Inductive angle sensor

Abstract

The present invention provides an inductive angle sensor comprising a coaxially arranged rotor conductive target and stator coil. The stator coil comprises an excitation coil and two receiving coils offset 90° around the axis. Each receiving coil is wound from a single wire and comprises a non-overlapping multipole pair of receiving coils and a monopole pair of receiving coils. The multipole pair of receiving coils has multiple first magnetic flux regions. Under the action of the excitation coil, the current loops formed by two adjacent first magnetic flux regions have opposite polarities. The monopole pair of receiving coils has two second magnetic flux regions with opposite polarities. The rotor conductive target has multiple first and second blocking regions. When the rotor conductive target rotates about its axis, the magnetic flux area of the first magnetic flux region covered by the first blocking region and the magnetic flux area of the second magnetic flux region covered by the second blocking region vary in a sinusoidal or cosine function with the angle of rotation of the rotor conductive target. The present invention enables high-resolution absolute angle measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to an inductive angle sensor. Background Art

[0002] Reliable and low-cost angle sensors with sufficient accuracy are in great demand in industrial, automotive, and robotics applications. Automotive applications include throttle position sensing, steering wheel sensing, and pedal position sensing. Angle measurement is also a common measurement method in robotics, including wheel alignment and joint angle measurement. Inductive angle sensors are considered an attractive option due to their high reliability, high resolution, and insensitivity to external environments, resulting from their unique structure. PCB-based inductive angle sensors offer practical advantages such as low cost, high compactness, and controllable coil layout.

[0003] Traditional inductive absolute angle sensors consist of an excitation coil and two receiving coils. These two receiving coils are coaxially arranged, staggered 90° apart, and each has a single pole pair. One receiving coil generates a sine signal, while the other generates a cosine signal. This sensor structure is capable of measuring the absolute angular position of a target. By increasing the number of receiving coil pole pairs within a full 360° circle and appropriately modifying the target rotor geometry, the mechanical angle accuracy and resolution of each rotation can be improved by generating higher-frequency sine and cosine signals than those generated by a single-pole pair receiving coil. However, using this structure makes it impossible to obtain the absolute angle information of the target being measured.

[0004] In order to both determine the absolute angle of the target rotor being measured and achieve high-resolution measurement, the Chinese invention patent with publication number CN113984093A introduces a position sensor, which includes at least one transmitting coil, an absolute position receiving coil pair, a high-resolution position receiving coil pair and a conductive moving target, wherein the absolute position receiving coil pair and the high-resolution position receiving coil pair together define a measurement area of the inductive angle sensor, and the mobile target can move within the measurement area, wherein the absolute position coil pair has a first sine receiving coil and a first cosine receiving coil, both of which have one period over the measurement area of the inductive angle sensor; and the high-resolution position receiving coil pair has a second sine receiving coil and a second cosine receiving coil, both of which have at least two periods over the measurement area of the inductive angle sensor; the absolute position receiving coil pair and the high-resolution position receiving coil pair are arranged in the same area of the printed circuit board of the inductive angle sensor. The sensor described in this patent places the absolute position receiving coil and the high-resolution position receiving coil on the same PCB substrate to achieve high-resolution absolute angle measurement of the sensor. However, the PCB board involved in this patent has more receiving coils, which requires a large number of vias with more parasitic capacitance and redundant loop area that affects signal quality. There are also many output interfaces (at least 8) and two signal conditioning circuits must be used to process the sensor output signal. This undoubtedly greatly increases the cost of the sensor system and reduces the efficiency of signal processing. Summary of the Invention

[0005] The object of the present invention is to provide an inductive angle sensor that, on the one hand, achieves high-resolution absolute angle measurement, and on the other hand, can save space and the number of layers of a PCB board, reduce parasitic capacitance caused by vias, and reduce the output interface required for the receiving coil, thereby reducing the production cost of the inductive angle sensor and improving signal processing efficiency.

