inductive angle sensor and torque sensor
Patent Information
- Application Number
- CN202410334043.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2023-03-24
- Filing Date
- 2024-03-22
- Publication Date
- 2026-10-09
- Estimated Expiration
- 2044-03-22
Smart Images
Figure CN118687598B_ABST
Abstract
Description
Technical Field
[0001] This invention generally relates to the field of inductive angle sensors and inductive torque sensors, and more specifically, to an inductive angle sensor and an inductive torque sensor, which are of the type including a transmitter coil, a first set of receiver coils, a first movable coupling element, a second set of receiver coils, and a second movable coupling element. This invention also relates to a printed circuit board suitable for an inductive angle sensor or an inductive torque sensor. Background Technology
[0002] Inductive angle sensors are known in the art. They offer the advantage of being able to measure angular position without physical contact, thereby avoiding problems such as mechanical wear, scratches, and friction. They typically consist of an excitation coil (also called a "transmitter coil") and multiple detection coils (also called "receiver coils"). The excitation coil generates an alternating magnetic field that is coupled to a set of receiver coils depending on the angular position of the coupling element. The signals obtained from the receiver coils are processed in electronic circuitry, and the angular position is determined based on these signals.
[0003] This invention relates to an inductive angle sensor having two sets of receiver coils, two movable elements, and electronic circuitry for determining the angle between these movable elements. When these coupling elements are connected to a torsion bar, the angle between the coupling elements is related to the torque applied to the torsion bar.
[0004] US2010319467(A1) discloses an inductive torque sensor for motor vehicles, which includes at least one excitation coil, at least one oscillator circuit, a stator circuit board, at least two rotors, and an evaluation device.
[0005] There is always room for improvement or replacement. Summary of the Invention
[0006] The object of embodiments of the present invention is to provide an inductive angle sensor, a torque sensor including such an angle sensor, and a printed circuit board used in such an angle sensor.
[0007] The object of embodiments of the present invention is to provide an inductive angle sensor and / or torque sensor that, compared with existing solutions of similar size (e.g., the same diameter of the coupling element), has one or more of the following characteristics: the same or improved measurement range, the same or improved accuracy (e.g., the same or reduced error), and preferably all of these characteristics.
[0008] The purpose of embodiments of the present invention is to provide an inductive angle sensor and / or torque sensor that has a smaller size (e.g., a smaller diameter of the coupling element) compared to existing solutions with similar measurement range and / or similar accuracy (e.g., similar error).
[0009] The purpose of embodiments of the present invention is to provide an inductive angle sensor and / or torque sensor that has similar size and similar accuracy compared to existing solutions, but is less complex and / or has lower cost and / or is easier to manufacture.
[0010] The purpose of embodiments of the present invention is to provide an inductive sensor and / or torque sensor suitable for use in an automotive environment.
[0011] The purpose of embodiments of the present invention is to provide an inductive sensor and / or torque sensor suitable for use in industrial or robotic environments.
[0012] These objectives are achieved through embodiments of the present invention.
[0013] According to a first aspect, the present invention provides an inductive angle sensor, comprising: at least one transmitter coil (e.g., TX) for generating an alternating magnetic field; at least one excitation circuit for generating an alternating signal to energize the at least one transmitter coil; a first set of receiver coils (e.g., Rx1a, Rx1b, Rx1c), each receiver coil having a geometry with a first periodicity N; a second set of receiver coils (e.g., Rx2a, Rx2b, Rx2c), each receiver coil having a geometry with a second periodicity M, the second periodicity M being less than the first periodicity N; and an evaluation circuit for evaluating the signal from the first set of receiver coils. The signals obtained from the first and second set of receiver coils; a first movable coupling element (also referred to as the "first target") for providing inductive coupling between at least one transmitter coil (e.g., TX) and the first set of receiver coils (e.g., Rx1a, Rx1b, Rx1c), the first coupling element having a periodic geometry with the first periodicity N; a second movable coupling element (also referred to as the "second target") for providing inductive coupling between at least one transmitter coil and the second set of receiver coils (e.g., Rx2a, Rx2b, Rx2c), the second coupling element having a periodic geometry with the second periodicity M; wherein the ratio N / M of the first periodicity N to the second periodicity M is equal to 1.5.
[0014] The inventors were surprised to find that the accuracy of this inductive angle sensor was much higher than that of an inductive angle sensor with essentially the same angular range but with an integer ratio between the first periodicity and the second periodicity, because not only would the signal-to-noise ratio (SNR) be better, but especially because the crosstalk would be much lower.
[0015] The second coupling element can move relative to the first coupling element to form an angle between them.
[0016] At least one transmitter coil and multiple receiver coils can be implemented on a single substrate (e.g., a printed circuit board, PCB) or on two separate PCBs.
[0017] In one embodiment, the inductive angle sensor includes only a single transmitter coil, which is arranged to generate a magnetic field to be received by both a first set of receiver coils and a second set of receiver coils.
[0018] In one embodiment, the inductive angle sensor includes two transmitter coils, one for generating a magnetic field to be received by a first set of receiver coils, and the other for generating a magnetic field to be received by a second set of receiver coils.
[0019] In this embodiment, the excitation circuit and the evaluation circuit are implemented in an integrated semiconductor device (also known as a “chip”).
[0020] The evaluation unit can be configured to determine a first angle value based on signals obtained from a first set of receiver coils, and to determine a second angle value based on signals obtained from a second set of receiver coils, and optionally, to determine the angle difference between the first and second angle values. The evaluation unit can also be configured to determine a torque value based on the angle difference.
[0021] The integrated semiconductor device can output one or more of a first angle value, a second angle value, an angle difference (if determined), and a torque value (if determined).
[0022] An inductive angle sensor may include a single transmitter coil, typically used for a first set of receiver coils and a second set of receiver coils. Alternatively, an inductive angle sensor may include two transmitter coils, one for the first set of receiver coils and one for the second set of receiver coils.
[0023] In an embodiment, the evaluation circuit is configured to determine a first angle value (α1) based on signals obtained from a first set of receiver coils, and to determine a second angle value (α2) based on signals obtained from a second set of receiver coils, and to determine the difference between the first angle value (α1) and the second angle value (α2).
[0024] In this embodiment, the first periodicity N is equal to 6, and the second periodicity M is 4.
[0025] In this embodiment, the first periodicity N is equal to 9, and the second periodicity M is 6.
[0026] In this embodiment, the first periodicity N is equal to 12, and the second periodicity M is 8.
[0027] In this embodiment, the first periodicity N is equal to 15, and the second periodicity M is 10.
