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Therefore, the phrase "in one embodiment" or "in an embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, although they may. Furthermore, in one or more embodiments, as will be apparent to those skilled in the art from this disclosure, particular features, structures, or characteristics can be combined in any suitable manner.

[0055] Similarly, it should be understood that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, drawing, or description for the purpose of simplification and aiding in the understanding of one or more of the various inventive aspects. However, this method of disclosure should not be construed as reflecting an intention to claim more features than are expressly recited in each claim. Rather, as reflected in the appended claims, inventive aspects exist in fewer features than all the features of a single foregoing disclosed embodiment. Therefore, the claims appended following the detailed description are thus explicitly incorporated into this detailed description, wherein each claim itself represents a separate embodiment of the invention.

[0056] Furthermore, although some embodiments described herein include some features included in other embodiments but not in other embodiments, combinations of features from different embodiments are intended to fall within the scope of the invention and form different embodiments as will be understood by those skilled in the art. For example, any embodiment of the claimed embodiments in the appended claims may be used in any combination.

[0057] Numerous specific details are set forth in the description provided herein. However, it should be understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description.

[0058] In embodiments of the present invention, the reference to "position sensing system" refers to a system comprising components such as a magnetic structure and a sensor device, the sensor device including a sensor for detecting parameters or a set of parameters associated with the position of a moving target, the moving target giving rise to relative motion between the structure and the sensor. These sensors may include sensing elements that provide a signal (e.g., an electrical signal) proportional to one or more detected parameters. The parameter may be, for example, a component of a magnetic field. Thus, the position sensing system provides signals that can be processed to obtain the position of a target. These signals can be processed by a processor, such as a microelectronic processor, a monolithic integrated microprocessor, etc. Within the framework of the present invention, a position sensor can be defined as a position sensing system combined with a processor for processing signals from the system.

[0059] This invention relates to a position sensing system for measuring the position of a target. Figure 1 A prior art position sensor 10 is shown, including one or more magnetic field sensors integrated in a chip 11, and a magnetic structure 12, thereby forming a sensing system 13, wherein one of the sensors or the structure moves with a target while the other remains stationary. Figure 1In the exemplary sensor 10, the target is an axis 20, which rotates about its axis 21, and a magnetic structure 12 (such as a disk) is attached to the axis 20, which rotates with it, while the chip 11 is stationary. For example, it may be attached to a housing (not shown). The relative position of the sensor and the structure can be measured by measuring the magnetic field generated by the magnetic structure 12 and the change of that magnetic field at the location of the sensor chip 11. The sensor can measure the polarity (north or south) and flux of the field, indicating how close the location is to the center of a particular pole or to the boundary of another pole. The sensor may include several sensing elements for measuring different magnetic components of the vector field, thus improving localization. Signals from the sensor chip 11 can be processed by a processor 14, which can calculate the position of the magnet based on the field sensed at the location of the sensor chip 11.

[0060] This disclosure can be applied to moving magnetic structures relative to fixed sensors or to static magnetic structures and sensors that move relative to magnetic structures.

[0061] For example, in the case of a sensing system used to sense angular position, a conventional rotary encoder with a simple dipole magnet and a magnetic sensing element can provide absolute angular position because both the orientation and value of the field are measured by the magnetic sensing element, and these same parameters are configured to repeat every full revolution. Therefore, the measurement will give an accurate angle within one revolution (360°).

[0062] However, the resolution in state-of-the-art position sensors is limited to 0.02° or 14 bits, and the angular accuracy varies with temperature by approximately 0.3 degrees, including temperature drift, signal-to-noise ratio, positioning error, etc. This limitation is caused by the relative mechanical positioning of the magnet and the magnetic sensor, as well as by the signal-to-noise ratio. Using multipole magnets (comprising multiple dipoles, e.g., multiple dipoles each having a north and south pole) is an available solution to improve both resolution and angular accuracy. Multipole magnets will be referred to simply as "multipole" below. In a multipole, each dipole covers a portion of the structure (e.g., a 360° fully rotated subdivision), allowing the field to vary more with motion, thus improving the accuracy of the magnetic sensor. In this way, if the field strength of both signals is maintained, the resolution of accuracy can be directly improved by the number of pole pairs applied. Therefore, for 8 pole pairs, the accuracy can be improved by up to 8 times.

[0063] On the other hand, by using the multipole method, direct information about the absolute position is lost because the pole pairs are repeated in each subdivision. Although the angle is accurately measured in that subdivision or angular sector (e.g., a 45° sector for 8 pole pairs), the angular sector cannot be identified solely based on the multipole method.

[0064] To overcome this problem, existing systems use a composite magnetic structure formed by two magnetic tracks. As used herein, the term "track" as part of a magnetic source typically refers to a ring-shaped, toroidal, or cylindrical object when discussing angular position sensor systems, and to a bundle-shaped object when discussing linear position sensor systems.

[0065] The magnetic structure includes a first or main orbit and a second orbit (also called a nonius orbit). The main orbit is a multipole orbit with a predetermined number of dipoles, and the nonius orbit is a multipole orbit with a different number of pole pairs than the main orbit (typically fewer pole pairs) (accuracy is less critical than with the main orbit, thus simplifying the design). The field generated by each orbit is sensed by a corresponding magnetic sensor. By combining the measured signals, an angular position within a 360° rotation can be retrieved. The number of pole pairs for each orbit and their differences can be adapted to optimize the calculation of the angular position. For example, given that the main orbit has n pole pairs, the nonius orbit typically has n-1 pole pairs, but in common designs and also in some embodiments of the invention, it has more than one dipole. Notably, the nonius orbit and the main orbit comprise the same type of magnetic material and have substantially the same size, therefore the magnetic flux is substantially the same. The difference in field strength or magnetic flux sensed by the first and second sensors is due to the different relative positions of the poles along the magnetic structure, which is because the main orbit and the nonius orbit have different numbers of poles. Therefore, in the prior art, the flux of the poles in the main orbit and the Nonius orbit is essentially the same.