[0006] To achieve the above object, the present invention provides an inductive angle sensor comprising a coaxially arranged rotor conductive target and a stator coil, wherein the stator coil comprises an excitation coil and two receiving coils, wherein the two receiving coils are arranged 90° apart around the axis, wherein:

[0007] Each receiving coil is wound with a single wire and comprises a multi-pole pair of receiving coils and a monopole pair of receiving coils that do not overlap each other. The multi-pole pair of receiving coils has a plurality of first magnetic flux regions, and the plurality of first magnetic flux regions are configured such that, under the action of the excitation coil, the polarity of the current loop formed by two adjacent first magnetic flux regions is opposite, and the monopole pair of receiving coils has two second magnetic flux regions with opposite polarity.

[0008] The rotor conductive target has a plurality of first blocking areas spaced apart from each other and adapted to the shape of the first magnetic flux area, and a second blocking area adapted to the shape of the second magnetic flux area. When the rotor conductive target rotates around the axis, the magnetic flux area of the first magnetic flux area covered by the first blocking areas and the magnetic flux area of the second magnetic flux area covered by the second blocking areas vary in a sinusoidal or cosine function with the rotation angle of the rotor conductive target.

[0009] Optionally, the number of the first blocking areas of the rotor conductive target is half the number of the first magnetic flux areas of the multi-pole pair receiving coils.

[0010] Optionally, when the rotor conductive target rotates by a predetermined angle, each of the first blocking areas can just cover all first magnetic flux areas with the same polarity in the multi-pole pair receiving coils.

[0011] Optionally, the second blocking zone of the rotor conductive target is configured so that when each of the first blocking zones can just cover all first magnetic flux zones with the same polarity in the multi-pole pair receiving coils, the second blocking zone can just cover second magnetic flux zones with the same polarity.

[0012] Optionally, there is a central area between the two second magnetic flux areas of the monopole pair receiving coils, and the center of the rotor conductive target also has a central blocking area capable of covering at least a portion of the central area.

[0013] Optionally, the excitation coil and the two receiving coils each have a pair of output interfaces for connecting to a signal processing unit built into or externally connected to the inductive angle sensor, and the signal processing unit is used to provide signals to the excitation coil and / or to process signals from the receiving coils.

[0014] Optionally, there are two rotor conductive targets, which are respectively located on opposite sides of the stator coil, and the two rotor conductive targets are connected by a rotating shaft to keep a constant distance between the two rotor conductive targets.

[0015] Optionally, the inductive angle sensor is integrated into a PCB board.

[0016] Optionally, the PCB board has four layers, wherein the two receiving coils are respectively located in the same two layers of the PCB board.

[0017] Optionally, the multi-pole pair receiving coil is connected to the monopole pair receiving coil via a connecting portion, and the connecting portion is arranged in a direction perpendicular to the PCB board.

[0018] The present invention provides an inductive angle sensor having at least one of the following beneficial effects:

[0019] 1) By designing the receiving coil as a structure consisting of a single wire wound with non-overlapping multi-pole pair receiving coils and a monopole pair receiving coil, and by designing a rotor conductive target of a specific shape, the monopole pair receiving coil can achieve absolute angle measurement, and the multipole pair receiving coil can ensure the resolution of angle measurement, thereby achieving high-resolution absolute angle measurement;

[0020] 2) Since only two receiving coils are required, the area and number of layers of the PCB board can be saved, the parasitic capacitance caused by vias can be reduced, and the number of output interfaces required for the receiving coils can be reduced, thereby reducing the production cost of the inductive angle sensor and improving signal processing efficiency;

[0021] 3) This technology solves the technical problems of existing high-resolution inductive angle sensors, such as their inability to perform absolute angle measurement and their low measurement accuracy and resolution. It also addresses the problems of some high-resolution absolute angle sensors, such as complex output interfaces and multiple PCB substrate layers, which affect production costs and signal processing efficiency.