[0028] In the embodiment, the first periodicity N is equal to 18, and the second periodicity M is 12.
[0029] Combinations with (N=6, 9, or 12) are particularly suitable for automotive applications because, in addition to the advantages mentioned above, they offer a relatively large measurement range: ±15° (for N=6, M=4), ±10° (for N=9, M=6), and ±7.5° (for N=12, M=8).
[0030] Having a combination of (N=6 or N=9) is particularly advantageous because the measurement range includes not only the functional range (typically ±5%), but also an additional range for functional safety.
[0031] In one embodiment, the first set of receiver coils has a two-phase loop structure, and the second set of receiver coils also has a two-phase loop structure.
[0032] In one embodiment, the first set of receiver coils has a two-phase loop structure, and the second set of receiver coils has a three-phase loop structure.
[0033] In one embodiment, the first set of receiver coils has a three-phase loop structure, and the second set of receiver coils has a two-phase loop structure.
[0034] In one embodiment, the first set of receiver coils has a three-phase loop structure, and the second set of receiver coils also has a three-phase loop structure.
[0035] In one embodiment, at least one of the first set of receiver coils and the second set of receiver coils has a three-phase loop structure; and at least one transmitter coil, the first set of receiver coils, and the second set of receiver coils are implemented on a single multilayer printed circuit board.
[0036] The advantage of this embodiment is that the second harmonic of the signal induced by one set of coils will be regarded as 3.0 times or 1.33 times the harmonic frequency by another set of coils, but is not sensitive to this frequency. The multilayer printed circuit board may also include the above-described integrated semiconductor device.
[0037] Preferably, a multilayer PCB is arranged between the first movable coupling element and the second movable coupling element. By doing so, the distance between the coil and the corresponding movable coupling element can be reduced, while the received signal is sufficiently large, and the physical gap (air gap) between the PCB and the movable element is large enough to avoid contact.
[0038] In this embodiment, the multilayer PCB is a six-layer PCB. The first set of receiver coils may be implemented primarily on two adjacent layers, and the second set of receiver coils may be implemented primarily on two other adjacent layers, with the two inner layers primarily used for shielding purposes (e.g., to prevent or reduce crosstalk).
[0039] In this embodiment, the printed circuit board is a four-layer printed circuit board.
[0040] Surprisingly, it was found that if the ratio between the periodicities is a factor of 1.5, and at least one of the first and second receiver coils is implemented using a three-phase loop structure, a six-layer PCB is not required, although in fact the second (and sixth) harmonics of the signal induced in the first coil may be considered as third (and ninth) harmonic interference in the second coil (due to the ratio of 1.5), since the three-phase loop structure is essentially insensitive to the third and ninth harmonics.
[0041] According to a second aspect, the present invention also provides an inductive torque sensor, comprising: a torsion bar; an inductive angle sensor according to the first aspect; wherein a first movable coupling element and a second movable coupling element are connected to the torsion bar (e.g., at opposite ends of the torsion bar).
[0042] The actual torque value can be calculated by the evaluation circuit and can be output by the integrated semiconductor device. Alternatively or additionally, the evaluation circuit can output two angular positions and / or the difference between them, or the torque value can be calculated externally to the evaluation circuit (e.g., in an electronic control unit (ECU) connected to the integrated semiconductor device).
[0043] According to a third aspect, the present invention also provides a printed circuit board (e.g., suitable for an inductive angle sensor according to the first aspect, or an inductive torque sensor according to the second aspect), the printed circuit board comprising: at least one transmitter coil (e.g., TX) for generating an alternating magnetic field; a first set of receiver coils (e.g., Rx1a, Rx1b, Rx1c), each receiver coil having a geometry with a first periodicity N; and a second set of receiver coils (e.g., Rx2a, Rx2b, Rx2c), each receiver coil having a geometry with a second periodicity M, the second periodicity M being less than the first periodicity N; wherein the printed circuit board comprises only four layers; and the ratio N / M of the first periodicity N to the second periodicity M is equal to 1.5.
[0044] In this embodiment, the first periodicity N is equal to 6, and the second periodicity M is 4.
[0045] In this embodiment, the first periodicity N is equal to 9, and the second periodicity M is 6.
[0046] In this embodiment, the first periodicity N is equal to 12, and the second periodicity M is 8.
[0047] In this embodiment, the first periodicity N is equal to 15, and the second periodicity M is 10.
[0048] In the embodiment, the first periodicity N is equal to 18, and the second periodicity M is 12.
[0049] In an embodiment, the printed circuit board further includes: at least one excitation circuit for generating an alternating signal to energize the at least one transmitter coil; and an evaluation circuit for evaluating signals obtained from a first set of receiver coils and a second set of receiver coils.
[0050] In one embodiment, at least one excitation circuit and an evaluation circuit are implemented in a single integrated circuit device, which is mounted on a printed circuit board.
[0051] According to a fourth aspect, the present invention also provides an inductive angle sensor, comprising: at least one transmitter coil for generating an alternating magnetic field; at least one excitation circuit for generating an alternating signal for energizing the at least one transmitter coil; a first set of receiver coils, each receiver coil having a geometry with a first periodicity N; a second set of receiver coils, each receiver coil having a geometry with a second periodicity M, the second periodicity M being less than the first periodicity N; an evaluation circuit for evaluating signals obtained from the first set of receiver coils and the second set of receiver coils; and a first movable coupling element for... Inductive coupling is provided between at least one transmitter coil and a first set of receiver coils, the first coupling element having a periodic geometry with the first periodicity N; a second movable coupling element for providing inductive coupling between at least one transmitter coil and a second set of receiver coils, the second coupling element having a periodic geometry with the second periodicity M; wherein the ratio N / M of the first periodicity N to the second periodicity M is a non-integer value selected from the group consisting of 4 / 3, 6 / 5, 5 / 2 and 7 / 2; and wherein at least one transmitter coil, the first set of receiver coils, and the second set of receiver coils are implemented on a single four-layer printed circuit board.
[0052] Optionally, at least one of the first set of receiver coils and the second set of receiver coils has a three-phase loop structure.
[0053] It can be shown that an inductive angle sensor with a first set of receiver coils and a second set of receiver coils having a ratio N / M equal to one of these values has many of the same properties as an inductive angle sensor with N / M = 1.5, particularly regarding negligible crosstalk. Since no shielding layer is required, multiple coils can be implemented on a four-layer PCB. This makes the solution easier to manufacture (compared to a six-layer PCB) and thus cheaper.
[0054] According to a fifth aspect, the present invention also provides an inductive torque sensor, comprising: a torsion bar; an inductive angle sensor according to a fourth aspect; wherein a first movable coupling element and a second movable coupling element are connected to the torsion bar (e.g., at opposite ends of the torsion bar).