[0066] Examples of these tracks are as follows: Figure 2 As shown. The top magnetic source 30 is a structure comprising two concentric orbits located in a single plane for use as an angular position sensor. The magnetic sensor device 31 can be arranged above or below this plane. In the example, the first orbit 32 is formed by an outer ring with five pole pairs, and the second orbit 33 is formed by an inner ring with four pole pairs. These rings are preferably axially magnetized. When there is relative rotational motion between the sensor and the source 30, for each rotation, the sensor device 31 senses eight poles with the inner orbit sensor and ten poles with the outer orbit sensor.

[0067] The central diagram shows a magnetic structure 40, which includes two cylindrical tracks 42 and 43 with the same radius and a sensor device 41 arranged as a satellite. The sensor device 41 can move around these cylindrical tracks (or, while the sensor device 41 remains fixed, the cylinder rotates about its center perpendicular to the axial direction A).

[0068] The bottom figure illustrates a magnetic structure 50 for a linear position sensor. The magnetic structure 50 includes a magnetic sensor device 51 located in a single plane and two parallel linear tracks 52 and 53, with the sensor device 51 arranged above or below this plane. The first track 52 may be formed by a first multipole magnet having five pole pairs, and the second track 53 by a second multipole magnet having four pole pairs. These magnets are preferably magnetized in the height direction H. When there is relative motion between the magnetic sensing system and the magnetic structure along the longitudinal direction L, the sensing system, as previously described, will sense the five N poles and five S poles of the first track, and the four N poles and four S poles of the second track.

[0069] As mentioned above, the magnetic sensor device includes a first sensor and a second sensor for a corresponding track, and these sensors provide magnetic field measurements in at least two different directions. For example, each sensor is adapted to provide measurements of magnetic fields in at least two different directions. For example, each sensor device includes at least two magnetic sensing elements, the elements of the first sensor being configured to measure at least two first orthogonal magnetic field components (typically referred to as By1, Bz1) at a first sensor position (P1) above the first magnetic track, and the elements of the second sensor being configured to measure at least two second orthogonal magnetic field components (typically referred to as By2, Bz2) at a second sensor position (P2).

[0070] Below, refer to Figures 3 to 10 Let's illustrate several magnetic sensor devices. Note that the Z-direction follows the direction from the sensor to the magnetic structure. This corresponds to the axial direction in a coplanar magnetic structure and the radial direction in the case of a stacked cylindrical magnetic structure.

[0071] Figure 3 A schematic representation of sensor device 820a is shown, wherein a first magnetic sensor and a second magnetic sensor at positions P1 and P2 are spaced apart along the X-axis at a predefined distance Δx. Each sensor includes four horizontal magnetic sensing elements, such as Hall elements H1-H4 arranged near the periphery of integrated flux concentrators IMC1 and IMC2. Three orthogonal magnetic field components Bx, By, and Bz can be measured at each position P1 and P2, as described in more detail in disclosure EP3650816A1. The components are obtained from the difference or summation of signals from different elements (such as the difference between Bx1 and the signals of H1-H3 as a ratio). Therefore, sensor device 820a has eight magnetic sensing elements capable of measuring two sets of three orthogonal magnetic field components, namely (Bx1, By1, Bz1) at the first sensor position P1 and (Bx2, By2, Bz2) at the second sensor position P2.

[0072] Figure 4Another sensor device is shown, comprising two magnetic sensors spaced apart at a predefined distance Δx. Each sensor includes a structure comprising a horizontal Hall effect sensor (for measuring Bz) and two vertical Hall effect sensors (one for measuring Bx and one for measuring By). Therefore, the magnetic sensor device 820b is also capable of measuring three orthogonal magnetic field components: (Bx1, By1, Bz1) at the first sensor position P1 and (Bx2, By2, Bz2) at the second sensor position P2.

[0073] Figure 5 The sensor device also includes two sensors spaced apart at a predefined distance Δx. Each sensor comprises a structure consisting of only two horizontal Hall elements arranged on opposite sides of the IMC disk and located on a virtual line perpendicular to the X-axis. Each sensor structure is capable of measuring two orthogonal components By and Bz at each of the sensor positions P1 and P2. This sensor device advantageously requires only four horizontal Hall elements instead of eight.

[0074] Figure 6 Another sensor device is shown, comprising two magnetic sensor structures spaced apart at a predefined distance Δx. Each sensor structure includes a horizontal Hall element and a vertical Hall element. Each sensor structure is capable of measuring two orthogonal components, By and Bz. It eliminates the need for an integrated magnetic flux concentrator, thus making it easier to manufacture.

[0075] Since two orthogonal components can be used to retrieve the absolute position, these types of sensors that provide two orthogonal components are sufficient.

[0076] Figure 7 It shows Figure 3 A variant of, and Figure 8 It shows Figure 4 A variant of . Figure 7 and Figure 8 Each of the sensor devices includes four sensors spaced apart in the X and Y directions, instead of just two. These devices are not only able to measure the three orthogonal components (Bx1, By1, Bz1) at P1 and another three orthogonal components (Bx2, By2, Bz2) at P2, but also able to determine the spatial gradients of Bx, By, and Bz at the two sensor locations P1 and P2 as dBx / dy, dBy / dy, and dBz / dy, respectively.

[0077] Although the setup is more complex, gradient signals are useful because they are highly insensitive to external disturbance fields, and therefore the overall angular position will also be highly insensitive to external disturbance fields.

[0078] The gradient signals dBy / dy and dBz / dy can then be converted into two sets of quadrature signals, for example, using a set of linear or polynomial equations with a relatively small number of coefficients (e.g., predefined coefficients), which can be determined (e.g., after assembly) by simulation or by measurement. The coefficients can be stored in non-volatile memory, such as in a processing unit like a microprocessor. A first angle α1 relative to the inner ring and a second angle α2 relative to the second ring can then be calculated based on the arctangent function of the quadrature signals.

[0079] It should be noted that obtaining the gradient signal is optional; for example, in Figures 3 to 6 In this context, the two components (e.g., By and Bz) may be out of phase and do not require a gradient signal.

[0080] Figure 9 yes Figure 7 A simplified diagram of the sensor device, where the X-axis component and gradient dBx / dy are not obtained for each sensor. It is similar to... Figure 5 The sensor equipment is further capable of measuring the magnetic field gradient signals dBy / dy and dBz / dy. Similarly, Figure 10 yes Figure 8 A simplified diagram of the sensor device, where the X-axis component and gradient dBx / dy are not obtained for each sensor. It is similar to... Figure 6 The sensor device is further capable of measuring the magnetic field gradient signals dBy / dy and dBz / dy.

[0081] Functionally speaking, Figure 3 , Figure 5 , Figure 7 and Figure 9 The sensor devices are respectively similar to Figure 4 , Figure 6 , Figure 8 and Figure 10 Sensor devices.

[0082] A drawback of multi-track designs is the significant overlap (or crosstalk) between the magnetic fields generated by the first and second tracks. Crosstalk is low in the component parallel to the direction established between the magnetic structure and the sensor, or the Z-direction, but typically much higher in the field component orthogonal to the Z-direction. To address this, in existing technologies, the track and sensor positions must be sufficiently spaced to allow for individual readouts, so that each sensor can obtain a signal with low crosstalk from its corresponding track. This may require the use of several sensor platforms or large semiconductor chips, which is expensive. Alternatively, crosstalk can be corrected computationally.

[0083] Signal processing will be discussed in more detail in the examples below. Generally, each sensor is adapted to measure field components with different orientations, such as two orthogonal field components near the corresponding track. Therefore, four signals are obtained from the field (two from each sensor location), but readings from sensors adjacent to each track are affected by crosstalk from other tracks. Mathematical correction requires solving a linear regression problem. This provides two out-of-phase components for each track. From this, principal and nonius angles are obtained, which are then combined again to provide uncalibrated absolute angles. Final calibration can be provided to eliminate nonlinearities such as mechanical misalignment or imperfections in the magnet.

[0084] However, this method requires complex data processing because the principal angle and the nonius angle can only be reconstructed from a continuous linear combination of all four input signals. Furthermore, the coefficients used for the principal angle will only be valid for the precisely calibrated position. Even slight misalignments will introduce errors into the calibrated angle.

[0085] This invention provides a system, a sensor, and a method for position sensing that reduces crosstalk between the fields generated by a main orbit and those generated by a nonius orbit. This is accomplished without the need for separate sensing elements, allowing the magnetic sensing system to be housed in a relatively small chip, thus reducing costs. This is achieved by adapting a magnetic structure in which the main orbit generates a much stronger magnetic field than the nonius orbit, for example, at least twice as strong. Therefore, a first sensor detects the field generated by the stronger first magnetic track, while the contribution of the weaker second magnetic track detected by the first sensor to this magnetic field is negligible. To determine fine angles, once the position of the nonius orbit is obtained, it is not necessary to use four input signals in a linear combination to obtain fine angles, thus the sensing is less sensitive to misalignment. Complex calculations are not required during motion; they are only required when the sensing system is "started up."

[0086] Magnetic structures in which the main orbit generates a field much stronger than that of the Nonius orbit can be realized in different ways. The extrema in the main orbit are likely to be physically larger. However, the invention is not limited thereto, and the sizes of the main orbit and the Nonius orbit can be similar (such as...). Figure 2 The structure shown is shown, but the poles provided in the main orbit are made of a different magnetic material than those in the nonius orbit (or both the size and material of the poles can be different).

[0087] In a first aspect, the present invention provides a sensing system comprising a magnetic structure having a primary orbit and a nonius orbit, and corresponding sensors for measuring the field approaching each orbit. The magnetic structure is adapted such that a first sensor senses the magnetic field of most of the primary orbit, such that ignoring the field from the nonius orbit does not affect the accuracy of the measurement. At least two sensors may be housed in the same sensor chip. The magnetic structure is not rotationally symmetric over 360 degrees (in other words, the magnetic structure has one-fold rotational symmetry, so the field is identical only after a 360-degree rotation). For example, the primary orbit and the nonius orbit have different numbers of poles, resulting in one-fold symmetry in the field; typically, the primary orbit has more poles than the nonius orbit (e.g., one more pole).

[0088] In some embodiments, as explained above, each sensor is adapted to provide a measurement of the orthogonal components of the magnetic field. In some embodiments, at least two sensors may be included in the reference. Figures 3 to 10 In any of the magnetic sensor devices discussed. These figures illustrate various examples of sensor devices that can be used in embodiments of the invention, but the invention is not limited thereto, and other sensor structures, such as those including magnetoresistive elements, may also be used.

[0089] The predefined distance Δx between the sensors can be a value in the range of approximately 1.0 mm to approximately 3.0 mm, for example, approximately 1.5 mm to approximately 2.5 mm, or equal to approximately 2.0 mm. The predefined distance Δy between two pairs of sensors can be a value in the range of approximately 0.5 mm to approximately 3.0 mm. As mentioned above, Δy (which will be oriented in the circumferential direction of the magnetic source) can be greater than or less than Δx (which will be oriented in the radial direction of the magnetic source).