[0055] The evaluation circuit can be configured to output a signal indicating the actual torque (e.g., the angle difference mentioned above), which is typically proportional to the actual torque.
[0056] According to a sixth aspect, the present invention also provides a printed circuit board suitable for an inductive angle sensor according to a fourth aspect or an inductive torque sensor according to a fifth aspect, the printed circuit board comprising: at least one transmitter coil for generating an alternating magnetic field; a first set of receiver coils, each receiver coil having a geometry with a first periodicity N; a second set of receiver coils, each receiver coil having a geometry with a second periodicity M less than the first periodicity N; wherein the printed circuit board comprises only four layers; and the ratio N / M of the first periodicity N to the second periodicity M is a non-integer value selected from the group consisting of 3 / 2, 4 / 3, 6 / 5, 5 / 2 and 7 / 2.
[0057] Optionally, at least one of the first set of receiver coils and the second set of receiver coils has a three-phase loop structure.
[0058] In one embodiment, the first set of receiver coils has a three-phase loop structure, and the second set of receiver coils has a two-phase loop structure.
[0059] In one embodiment, the first set of receiver coils has a two-phase loop structure, and the second set of receiver coils has a three-phase loop structure.
[0060] In one embodiment, the first set of receiver coils has a three-phase loop structure, and the second set of receiver coils also has a three-phase loop structure.
[0061] In this embodiment, the ratio is 2.5, N is 15, and M is 6.
[0062] In an embodiment, the printed circuit board further includes: at least one excitation circuit for generating an alternating signal to energize the at least one transmitter coil; and an evaluation circuit for evaluating signals obtained from a first set of receiver coils and a second set of receiver coils.
[0063] In one embodiment, at least one excitation circuit and an evaluation circuit are implemented in a single integrated circuit device, which is mounted on a printed circuit board.
[0064] Specific and preferred aspects of the invention are set forth in the appended independent and dependent claims. Features from the dependent claims may be suitably combined with features of the independent claims and other dependent claims, and not merely as expressly set forth in the claims. These and other aspects of the invention will be apparent from the embodiments(s) described herein, and are elucidated with reference to the embodiments(s) described herein. Attached Figure Description
[0065] Figure 1A A schematic representation of a torque sensor according to an embodiment of the present invention is shown. It includes an angle sensor according to an embodiment of the present invention, and a torsion bar mounted to an input shaft portion and an output shaft portion.
[0066] Figure 1B An illustrative example of a first coupling element with N leaves (in the example: N = 9) is shown.
[0067] Figure 1C An illustrative example of a printed circuit board including multiple coils is shown.
[0068] Figure 1D An illustrative example of a second coupling element with M leaves (M = 6 in the example) is shown.
[0069] Figure 2A It shows Figure 1B An illustrative example of a first coupling element, which is movably mounted relative to a substrate comprising at least one transmitter coil and a first set of receiver coils. These receiver coils have the same periodicity as the first coupling element (in the example: N = 9).
[0070] Figure 2B It shows Figure 1D An illustrative example of a second coupling element, which is movably mounted relative to a substrate comprising at least one transmitter coil and a second set of receiver coils. These receiver coils have the same periodicity as the second coupling element (in the example: M = 6).
[0071] Figure 3 A high-level block diagram of an electronic circuit that can be used in embodiments of the present invention is shown.
[0072] Figure 4A The diagram shows a graph illustrating that an inductive angle sensor with (N=9, M=6) and an inductive angle sensor with (N=18, M=9) have the same measurement range (i.e., 20° or ±10°).
[0073] Figure 4B Five illustrative combinations of angles for N and M are shown, as may be used in embodiments of the invention.
[0074] Figure 5 A graph showing the typical signal strength of the signal obtained from the receiver coil as a function of periodic variation is shown.
[0075] Figure 6 A curve is shown that illustrates the typical noise level (in arbitrary units) varying according to the periodicity (or number of leaves) of the coupling element and receiver coil.
[0076] These figures are illustrative only and are not restrictive. In the figures, some elements may be enlarged and not drawn to scale for illustrative purposes. No reference numerals in the claims should be construed as limiting the scope. In different figures, the same or similar reference numerals (e.g., the same module 100) generally refer to the same or similar elements. Detailed Implementation
[0077] 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.
[0078] 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 temporal, spatial, hierarchical, or any other order. It should be understood that the terms thus used are interchangeable where appropriate, and the embodiments of the invention described herein can operate in an order different from that described or illustrated herein.
[0079] The terms top, bottom, 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 the terms used so are interchangeable where appropriate, and the embodiments of the invention described herein can operate in orientations different from those described or illustrated herein.
[0080] It should be noted that the term "comprising" as used in the claims should not be construed as limiting itself to the means listed thereafter; it does not exclude other elements or steps. Therefore, the term should be interpreted as specifying the presence of the features, integers, steps, or components stated as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the scope of the statement "a device comprising means A and B" should not be limited to a device consisting solely of components A and B. It means that, for the purposes of this invention, the only relevant components of the device are A and B.
[0081] 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 all of the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, as will be apparent to those skilled in the art from this disclosure, particular features, structures, or characteristics may be combined in any suitable manner.
[0082] 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 streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, this method of disclosure should not be construed as reflecting an intention to claim more features than are expressly recited in each claim. Rather, as reflected in the appended claims, the inventive aspect lies in fewer features than all the features of a single foregoing disclosed embodiment. Thus, the claims appended to the Detailed Description are thereby expressly incorporated into this Detailed Description, wherein each claim itself represents a separate embodiment of the invention.
[0083] Furthermore, while some embodiments described herein include features found in other embodiments but not in those 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.
[0084] Numerous specific details are set forth in the specification 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 specification.
[0085] In this document, the terms "excitation coil" and "transmitter coil" have the same meaning.
[0086] In this document, the terms "receiver coil" and "detection coil" have the same meaning.
[0087] In this document, the terms “coupled element”, “target”, and “rotor” have the same meaning.
[0088] In this document, depending on the context, the expression "first coil group" may refer to a "first group of receiver coils" with or without at least one transmitter coil.
[0089] In this document, depending on the context, the expression "second coil group" may refer to a "second group of receiver coils" with or without at least one transmitter coil.
[0090] In this document, the "periodicity" of a movable target can refer to the number of leaves.
[0091] In this document, the “mechanical angle” of a movable target can be calculated as the “electrical angle” of the movable target divided by its periodicity.
[0092] In this document, sqrt() refers to the square root function.