[0090] A better and simpler approach is to implement the magnetic structure of the sensing system because the main orbit provides a stronger magnetic field, for example, two or three times, or even five or ten times, higher than the Nonius orbit. This allows for less crosstalk at the first sensor (at position P1 facing the main orbit).

[0091] By utilizing the constraint of a small distance between these magnetic sensors (e.g., both sensors are mounted on the same sensor device, e.g., a chip), the relative positioning of the first and second magnetic sensors can be optimized to reduce crosstalk. Typically, the distance between the first sensor and the Nonius orbit should be greater than the distance between the second sensor and the Nonius orbit.

[0092] In some embodiments, the first sensor is additionally closer to the main orbit than to the NONUS orbit. In some embodiments of the invention, the top projection of the first sensor overlaps with the main orbit, and the second sensor is at least equidistant from both the main orbit and the NONUS orbit, preferably closer to the NONUS orbit than to the main orbit. The top projection of the second sensor may overlap with the NONUS orbit; alternatively, the top projection of the second sensor may overlap with the gap in the nonmagnetic material between the main orbit and the NONUS orbit. The invention is not limited to these configurations, and the top projection of the second sensor may overlap with the main orbit. In some embodiments, the top projection of the midpoint between the first and second sensors does not overlap with the NONUS orbit.

[0093] Position sensors with this sensing system provide position sensing with less computational load during measurement, as will be seen below.

[0094] In some embodiments, each magnetic dipole of the main orbit provides a magnetic field in which the component measured is at least twice as high as that of each of the magnetic dipoles of the Nonius orbit.

[0095] The magnetic field (e.g., the maximum value of the flux norm) can be compared for each orbit that is substantially at the same location relative to other orbits (e.g., above the center of the magnetic poles and on the centerline of the orbit at a similar air gap (where Bz is maximum), or between two opposing poles on the centerline of the orbit at a similar air gap (where Bx is maximum)). Alternatively, the maximum value of the flux norm at any location above each orbit at a similar air gap can also be considered. The fact that the magnetic field of the main orbit is larger (at least twice as large) due to the size of the poles, the magnetic material of the poles, or both depends on the magnetic rails themselves, not on the placement of sensors, etc. In some embodiments, the air gap can be at least 0.3 mm and up to 5 mm.

[0096] For example, the fields of each orbit can be compared at relative sensor positions. The position P1 of the first sensor is farther from the Nonius orbit than the position P2 of the second sensor. The magnetic flux generated from the Nonius orbit at the position P1 of the first sensor can be at least half to one-tenth of the value of the magnetic flux generated from the main orbit at the position P2 of the second sensor, for example, at least half, or one-third, or one-quarter, or one-fifth, or one-sixth, or one-tenth. In contrast, in the prior art, these values ​​are substantially equal. The effect is that even if crosstalk may increase at the second position P2, crosstalk at the first position P1 will be reduced. A surprising effect is that the overall determination of absolute position is improved, rather than allowing crosstalk variations to cancel each other out or even worsen the determination of absolute position.

[0097] With appropriate adaptation, the present invention can be applied to linear or rotatable systems. Hereinafter, details of the invention will be explained with reference to a sensing system suitable for measuring the angular position of a rotating system. For example, the main track and the nonius track are concentric tracks rotatable about a common axis of rotation, thus allowing the position of the rotating system, such as the angular position of a rotating system (e.g., a rotor), to be obtained.

[0098] In some embodiments, the main track and the nonius track are rectangular toroidal surfaces.

[0099] In some embodiments, the main track and the nonius track are coplanar tracks with axial magnetization. The sensor can be placed above or below the track, in a plane parallel to the track, so that the Z component of the field is axial. For example, the sensor chip can include all sensors, such as sensors that can be monolithically integrated with a chip parallel to the track. In this way, the rotational motion of the track relative to the sensor is detected as a changing magnetic field and its orientation.

[0100] Specifically, for practical reasons, the Nonius orbit can be enclosed by the main orbit, since the Nonius orbit is usually smaller than the main orbit (with fewer pole pairs).

[0101] As previously mentioned, the primary orbit provides a much stronger magnetic field than the nonius orbit; for example, the maximum magnetic flux density is twice as strong, or, for example, three or six times stronger, for at least two components of the field (e.g., two orthogonal components of the field). In some embodiments, the primary orbit is made of a magnetic material with a magnetization greater than that of the nonius orbit. Many combinations are conceivable, such as neodymium-based magnets for the primary orbit and ferrite magnets for the nonius orbit. In some embodiments, the two orbits may comprise neodymium-based alloys with different magnetic material contents. For example, the first orbit may comprise a high content of FeNdB or almost entirely FeNdB, while the second orbit comprises FeNbB in a plastic matrix (also known as a plastic-bonded magnet), thus reducing the magnetic material content and final strength of the second orbit. The magnetic structure can be configured as follows: Figure 2 As in the illustrated embodiment, the magnetic material of the adapted poles is such that the poles in the main orbit are much stronger than those in the nonius orbit (providing a higher magnetic flux).

[0102] Alternatively or additionally, the relative size and geometry of the magnets can be adapted to achieve the desired effect. For example, in at least one dimension, the primary orbit may include a magnet larger than the Nonius orbit. For example, as Figure 11As shown in the embodiments of the present invention, the tracks 101 and 102 of the magnetic structure 100 may have the same thickness and be made of the same material, which provides mechanical advantages in a rotatable system (e.g., uniform distribution when the magnetic structure is movable). However, the width of the first track or main track 101 is at least twice the width of the coplanar nonius track 102, for example, three times the width of the coplanar nonius track, or at least six times the width of the coplanar nonius track. The invention is not limited thereto, and the shape, size, and material of the poles in the main track may differ from those in the nonius track.

[0103] Figure 11 A main track 101 with eight pole pairs 103 is shown, where each black area represents either the N or S pole. A nonius track 102 has seven pole pairs 104, with a magnet much smaller than that of the main track. As this magnetic structure rotates about its center in a plane perpendicular to axis A, sensors at positions P1 and P2 adjacent to the main track and nonius track, respectively, receive signals from pole pairs 103 of the main track 101 and pole pairs 104 of the nonius track 102. For example, the position P1 of the first sensor may overlap with the first track. For example, the position P2 of the second sensor may not overlap with the second track; for example, the position P2 of the second sensor may pass through the adjacent region between the first and second tracks, for example, as... Figure 11 As shown, the position P2 of the second sensor can overlap with the uncoded region 108. The position P2 of the second sensor can be at least equidistant from both orbits, closer to the Nonius orbit; the position P2 of the second sensor can overlap with the Nonius orbit. Position P2 can also overlap with the main orbit. This is not limited to... Figure 11 The planar geometry can be any magnetic structure geometry according to embodiments of the invention. It should be noted that the overlap direction follows the distance from the respective sensor to the magnetic structure. Figure 11 In this case, the overlap occurs from a top-down perspective.

[0104] Since the magnets are much larger for the main orbit, the signal from the magnets (pole pair 104) in the Nonius orbit can be ignored. As previously mentioned, the magnetic flux density of the axial and tangential components sensed by the sensors can be twice that of the Nonius orbit for the main orbit, for example, for the maximum magnetic flux density of said components, or by comparing the field of the main orbit at position P2 of the second sensor with the field of the Nonius orbit at position P1 of the first sensor. This can be applied to other configurations of the magnetic tracks and different components of the magnetic field.

[0105] For example, the area of ​​the first orbital is five times larger than that of the second orbital, such as 20 times larger, or 10 times larger. Typically, the first orbital can be, for example, 5 to 50 times larger than the second orbital, or 10 to 30 times larger. Figure 12 It has specific measurements Figure 11A top view of the magnetic structure. Nevertheless, other parameters, dimensions, and geometries can also be used. A sensor device 105 is shown, positioned to receive a large signal from the main track, with the first and second sensors positioned at position P2 such that their Z-direction does not intersect the main track.

[0106] This invention is not limited to a coplanar arrangement. For example, it can use, as shown in the example below. Figure 13 The embodiment shows a cylindrical arrangement in which the tracks of structure 200 are stacked rings in the axial direction (A). For example, the thickness of the main track 201 (in the axial direction) can be greater than the thickness of the nonius track 202. As previously mentioned, the dimensions can be adjusted to obtain the desired ratio of the magnetic field generated by the tracks. For example, particularly for the components related to the sensor relative to sensor device 205, the magnetic material of the main track can be stronger than the magnet of the nonius track, having a higher maximum magnetic flux density. Sensor device 205 is positioned such that sensor device 205 senses the periphery of the tracks, with a first sensor close to the main track 201 and a second sensor away from the main track 201 and close to the nonius track 202. Figure 11 The first sensor can overlap with the main track (in Figure 13 In the side view of the case, following the distance between the sensor device 205 and the magnetic structure 200 (in this case, radial), the second sensor may be located on the codeless area, or at the same distance from both tracks, preferably closer to the nonius track, for example, overlapping with the nonius track. Under certain spatial constraints, this positioning of the sensor device on one side of the sensing system may be ideal.

[0107] Figure 14 An exemplary embodiment of a linear sensing system for linear position measurement is also shown, wherein the magnetic structure 300 includes parallel first linear tracks 301 and second linear tracks 302, wherein the dipole distribution and sensor device 305 are as shown in reference. Figure 2 It is placed as defined in the bottom diagram.

[0108] In these figures, the width of the tracks of the composite magnetic structure is defined in the radial direction R in the coplanar tracks, in the axial direction A in the stacked cylindrical tracks, and in the transverse direction T in the linear tracks.

[0109] In order to show the required magnetic fields and their ratios for the main orbit and the Nonius orbit, in Figure 11 , Figure 13 and Figure 14In some embodiments, the width of the main orbit is at least twice the width of the nonius orbit, for example, at least three times (e.g., six times) the width of the nonius orbit. However, as previously stated, the invention is not limited thereto, and the magnetic material of the main orbit may be adapted, or other geometries (e.g., different thicknesses) may be provided to provide the desired magnetic field configuration.

[0110] In all these examples, the relative position between the first sensor and the magnetic structure is measured. For example, a moving target whose position is to be measured moves together with a first track and a second track; for instance, the moving target may be attached to tracks fixed to each other and / or to a track fixed to the moving target, and the magnetic sensing system is fixed, similar to... Figure 1 The system (replacing the magnetic structure 12 and sensor device or chip 11 with a sensing system according to an embodiment of the invention). Alternatively, the magnetic structure is static, and the magnetic sensing system moves together with the target (e.g., attached to the target). For example, it can be a chip attached to the target. In any case, the main track and the nonius track do not move relative to the other track. In embodiments of the invention, the magnetic structure is a magnetic element in which the tracks are fixed to each other. In some embodiments of the invention, the structure includes a gap between the first track and the second track. The gap can be filled with a non-magnetic material. The presence of the gap reduces crosstalk between the magnetic structures.

[0111] The air gap can be defined as the shortest distance between the sensor and the track, for example, a plane containing the track surface. This plane can be... Figure 13 The curved surface of the cylindrical setting is tangent, or in Figure 11 and Figure 14 In the case of a planar track, the plane of the track facing the sensor is tangent. The system is arranged such that the sensor is coplanar and parallel to the plane containing the track surface, so the air gap for each sensor can be substantially the same. The air gap can be on the order of about 0.3 mm to about 5.0 mm, for example, between 0.8 mm and 3 mm.