[0093] This invention relates to an inductive angle sensor having two sets of receiver coils and two (e.g., of a type similar to that described in US2010319467(A1)) movable coupling elements. For ease of discussion, it will be assumed that the first target has a first periodicity N (e.g., N leaves) and the second target has a second periodicity M (e.g., M leaves), where N and M are integer values. US2010319467(A1) states that the value of N is an integer multiple of M, and the preferred ratio of N / M is equal to 2.0. Examples are given of an inductive sensor with a 15° angular periodicity and (N = 30, and M = 15) and another inductive sensor with a 20° angular periodicity and (N = 18, and M = 9). Such combinations are said to produce small measurement errors.
[0094] The inventors of this invention sought to find an inductive angle sensor that has a similar measurement range without significantly increasing measurement error.
[0095] They began experimenting and were surprised to find that, considering all relevant factors, an inductive angle sensor of similar size (e.g., the same target outer diameter) but with a ratio N / M equal to 1.5 produced a lower measurement error compared to a prior art sensor with the same measurement range and a ratio (N / M = 2). This was unexpected. Or in other words, they found that an inductive angle sensor with the same measurement range and the same measurement error could be implemented in a smaller size or form factor and thus at a lower cost. This was a significant surprise, especially considering that the automotive market is highly competitive and that US2010319467(A1) had been published more than 12 years prior.
[0096] The principles of the invention will be explained in more detail below. The prior art sensor described above, in which N=18 and M=9 (wherein the ratio N / M=2), will be referred to as a "reference sensor".
[0097] Now refer to the attached diagram.
[0098] Figure 1A A schematic representation of a torque sensor 100 is shown, which includes an angle sensor 101 and a torsion bar 141. The torsion bar 141 may be connected at one end to an input shaft 142 and at the other end to an output shaft 143.
[0099] Angle sensor 101 includes:
[0100] At least one transmitter coil (e.g., only one transmitter coil, or two transmitter coils Tx1, Tx2) is used to generate an alternating magnetic field. The at least one transmitter coil may have a substantially circular shape (e.g., as shown in the image). Figure 2A and Figure 2B (as shown in the illustration);
[0101] At least one excitation circuit 321 (see example) Figure 3 The at least one excitation circuit 321 is used to generate an alternating signal (e.g., a sinusoidal current) for energizing the at least one transmitter coil;
[0102] The first group of receiver coils Rx1a, Rx1b, and Rx1c each have a geometry with a first periodicity N, for example, two receiver coils phase-shifted relative to each other in the case of a two-phase system, or three receiver coils phase-shifted relative to each other in the case of a three-phase system.
[0103] The second group of receiver coils (Rx2a, Rx2b, Rx2c) each has a geometry with a second periodicity (M), which is smaller than the first periodicity (N).
[0104] Evaluation circuit 320, which is used to evaluate the signals obtained from the first set of receiver coils and the second set of receiver coils;
[0105] A first movable coupling element 131 (also referred to as a "first target" or "first rotor") is used to provide inductive coupling between at least one transmitter coil and a first set of receiver coils. The first coupling element 131 has a periodic geometry with the first periodicity N. Figure 1D In the example, the first coupling element has a nine-leaf (N=9) shape, which are spaced apart angularly in multiples of 360° / 9=40°;
[0106] A second movable coupling element 132 (also referred to as a "second target" or "second rotor") is used to provide inductive coupling between at least one transmitter coil and a second set of receiver coils. The second coupling element 132 has a periodic geometry with the second periodicity M. Figures 1B to 1D In the example, the second coupling element has a six-leaf (M=6) shape, which are spaced apart angularly in multiples of 360° / 6=60°;
[0107] The ratio of the first periodicity N to the second periodicity M is 1.5.
[0108] It is worth noting that a single transmitter coil is sufficient to excite two movable targets.
[0109] In one embodiment, the transmitter coil has an overall circular shape. Alternatively, the transmitter coil has an overall C-shape.
[0110] As by Figure 1A This indicates that the first target 131 is located at a distance "g" from the first set of coils, and the second target 132 is located at a distance "g" from the second set of coils. In a preferred embodiment, "g" is a value ranging from 0.1 to 5.0 mm, or from 0.5 to 4.0 mm, for example, from 1.0 to 3.0 mm, or from 1.5 to 2.5 mm (e.g., equal to about 2.0 mm). The smaller the "g" value, the stronger the signal obtained from the receiver coil, and thus the higher the signal-to-noise ratio (SNR), but the smaller the mechanical tolerances (i.e., the higher requirements) to avoid mechanical friction.
[0111] Figure 1B An illustrative example of a first coupling element with N leaves is shown. In the example shown, N equals 9.
[0112] Figure 1C It shows a combination of multiple coils ( Figure 1C Not explicitly shown, but see, for example Figure 2A and Figure 2B An illustrative example of a printed circuit board PCB 110. The PCB may also include excitation circuitry 321 and evaluation circuitry 320, preferably integrated in a single semiconductor device 128 (e.g., as shown in the image). Figure 3 (As shown in the diagram). The PCB is typically mounted securely to a frame (not shown).
[0113] Figure 1D An illustrative example of a second coupling element with M leaves (M = 6 in the example) is shown.
[0114] exist Figures 1A to 1D In the example shown, a first target 131 with periodicity N is located on the side of the output shaft 143, and a second target 132 with periodicity M is located on the side of the input shaft 142. However, the invention is not limited to this, and it is of course possible to connect the first target 131 to the input shaft 142 and the second target 132 to the output shaft 143.
[0115] exist Figure 1B In the example, the PCB has a specific shape with a rectangular portion at the bottom and a semi-circular portion at the top, but the invention is not limited to this, and other shapes are possible. The PCB can be a single six-layer PCB, wherein the first set of coils is implemented in a configuration positioned... Figure 1AIn the two layers on the left, near the first target 131, and where the second set of coils is implemented in a location where... Figure 1A Of the two layers on the right, located near the second target 132, two inner layers serve as shielding elements. These shielding elements reduce crosstalk between the first target and the first set of coils on one hand, and reduce crosstalk between the second target and the second set of coils on the other hand.
[0116] Figure 2A It shows Figure 1B An illustrative example of first coupling elements 131, 231, which are movably mounted relative to transmitter coil Tx1 and a first set of receiver coils Rx1a, Rx1b, Rx1c. These coils can be implemented in a printed circuit board (e.g., as shown in the image). Figure 1C As shown in the diagram, but Figure 2A (Not explicitly shown). Receiver coils Rx1a, Rx1b, and Rx1c have the same periodicity N as the first coupling element 231. Figure 2A In the specific example shown, the first periodicity N is equal to 9, but the invention is not limited thereto, and other values of N are also possible (see, for example...). Figure 4B ).
[0117] exist Figure 2A In the example shown, the first set of receiver coils includes three receiver coils, Rx1a, Rx1b, and Rx1c, spaced 120° apart. The signals obtained from these three receiver coils can be decoded using a three-phase system. However, the invention is not limited to this, and it is also possible to use a first set of receiver coils with only two receiver coils (not shown) spaced 90° apart. The signals obtained from these two receiver coils can be decoded using a two-phase system. Two-phase and three-phase decoding systems are well known in the art and are not the primary focus of this invention; therefore, they do not require further detailed description here.
[0118] Figure 2B It shows Figure 1D An illustrative example of second coupling elements 132, 232, which are movably mounted relative to the transmitter coil Tx2 and the second set of receiver coils Rx2a, Rx2b, Rx2c. These coils can be implemented on the same printed circuit board as the first set of receiver coils, or on a separate printed circuit board. Receiver coils Rx2a, Rx2b, Rx2c have the same periodicity M as the second coupling element 232 (M = 6 in the example, but other values are possible, see example...). Figure 4B ).
[0119] exist Figure 2BIn the example shown, the second set of receiver coils includes three receiver coils spaced 120° apart from each other, forming a three-phase coil system. However, the invention is not limited to this, and it is also possible to use a second set of receiver coils with only two receiver coils (not shown) spaced 90° apart.
[0120] In one embodiment, the first set of receiver coils comprises two coils phase-shifted relative to each other by 90°, and the second set of receiver coils also comprises two coils phase-shifted relative to each other by 90°.
[0121] In one embodiment, the first set of receiver coils comprises two coils phase-shifted relative to each other by 90°, and the second set of receiver coils comprises three coils phase-shifted relative to each other by 120°.
[0122] In one embodiment, the first set of receiver coils comprises three coils phase-shifted relative to each other by 120°, and the second set of receiver coils comprises two coils phase-shifted relative to each other by 90°.
[0123] In one embodiment, the first set of receiver coils comprises three coils phase-shifted relative to each other by 120°, and the second set of receiver coils also comprises three coils phase-shifted relative to each other by 120°.
[0124] Readers unfamiliar with coil layouts may refer to EP3885711(A1), which is incorporated herein by reference in its entirety, but the invention is not limited thereto and other coil layouts may also be used.
[0125] Figure 3 A high-level block diagram of an electronic circuit that can be used in embodiments of the present invention is shown, but the invention is not limited thereto, and other circuits may also be used.
[0126] Figure 3 The electronic circuitry comprises two main sub-circuits: an excitation circuit 321 and an evaluation circuit 320. In Figure 3 In the example, these sub-circuits are implemented in a single integrated semiconductor device 328, but this is not an absolute requirement, and the stimulation can also be performed by a separate circuit (e.g., by a separate chip).
[0127] Figure 3The electronic circuitry is connected to at least one transmitter coil (schematically illustrated by a single black rectangle Tx), but as explained above, it is also possible to use two discrete transmitter coils Tx1, Tx2. In this case, the two transmitter coils are preferably driven by a single excitation signal (e.g., by connecting the two transmitter coils in series or parallel). The transmitter coil TX may be part of the excitation circuit 321, but this is not absolutely required. The transmitter coil Tx can be excited at a frequency of about 1 MHz to about 20 MHz. The excitation frequency may be higher than, lower than, or substantially equal to the resonant frequency of the oscillator circuit. These aspects are well known in the art and are not the main focus of the present invention, and therefore do not require further explanation here.
[0128] Figure 3 The electronic circuitry is also connected to the first set of receiver coils (schematically illustrated by three black rectangles Rx1a, Rx1b, Rx1c) and also to the second set of receiver coils (schematically illustrated by three black rectangles Rx2a, Rx2b, Rx2c). Circuitry 328 is configured to receive signals from each set of receiver coils and optionally to amplify these signals using amplifiers 322a, 322b, and to decode the received signals in a known manner (e.g., by demodulating the received signals to baseband signals). Demodulation may include synchronous rectification and low-pass filtering. The demodulated signals may be further processed using analog or digital circuitry systems, including, for example, an analog-to-digital converter 327, a digital processor 326 (e.g., a DSP), and a controller 325 connected to a non-volatile memory 324 (e.g., flash memory).
[0129] Evaluation circuit 320 can be configured to determine a first mechanical angle value α1 based on signals obtained from a first set of receiver coils and a first period N (e.g., by determining a first electrical angle based on the received signal and dividing that electrical angle by the first period N), and to determine a second mechanical angle value α2 based on signals obtained from a second set of receiver coils and a second period M (e.g., by determining a second electrical angle based on the received signal and dividing that electrical angle by the second period M). The relative position between the two targets can be calculated based on the difference between values α1 and α2. This relative position indicates the torque applied to torsion bar 141 (e.g., proportional to it). The angle difference and / or torque value can be calculated internally by evaluation circuit 320 and output to an external processor (e.g., output to an electronic control unit (ECU, not shown) connected to circuit 328). Alternatively or additionally, angles α1 and α2 can be output, and the angle difference and / or torque can be calculated by said external processor.
[0130] It should be noted that, Figure 3The electronic circuit architecture shown is merely an example of how to process the signal obtained from the receiver coil to obtain the angle value, but the invention is not limited thereto, and other architectures may also be used.
[0131] Figure 4A A graph, unknown in the prior art but proposed by this invention, is shown, illustrating the measurement range for several combinations of the first periodicity N and the second periodicity M. The inventors discovered that having a... Figure 1A The measurement range of an inductive angle sensor with a first periodicity N and a second periodicity M, as shown in the diagram, can be expressed by the following formula:
[0132] Measurement range = 360° / LCM(N,M)[1]
[0133] LCM is the least common multiple of the values N and M.
[0134] More specifically, Figure 4A Two "curves" are shown:
[0135] The curve above (black) shows that for the second period, the value of M is fixed at 6, and the measurement range varies according to the first period, N. It can be seen that the curve provides several relatively high peaks (indicated by "X"), namely for N=12 (which is 2*6), for N=18 (which is 3*6), and for N=24 (which is 4*6), and so on.
[0136] The curve below (gray) shows that for the second period, the value of M is fixed at 9, and the measurement range varies according to the first period, N. It can be seen that the curve also provides several relatively high peaks, namely for N=18 (which is 2*9) and for N=27 (which is 3*9), and so on.