[0112] In another aspect, the present invention provides a position sensor including a position sensing element according to an embodiment of the first aspect of the invention. The position sensor further includes a processing means, such as a processing unit or processor, that can be coupled to a sensing system. For example, the processor may be an external module that can be connected to or be connected to the signal output of a magnetic sensor. The processor may be included as a component together with the magnetic sensor; for example, the magnetic sensor and the processor may be monolithically integrated on the same chip, etc. However, this is not necessary, and the processing may be performed by an external processor, microprocessor, or microcontroller located outside the sensor device (e.g., physically outside the sensing system).

[0113] Figure 12A position sensor 400 according to an embodiment of the present invention is illustrated. The position sensor 400 includes a sensing structure and a processing means 106 adapted to process signals from a sensor device 105 (e.g., a sensor chip). This processing means may be, for example, a processor (e.g., a microelectronic processor connected to the sensor of the sensor device 105), which may include computing power, programmability, memory (e.g., for lookup tables), etc. The processing means 106 may be a separate module, or the processing means 106 may be monolithically integrated with the sensor device 105.

[0114] In some embodiments of the invention, the processing unit may include a connection for the output unit 107 (e.g., a memory, display, interface, etc.). For example, the output unit 107 may include a controller coupled to or connected to the processing device 106, so that the controller can receive signals from the processor and control the device accordingly, for example, the controller can control the power supply of the motor that moves the target to which the magnetic structure 100 is attached, based on feedback from a position sensor mounted in the motor. However, the invention is applicable to other functions and devices.

[0115] In some embodiments of the invention, the processing device 106 (e.g., a processing unit) may also include internal memory and / or connections to retrieve information from a table (e.g., a LUT), for example, for calibrating a position sensor.

[0116] In some embodiments, a processing unit (e.g., a processor) may be adapted to perform calculations using measurements from a first and a second sensor when the sensing system is started up (e.g., when the sensors of the sensing system are powered on). This results in a first absolute position. After the sensors are started up, the processor may be adapted to subsequently process the signal from the first sensor, while ignoring the signal from the second sensor. The resulting processed signal is used to update the position information obtained at startup, thereby providing the subsequent absolute position. The processor may be adapted to periodically repeat this process, processing only the signal from the first sensor (and thus ignoring the signal from the second sensor based on the Nonius orbit) and updating the previously obtained absolute position information, thereby updating the absolute position with each periodic measurement. The complex calculations using the inputs of both sensors advantageously only need to be performed once when the position sensor is started up (or activated).

[0117] The processor includes contacts or inputs to receive signals from a first sensor and a second sensor, and processes the signals to provide a position sensor. Signal processing can be performed according to the methods discussed below.

[0118] In a further aspect, a method for position measurement is provided. Measuring the motion of a target includes relating the motion to be measured to the relative motion of a magnetic structure (including a first multipole track and a second multipole track) with respect to a first sensor and a second sensor, as previously described. The method may include providing a main track, where the magnetic flux is at least twice the flux of the magnetic field produced by the Nonius track. The method includes using the first sensor to read the magnetic field at a first location adjacent to the first track (or main track), thereby obtaining a first signal. For example, the first sensor may be placed closer to the main track than to the Nonius track. The method includes using a second sensor to read the magnetic field at a second location, thereby obtaining a second signal, where the second location does not overlap with the main track, for example, the second location is adjacent to the second track (or Nonius track). The second sensor may be placed closer to the main track than to the Nonius track.

[0119] The method may include using a magnetic sensor device, such as a sensor chip including a first sensor and a second sensor. The method includes using a first track and a second track, which have different numbers of poles and move together (both having the same speed and direction of motion). In some embodiments, the method may include using a sensing system according to a first aspect of the invention and processing the sensor signals with a processor. The method steps including signal processing can be implemented as an algorithm in the processor.

[0120] The method includes using signals from a first sensor and a second sensor to obtain quadrant information, or in other words, information relating to which quadrant of the target (e.g., which quadrant in 360°, or, for an octapole multipole, which of the eight 45° quadrants) is facing the sensor. This provides coarse information about the general location of the magnetic structure. The method also includes using only the signal from the first sensor to obtain the precise location (e.g., angle) in the quadrant. Combining the coarse and precise location information allows for the accurate retrieval of the absolute location (e.g., absolute angle) of the magnetic structure.

[0121] Figure 15 This is a signal processing scheme that includes the main orbit and the Nonius orbit. The magnetic component and the orthogonal component are measured at the sensor location in the direction between the magnetic structure and the sensor. In this particular embodiment, a coplanar magnetic structure can be assumed to be used, thereby sensing the axial component Mx and the tangential component Mt. The axial and tangential signals are provided by at least two sensing elements adapted to sense the axial and tangential components of the field, respectively.

[0122] The second sensor provides similar measurements (signals) at a location adjacent to the Nonius orbit, which is closer to the Nonius orbit than to the main orbit. A similar discussion regarding the second sensor can be made as previously described for the axial signal Nx and the tangential signal Nt.

[0123] In the first example, crosstalk between the magnetic field generated by the main orbit and the magnetic field generated by the Nonius orbit at the location of either sensor can be considered, since the sensors are positioned very close to each other, for example, on a single chip, or integrated into a single chip. As mentioned earlier, separating the sensors is possible, which may introduce new problems. It is economically advantageous if the sensors are located on a single chip (e.g., a semiconductor chip).

[0124] Quadrature components can be obtained from measurements as a linear combination of different measured components (e.g., axial and tangential components).

[0125] In embodiments of the invention, the out-of-phase signals originate from sensing elements spaced apart at specific distances, rather than from orthogonal components or gradients. In some embodiments, the sensing elements may be matched to half of their respective pole spacings. For example, if two Bz sensing elements spaced apart by half the pole spacing on the main orbit and two other Bz sensing elements spaced apart by half the pole spacing on the nonius orbit (four Bz sensing elements), then even if a single component is sensed (sensed at two locations instead of one), the signals in each pair will be out of phase.