[0137] The inventors were surprised to find that the curve above showed additional peaks for N=9 and M=6, where the N / M ratio was 1.5. From Figure 4A It can be understood that the ±10° range achievable by the inductive angle sensor with (N=9, M=6, ratio=1.5) proposed in this invention, and indicated by the circle, is the same as the measurement range of the classic inductive angle sensor with (N=18, M=9, ratio=2) and the classic inductive angle sensor with (N=18, M=6, ratio=3).
[0138] This observation illustrates a first insight into the invention, but does not provide any clues about the accuracy or error obtained through such a sensing angle system.
[0139] Before describing accuracy or error Figure 4BA table listing the angular ranges for five illustrative combinations of N and M is provided, as may be used in embodiments of the invention. It will be understood that...
[0140] i) The combination proposed in this invention (N=6, M=4, ratio=1.5) provides the same range (i.e., ±15°) as that achievable by a classical sensor with (N=12, M=6, ratio=2), and
[0141] ii) The combination proposed by this invention (N=9, M=6, ratio=1.5) provides the same range (i.e., ±10°) as that achievable by a classical sensor having (N=18, M=9, ratio=2), and
[0142] iii) The combination proposed by this invention (N=12, M=8, ratio=1.5) provides the same range (i.e., ±7.5°) as that that can be obtained by a classical sensor with (N=24, M=6, ratio=4), etc.
[0143] These examples demonstrate that the same range can be achieved using a smaller periodicity with a ratio of N / M = 1.5, compared to existing solutions using integer ratios N / M = 2 or higher. For comparable-sized inductive angle sensors, this translates to a stronger signal, lower noise, and lower sensitivity to misalignment, with only a slight reduction in resolution.
[0144] It should be noted that the measurement range can vary depending on the application. For example, measuring steering wheel torque in an automotive application might require a measurement range of at least 10°, or at least 15°, or at least 20°. Smaller measurement ranges may be suitable for other applications (e.g., certain robotics and / or industrial applications). It should be noted in this regard that... Figure 4B The list is not exhaustive, and further combinations of N and M can be easily found, where N and M are integer values with a ratio of 1.5.
[0145] However, an important second insight of this invention is understanding and being able to quantify, such as Figure 1A The error (or accuracy) of the inductive angle sensor of the type illustrated in the figure has various values of a first periodicity N and a second periodicity M (e.g., as shown in the figure). Figure 4B (Listed in).
[0146] Existing solutions seem to select values for N and M to maximize sensor resolution within a given measurement range. A typical measurement range for automotive applications is ±10°. While "high resolution" is important, other factors also crucial for good performance of inductive angle sensors are noise and crosstalk. Each of these factors will be explained in more detail below.
[0147] i) First factor: Range and resolution
[0148] The first receiver coil and the first movable element have a first periodicity N. The second receiver coil and the second movable element have a second periodicity M. As mentioned above, the measurement range is 360° divided by the least common multiple of N and M.
[0149] The resolution of the differential angle is determined by the smaller of the values N and M, which in turn is determined by M. Resolution is typically defined as the mechanical angle corresponding to 1 LSB (least significant bit). For a given evaluation circuit (e.g., an ADC with a predefined number of bits, e.g., 12 bits), higher periodicity results in higher resolution. More specifically, when using a 12-bit ADC, the lowest number can represent 0, the highest number can represent 4095, and the resolution, when expressed in mechanical degrees, can be defined as (360 / M) / 4096, or generally: resolution = (360° / M) divided by 2 raised to the power of K (power(2, K)), where for a 12-bit ADC, K = 12.
[0150] When the inductive angle sensor of the present invention (N=9, M=6, ratio=1.5, range=±10°) is compared with the classic inductive angle sensor (N=18, M=9, ratio=2, range=±10°), the resolution of the sensor proposed by the present invention is only 1.5 times lower.
[0151] ii) Second factor: noise and signal strength
[0152] Inductive sensors with high periodicity (i.e., large N or M) have a significant drawback: as periodicity increases, the signal strength of the signal provided by the receiver coil weakens because the target leaf (or tooth) becomes smaller and is less efficiently excited, resulting in an increase in noise level (i.e., a decrease in signal-to-noise ratio SNR).
[0153] This is Figure 5 The image is shown in the middle. Figure 5 A graph showing the typical signal strength variation with periodicity is shown. It can be seen that the greater the periodicity, the smaller the signal strength. The signal strength of an inductive sensor depends largely on its periodicity (read: N and M) and size (e.g., radius). For a given size (e.g., radius), the signal strength decreases as the periodicity increases.
[0154] Figure 6An illustrative curve is shown, illustrating the variation of typical noise levels (in arbitrary units) with respect to the periodicity (e.g., the number of leaves) of the coupling element and receiver coil, which can be obtained by measurement or computer simulation, with the coupling element mounted at a predetermined distance from the receiver coil.
[0155] Noise is inversely proportional to signal strength. Therefore, the noise performance of a sensor can be improved by increasing the signal level. It should be noted that "noise expressed in electrical angles" is obtained as 1 / signal_strength(1 / signal_strength). To obtain "noise expressed in mechanical angles," the "noise expressed in electrical angles" needs to be divided by the periodicity.
[0156] Figure 6 The example is through, for example, Figure 1A The signal strength of the inductive angle sensor illustrated in the figure was obtained by computer simulation modeling. The inductive angle sensor has a target coil with a diameter of 5.0 cm, and the target coil is arranged at an air gap "g" 2.0 mm away from the printed circuit board 110.
[0157] When comparing the inductive angle sensor of the present invention with (N=9, M=6, ratio=1.5, range=±10°) with a classic inductive angle sensor with (N=18, M=9, ratio=2, range=±10°), the former typically has about 29% lower noise than the latter, because from Figure 6 It can be understood that the noise associated with N=9 is approximately 32, and the noise associated with M=6 is approximately 34. Therefore, for the sensor proposed by this invention, the total noise for (N=9 and M=6) is proportional to sqrt(32^2 + 34^2) ≈ 46.7; the noise associated with N=18 is approximately 51, and the noise associated with M=9 is approximately 32. Therefore, for the classical sensor with (N=18 and M=9), the total noise is proportional to sqrt(51^2 + 32^2) ≈ 60.2. Thus, the noise of the sensor proposed by this invention with N=9 and M=6 is approximately 29% lower than the noise of the classical sensor with the same angular range (N=18 and M=9). Although this is only an example for N=9 and M=6, the same or similar principles also apply to the sensors of this invention with periodicity other than N=9 and M=6.
[0158] iii) Third factor: crosstalk
[0159] Ideally, the first angle value (e.g., for the input shaft) is independent of the second angle value (e.g., for the output shaft), and the second angle value (e.g., for the input shaft) is independent of the first angle value (e.g., for the output shaft). However, in practice, to obtain independent measurements using a single printed circuit board, a shielding layer between the first and second sets of coils may be needed to avoid crosstalk. This means that such a printed circuit board 110 (see...) Figure 1C It needs to have at least six layers: two layers for the first set of receiver coils, two shielding layers, and two layers for the second set of receiver coils.
[0160] Even when excited by a perfect sine wave, an inductive target with periodicity N will generate an alternating magnetic field containing the fundamental frequency and harmonics of orders N, 2N, 3N, 4N, 5N, 6N, 7N, etc., due to spatial modulation (e.g., related to the periodicity and / or geometry of the receiver coil and / or the movable target). Surprisingly, the inductive angle sensor proposed in this invention, with an N / M ratio equal to 1.5, is particularly advantageous in terms of crosstalk.
[0161] In fact, the inventors were surprised to find that a two-phase coil system (where the two input signals have essentially the same amplitude but are phase-shifted by 90°) is sensitive to odd-order harmonics (i.e., harmonics of order N, 3N, 5N, 7N, 9N, etc.), but a three-phase coil system (where the three input signals have essentially the same amplitude but are phase-shifted by 120°) is sensitive to harmonics of order N, 5N, 7N, 11N, 13N, etc., but not sensitive to harmonics of order 3N, 9N, and other multiples of 3N.
[0162] When the second coil group (with periodicity M) emits a signal with a fundamental frequency, it is "treated" by the first coil group (with periodicity N = 1.5 * M) as a signal with a frequency 1.5 times the fundamental frequency, but the first coil group is not sensitive to this.
[0163] When the second coil group emits the second harmonic (2M), it is regarded as (3N) by the first coil group, but if the first coil group is a three-phase system, the first coil group is not sensitive to this frequency;
[0164] When the second coil group emits the third harmonic (3M), it is regarded as (4.5N) by the first coil group, but the first coil group is not sensitive to this frequency;
[0165] When the second coil group emits the fourth harmonic (4M), it is regarded as (6N) by the first coil group, but the first coil group is not sensitive to this frequency;
[0166] When the second coil group emits the fifth harmonic (5M), it is regarded as (7.5N) by the first coil group, but the first coil group is not sensitive to this frequency;
[0167] When the second coil group emits the sixth harmonic (6M), it is regarded as (9N) by the first coil group, but if the first coil group is a three-phase system, the first coil group is not sensitive to this frequency, and so on.
[0168] Therefore, in the inductive angle sensor of the present invention with N / M = 1.5, if the first coil group (with periodicity N) is a three-phase system, the first coil group will not experience crosstalk from the signal emitted by the second coil group (with periodicity M). In other words, the second coil group (with periodicity M) will not interfere with the signal of the first coil group (with periodicity N). In fact, simulations have shown that the crosstalk of the inductive angle sensor with N / M = 1.5 is negligible not only for three-phase systems but also for two-phase systems.
[0169] Following similar reasoning, it can be shown that the second coil group (with periodicity M) will also not suffer from crosstalk from signals emitted by the first coil group (with periodicity N). In fact,
[0170] When the first coil group (with periodicity N) emits a signal with a fundamental frequency, it is "considered" by the second coil group (with periodicity M = N / 1.5) as a signal with a frequency of 0.67 times the fundamental frequency, but the second coil group is not sensitive to this frequency;
[0171] When the first coil group emits a second harmonic (2N), it is regarded as (1.33M) by the second coil group, but the second coil group is not sensitive to this frequency;
[0172] When the first coil group emits the third harmonic (3N), it is regarded as (2M) by the second coil group, but the second coil group is not sensitive to this frequency;
[0173] When the first coil group emits the fourth harmonic (4N), it is regarded as (2.66M) by the second coil group, but the second coil group is not sensitive to this frequency;
[0174] When the first coil group emits the fifth harmonic (5N), it is regarded as (3.33M) by the second coil group, but the second coil group is not sensitive to this frequency;
[0175] When the first coil group emits the sixth harmonic (6N), it is regarded as (4M) by the second coil group, but the second coil group is not sensitive to this frequency, and so on.
[0176] Therefore, in the inductive angle sensor of the present invention with N / M = 1.5, regardless of whether the second coil group (with periodicity M) is implemented using a two-phase system or a three-phase system, the second coil group will not be subject to crosstalk from the signal emitted by the first coil group (with periodicity N). In other words, the first coil group (with periodicity N) will not interfere with the signal of the second coil group (with periodicity M).
[0177] Even if the first and second receiver coils are implemented on a four-layer printed circuit board without two shielding layers, the production of which is less complex than that of a six-layer PCB and therefore cheaper.
[0178] The independence of the first and second sets of coils was quantitatively investigated through simulation. A model without shielding was used, where N=9, M=6, and the ratio = 1.5; Tx coil diameter: 38mm; Rx coil outer diameter: 34mm; Rx coil inner diameter: 22mm; target outer diameter: 40mm; target inner diameter: 20mm; air gap between the first target and the first set of receiver coils: 2.0mm; air gap between the second target and the second set of receiver coils: 2.0mm; PCB thickness: 1.0mm; air gap between the first target and the second set of receiver coils: 3.0mm; air gap between the second target and the first set of receiver coils: 3.0mm (e.g., as...). Figure 1A As depicted in the text, assuming a PCB thickness of 1.0 mm.
[0179] For the inductive angle sensor of the present invention having N=9 and M=6, the following results were found: the first movable target (where N=9) generates a 10mV signal in the first receiver coil, the second movable target (where M=6) generates a 20mV signal in the second receiver coil, the first target (where N=9) generates a signal less than 10μV in the second set of coils (where M=6), and the second target (where M=6) generates a signal less than 10μV in the first set of coils (where N=6), such that the differential angle error is less than 0.01°.
[0180] These simulations were also performed on a model of a classic inductive angle sensor with N=18 and M=9, a ratio of 2, identical dimensions (d=5cm, g=3mm), and no shielding. In this case, the second target (where M=9) generates a 0.2mV signal in the first set of coils (where N=18), resulting in a differential angle error greater than 0.1°.
[0181] In conclusion, it can be shown that the inductive angle sensor with a first periodicity N and a second periodicity M (where N / M = 1.5) as described above is an effective alternative to the classic inductive angle sensor with a first periodicity N and a second periodicity M (where N / M is an integer value).