[0126] The principal axial signal Mx and the principal tangential signal Mt can be written as field components B, respectively. a_主 B t_主 Furthermore, the Nonostic signals Nx and Nt can also be written as B. a_诺纽斯 B t_诺纽斯 .

[0127] 1)Sin(N pp *x)=A1*B t_主 +A2*B a_主 +A3*B t_诺纽斯 +A4*B a_诺纽斯

[0128] 2) Cos(N) pp *x)=A5*B t_主 +A6*B a_ Main + A7*B t_ Nonius + A8 * B a_诺纽斯

[0129] 3)Sin((N pp -1)*x)=A9*B t_主 +A 10 *B a_主 +A 11 *B t_诺纽斯 +A 12 *B a_诺纽斯

[0130] 4) Cos((N) pp -1)*x)=A 13 *B t_主 +A 14 *B a_主 +A 15 *B t_诺纽斯 +A 16 *B a_诺纽斯

[0131] The main track has a predetermined number N pp The Nonnius orbit has one less pole than the main orbit (N). pp -1 pole). The first two combinations 1) and 2) are the out-of-phase components (Sin and Cos) of the main orbit, and these components include the crosstalk component from the second sensor (corresponding to the Nonius orbit). The other two combinations 3) and 4) are components of the Nonius orbit, and also include the components from the measurement of the first sensor due to the aforementioned crosstalk.

[0132] Therefore, the principal orbital angle MALC is obtained as components 1) and 2) from the linear combination LC of all four signals. The nonius angle NA is also obtained as components 3) and 4) from the linear combination of all four signals. The principal pole counter MPC is obtained by combining the principal angle MA with the nonius angle NA. It provides information related to the sector of the structure (from which the sensor is receiving the magnetic field). For example, in the case where the angle is in the range of 0° and 360°, combining MPC with MALC again delivers the (uncalibrated) absolute position UA1. A final calibration CAL can be applied (e.g., using a lookup table LUT) to compensate for mechanical or magnetic irregularities, thereby obtaining the absolute angle ABS. A linear regression operation and further calculations are required for each continuous measurement obtained by the sensor, for example, periodically every tenths of a second. This is a computationally intensive operation that slows down position detection. However, calibration and regression can be performed only once, and then the measurements provided by the first sensor can be easily used to update the position information. In other words, since the quadrants are initially obtained using the Nonius position, the quadrant information can be updated after the relative motion indication has been transferred from one quadrant to another, which can be tracked by measurements on the first track.

[0133] In embodiments of the invention, the magnetic configuration of the main orbit relative to the Nonius orbit results in a signal from the first sensor with significantly less crosstalk than that from the Nonius orbit's magnetic field. This allows measurements from the second sensor to be ignored. This simplification is achieved by the invention, and can be performed in different ways through signal processing.

[0134] In some embodiments, linear regression is performed as previously shown to obtain the absolute angle. However, the present invention allows the signal from the second sensor (nonius signal) to be ignored in this calculation. For example, Figure 16 This is a scheme of the method according to an embodiment of the present invention. As previously described, the first sensor provides two orthogonal signals Mx and Mt, which correspond to the field at a location closer to the main orbit than to the Nonius orbit. The second sensor provides two orthogonal signals Nx and Nt, which may correspond to the same orientation as the orthogonal signals of the first sensor. These are generated by the field at a location closer to the Nonius orbit than to the main orbit.

[0135] Then, as previously described, linear regressions are obtained from these signals, resulting in a set of four equations as shown above.

[0136] However, in embodiments of the invention, the calculation of the first two equations 1) and 2) of the main track does not require the use of measurements from the second sensor. This is due to... Figure 16 The shaded arrows indicate this. In the specific algorithms shown above with equations 1), 2), 3), and 4), the coefficients A3, A4, A7, and A8 are set to 0.

[0137] In other words, using the structure as described in the embodiments of the present invention allows for the following simplifications:

[0138] 1)Sin(N pp *x)=A1*B t_主 +A2*B a_主

[0139] 2) Cos(N) pp *x)=A5*B t_主 +A6*B a_主

[0140] 3)Sin((N pp -1)*x)=A9*B t_主 +A 10 *B a_主 +A 11 *B t_诺纽斯 +A 12 *B a_诺纽斯

[0141] 4) Cos((N) pp -1)*x)=A 13 *B t_主 +A 14 *B a_主 +A 15 *B t_诺纽斯 +A 16 *Ba_诺纽斯

[0142] However, it should be noted that the linear regression of the second sensor can still be severely affected by crosstalk from the stronger main orbit, so the signal from the first sensor can be taken into account in the calculation (Equations 3 and 4).

[0143] The principal angle and nonius angle are obtained from Sin and Cos by calculating the corresponding modified Arctan function.

[0144] After solving the linear regression to obtain the principal angle MA and the nonius angle NA, the principal pole counter MPC and the uncalibrated angle UA can be obtained:

[0145] MPC = int(MA - NA - MA / N) pp )

[0146] UA = MPC * 360 / N pp +MA / N pp

[0147] The final calibration CAL can be provided, for example, by calculating or using a LUT to eliminate nonlinearities such as mechanical misalignment or defects in the magnet, thereby providing a calibrated absolute angle ABS. The number of points used in the LUT is equal to 16*N. pp This serves as a useful trade-off between resolution and the number of calibration points. However, other numbers of points can be used, such as in 4*N. pp and 32*N pp Between. These equations can be solved periodically.

[0148] These specific equations and algorithms illustrate the impact of the invention on signal processing; however, the invention is not limited to these specific algorithms or specific orthogonal components of the field to provide position measurements.