[0182] When considering a six-layer PCB with two shielding layers, the proposed solution (where N / M = 1.5) offers similar range, slightly lower resolution (typically a factor of 1.5), and slightly lower noise (typically a factor of 1.29) due to its smaller periodicity value, and exhibits no significant crosstalk. Overall, this translates to slightly higher accuracy compared to a classic solution implemented in a six-layer PCB with the same range and dimensions, also containing two shielding layers.
[0183] When considering a four-layer PCB without two shielding layers, the proposed solution (where N / M = 1.5) offers similar range, slightly lower resolution (typically a factor of 1.5), and slightly lower noise (typically a factor of 2.5) due to its smaller periodicity value, but with significantly lower crosstalk. Overall, this translates to much higher accuracy compared to a classic solution implemented in a four-layer PCB with the same range and size but without two shielding layers.
[0184] Although the description mentioned above is primarily for inductive angle sensors with N=9 and M=6, the same reasoning applies to situations where N / M=1.5 (e.g., as...). Figure 4B Other inductive angle sensors (shown in the diagram for the values of N and M).
[0185] Although an example with a 12-bit ADC was used, the invention is not limited thereto, and other ADCs (e.g., 14-bit or 16-bit ADCs) can also be used.
[0186] Figure label:
[0187] 100 Torque sensor (including: angle sensor system and torsion bar)
[0188] 101 Angle Sensor System (including: multiple coils, two targets, and electronic components)
[0189] 110,310 Printed Circuit Board (PCB)
[0190] 320 sensor devices
[0191] 321 Oscillator Circuit
[0192] 322 Amplifier
[0193] 323 Demodulator or rectifier and filter
[0194] 324 Non-volatile memory (NVMEM) (e.g., flash memory)
[0195] 325 controller
[0196] 326 DSP
[0197] 327 ADC
[0198] 128,328 Integrated semiconductor devices (ICs or chips)
[0199] 131,231,331 First movable target
[0200] 132,232,332 Second movable target
[0201] 141 Torsion bar
[0202] 142 Input shaft section
[0203] 143 Output Shaft Section
[0204] g air gap
[0205] N First periodicity
[0206] M Second periodicity
[0207] TX transmitter coil
[0208] RX1a, RX1b, RX1c First group of receiver coils
[0209] RX2a, RX2b, RX2c Second group of receiver coils
Claims
1. An inductive angle sensor, comprising: At least one transmitter coil (TX) is used to generate an alternating magnetic field; At least one excitation circuit is provided for generating an alternating signal to energize the at least one transmitter coil. The first group of receiver coils (RX1a, RX1b, RX1c) each have a geometry with a first periodicity (N); The second set of receiver coils (Rx2a, RX2b, RX2c) each have a geometry with a second periodicity (M) that is smaller than the first periodicity (N). An evaluation circuit is used to evaluate the signals obtained from the first set of receiver coils and the second set of receiver coils; A first movable coupling element is used to provide inductive coupling between the at least one transmitter coil (TX) and the first set of receiver coils (RX1a, RX1b, RX1c), the first movable coupling element having a periodic geometry with the first periodicity (N); A second movable coupling element is used to provide inductive coupling between the at least one transmitter coil and the second set of receiver coils (Rx2a, RX2b, RX2c), the second movable coupling element having a periodic geometry with the second periodicity (M); Wherein, the ratio of the first periodicity (N) to the second periodicity (M) is equal to 1.5; Its features The first periodicity (N) equals 6, and the second periodicity (M) equals 4; or The first periodicity (N) equals 9, and the second periodicity (M) equals 6; or The first periodicity (N) equals 12, and the second periodicity (M) equals 8; or The first periodicity (N) is equal to 15, and the second periodicity (M) is equal to 10; or The first periodicity (N) is equal to 18, and the second periodicity (M) is equal to 12.
2. The inductive angle sensor according to claim 1, in, The evaluation circuit is configured to determine a first angle value (α1) based on the signal obtained from the first set of receiver coils and the first periodicity (N), and to determine a second angle value (α2) based on the signal obtained from the second set of receiver coils and the second periodicity (M), and to determine the difference between the first angle value (α1) and the second angle value (α2).
3. The inductive angle sensor according to any one of the preceding claims, in, The first set of receiver coils has a two-phase loop structure, and the second set of receiver coils also has a two-phase loop structure; or Wherein, the first set of receiver coils has a two-phase loop structure, and wherein the second set of receiver coils has a three-phase loop structure; or Wherein, the first set of receiver coils has a three-phase loop structure, and wherein the second set of receiver coils has a two-phase loop structure; or The first set of receiver coils has a three-phase loop structure, and the second set of receiver coils also has a three-phase loop structure.
4. The inductive angle sensor according to any one of claims 1 or 2, in, At least one of the first group of receiver coils and the second group of receiver coils has a three-phase loop structure; Furthermore, the at least one transmitter coil, the first set of receiver coils, and the second set of receiver coils are implemented on a single multilayer printed circuit board.
5. The inductive angle sensor according to claim 4, in, The printed circuit board is a four-layer printed circuit board.
6. An inductive torque sensor, comprising: Torsion bar; The inductive angle sensor according to any one of the preceding claims; The first movable coupling element and the second movable coupling element are connected to the torsion bar.
7. A printed circuit board, comprising: At least one transmitter coil (TX) is used to generate an alternating magnetic field; The first group of receiver coils (RX1a, RX1b, RX1c) each have a geometry with a first periodicity (N); The second set of receiver coils (Rx2a, RX2b, RX2c) each have a geometry with a second periodicity (M) that is smaller than the first periodicity (N). Wherein, the ratio of the first periodicity (N) to the second periodicity (M) is equal to 1.5; The printed circuit board consists of only four layers. Its features The first periodicity (N) equals 6, and the second periodicity (M) equals 4; or The first periodicity (N) equals 9, and the second periodicity (M) equals 6; or The first periodicity (N) equals 12, and the second periodicity (M) equals 8; or The first periodicity (N) is equal to 15, and the second periodicity (M) is equal to 10; or The first periodicity (N) is equal to 18, and the second periodicity (M) is equal to 12.
8. The printed circuit board according to claim 7, further comprising: At least one excitation circuit is provided for generating an alternating signal to energize the at least one transmitter coil. An evaluation circuit is used to evaluate the signals obtained from the first set of receiver coils and the second set of receiver coils.
9. The printed circuit board according to claim 8, in, The at least one excitation circuit and the evaluation circuit are implemented in a single integrated circuit device, which is mounted on the printed circuit board.
Citation Information
Patent Citations
Inductive position sensor
EP3885711A1
Inductive torque sensor
US20100319467A1
Inductive sensor
CN101019006A
Absolute rotary encoder and micrometer
US20060250128A1