[0149] For example, instead of axial and lateral components, different components, such as radial and lateral components, can be used. For example, if using... Figure 13 This is likely the case if the tracks are stacked as shown in the diagram. For example,... Figure 14 In the linear embodiment of the sensing system shown, the components can also be components in the height H direction and the linear L direction. In this case, different algorithms can be used, but the readings of the second sensor can still only be used when measuring the position of a specific dipole in the track (master pole counter), and can be ignored when measuring the position relative to that specific dipole (absolute position).

[0150] In some embodiments, the master pole counter (initial master pole counter, MPCS) is obtained from the first and second sensors upon startup of the sensing system. This can be achieved, for example, by following a simplified linear regression calculation as previously described. Once this has been completed at startup, subsequent measurements require only the signal from the first sensor. Since the initial measurement allows determination of the sector from which the first sensor is sensing the magnetic field (distinguishing the poles), and since the influence of the nonius orbit is negligible, the operational master pole counter (MPCO) can be simply updated using further accurate measurements from the first sensor without having to recalculate the MPC according to the aforementioned linear regression. Figure 16 As shown, for updating the MPC, it is not necessary to use the signal from the second sensor until the next possible startup, or the MPC may be readjusted after, for example, several revolutions, to re-determine or verify the location of the magnetic structure sector affecting the sensor.

[0151] In some embodiments, the sensing system is activated simultaneously with the movement of the target. For example, a device such as a motor (including the sensor of the present invention) may be rotating, and the method can be performed by obtaining the principal angle and nonius angle at startup (when the sensor is turned on) while the motor is running. In some embodiments, the measurement of the absolute position (including taking into account the signal from the second sensor) may be performed before the normal movement of the device begins, for example before the movement of the engine begins.

[0152] This invention provides precise measurements from the main orbit, which defines the overall measurement accuracy. Measurements from the Nonius channel do not need to be as precise, as these are only used to distinguish absolute position. Measurements at a second position (using a second sensor on the Nonius orbit) can accommodate some crosstalk from the main orbit.

Claims

1. A sensing system for sensing position, comprising: A first magnetic rail for generating a magnetic field and a first sensor for sensing a magnetic field, the first magnetic rail comprising a first number of multipoles; A second magnetic rail for generating a magnetic field and a second sensor for sensing a magnetic field, the second magnetic rail comprising a second number of multipoles, the second number being different from the first number; The first magnetic rail and the second magnetic rail are firmly fixed to each other, thereby forming a magnetic structure; Wherein, the first sensor is positioned closer to the first magnetic track than closer to the second magnetic track, and the second sensor is positioned closer to the second magnetic track, wherein the distance between the first sensor and the second magnetic track is greater than the distance between the second sensor and the second magnetic track, and wherein the magnetic flux density generated by the first magnetic track and the second magnetic track at similar air gaps on the respective centerlines of the first magnetic track and the second magnetic track follows a ratio of 2 or higher.

2. The sensing system as described in claim 1, characterized in that, The first magnetic track and the second magnetic track are concentric tracks that can rotate around a common axis of rotation.

3. The sensing system as described in claim 2, characterized in that, The first magnetic track and the second magnetic track are coplanar tracks, wherein the second magnetic track is enclosed by the first magnetic track, wherein the first magnetic track has a first predetermined width and the second magnetic track has a second predetermined width, and the first predetermined width is at least twice the size of the second predetermined width.

4. The sensing system as described in claim 2, characterized in that, The first magnetic rail and the second magnetic rail are stacked rings with the same outer radius, wherein the width of the first magnetic rail defined in the axial direction is at least twice the width of the second magnetic rail.

5. The sensing system as described in claim 1 or 2, characterized in that, The first magnetic track is a multipole track with at least 8 dipoles.

6. The sensing system as described in claim 1 or 2, characterized in that, The first sensor and the second sensor are adapted to sense different field components.

7. The sensing system as described in claim 1 or 2, characterized in that, The first sensor and the second sensor are integrated into a single semiconductor chip.

8. The sensing system of claim 1, further comprising a signal processing means for processing signals from the sensor, and further comprising a signal output for providing the absolute position of the first magnetic track relative to the sensor.

9. The sensing system as described in claim 8, characterized in that, The processing device is adapted to calculate the initial position based on the measurement of the second sensor when the sensing system is started.

10. The sensing system as described in any one of claims 8 or 9, characterized in that, The processing device is adapted to obtain the position using measurement signals from the first sensor and the second sensor, and to calibrate the position.

11. A method for sensing position using the sensing system of claim 1, the method further comprising retrieving measurements from the first sensor and the second sensor, and calculating the position of the magnetic structure relative to the first sensor.

12. The method of claim 11, further comprising subsequent calibration results for compensating for mechanical misalignment.

13. The method of claim 11, further comprising: The position of the first magnetic track is detected by using measurements from the first and second sensors to detect the dipoles of the magnetic structure, while ignoring measurements from the second sensor to detect the absolute position of the first sensor relative to the magnetic structure. The sensor is located on the magnetic structure.

14. The method as described in claim 13, characterized in that, The method further includes performing the detection of the position and absolute position of the dipole when the sensor is activated, and performing a measurement of the dipole of the magnetic structure by using the first sensor to retrieve the dipole of the magnetic structure, ignoring the signal of the second sensor in subsequent measurements after the initial position of the first magnetic track is detected, the sensor being located on the magnetic structure.

15. The method of any one of claims 11 to 12, further comprising: The position of the first magnetic track is detected by performing a linear combination of the measurements from the first and second sensors, which are located above the magnetic structure, using measurements from the first and second sensors to detect the dipoles of the magnetic structure and to detect the absolute position of the first sensor relative to the magnetic structure.

Images