[0022] 4) Each receiving coil only needs to be connected to the signal processing unit through a pair of output interfaces (input port and output port), and each inductive angle sensor only needs one set of signal processing units (position sensor dedicated chip) to output angle information, which greatly reduces the production cost of the inductive angle sensor and improves the signal processing efficiency of the inductive angle sensor;

[0023] 5) By introducing two identical rotor conductive targets and their corresponding layout, the problem that the output signal amplitude of the existing inductive sensor is greatly affected by the change in the rotor-stator spacing is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0025] Figure 1 A schematic diagram of an inductive angle sensor provided in Example 1 of the present invention;

[0026] Figure 2 A schematic plan view of a receiving coil provided in the first embodiment of the present invention;

[0027] Figure 3 A three-dimensional schematic diagram of a receiving coil provided in Example 1 of the present invention;

[0028] Figure 4 A magnetic flux distribution diagram of a multi-pole pair receiving coil provided in Example 1 of the present invention;

[0029] Figure 5 A schematic diagram of a rotor conductive target provided in Embodiment 1 of the present invention;

[0030] Figure 6 A schematic diagram of a multi-pole pair receiving coil and a rotor conductive target provided in the first embodiment of the present invention;

[0031] Figure 7 A schematic plan view of a receiving coil provided in the second embodiment of the present invention;

[0032] Figure 8 A schematic diagram of a rotor conductive target provided in a third embodiment of the present invention;

[0033] Figure 9 This is a schematic diagram of a rotor conductive target provided in embodiment 4 of the present invention.

[0034] In the attached figure:

[0035] 1-PCB board; 2-rotor conductive target; 3-excitation coil; 4-receiving coil; 5-signal processing unit; 6-via; 7-output interface;

[0036] 21-first blocking zone; 22-first blocking zone; 23-central blocking zone; 41-multi-pole pair receiving coil; 42-monopole pair receiving coil; 43-connecting part; 410-first magnetic flux zone; 420-second magnetic flux zone; P1, P2, P3...P10-first magnetic flux zone. DETAILED DESCRIPTION

[0037] As described in the background, a conventional inductive absolute angle sensor consists of an excitation coil and two receiving coils, coaxially arranged and staggered 90° apart. Each coil has a single pole pair, with one receiving coil generating a sine signal and the other generating a cosine signal. This sensor structure can measure the absolute angular position of a target. By increasing the number of receiving coil pole pairs within a full 360° circle and appropriately modifying the target rotor geometry, the mechanical angle accuracy and resolution of each rotation can be improved by generating higher-frequency sine and cosine signals than those generated by a single-pole-pair receiving coil. However, using this structure will prevent the acquisition of the target's absolute angle information.

[0038] The present invention aims to solve the technical problems that high-resolution inductive angle sensors cannot perform absolute angle measurement and that absolute angle sensors have low measurement accuracy and resolution. At the same time, it aims to solve the problems of some existing high-resolution absolute angle sensors, such as complex output interfaces and multiple PCB substrate layers, which affect production costs and signal processing efficiency.

[0039] Based on this, the present invention provides an inductive angle sensor, comprising a coaxially arranged rotor conductive target and a stator coil, wherein the stator coil comprises an excitation coil and two receiving coils, and the two receiving coils are arranged 90° apart around the axis, wherein:

[0040] Each receiving coil is wound with a single wire and comprises a multi-pole pair of receiving coils and a monopole pair of receiving coils that do not overlap each other. The multi-pole pair of receiving coils has a plurality of first magnetic flux regions, and the plurality of first magnetic flux regions are configured such that, under the action of the excitation coil, the polarity of the current loop formed by two adjacent first magnetic flux regions is opposite, and the monopole pair of receiving coils has two second magnetic flux regions with opposite polarity.

[0041] The rotor conductive target has a plurality of first blocking areas spaced apart from each other and adapted to the shape of the first magnetic flux area, and a second blocking area adapted to the shape of the second magnetic flux area. When the rotor conductive target rotates around the axis, the magnetic flux area of the first magnetic flux area covered by the first blocking areas and the magnetic flux area of the second magnetic flux area covered by the second blocking areas vary in a sinusoidal or cosine function with the rotation angle of the rotor conductive target.

[0042] By designing the receiving coil as a single-wire structure with non-overlapping multi-pole and monopole pairs, and by designing a rotor conductive target with a specific shape, the monopole pair can achieve absolute angle measurement, while the multipole pair can ensure angle measurement resolution, thus achieving high-resolution absolute angle measurement. Since only two receiving coils are required, this saves space and the number of layers on the PCB, reduces parasitic capacitance caused by vias, and reduces the number of output interfaces required for the receiving coils. This reduces the manufacturing cost of the inductive angle sensor and improves signal processing efficiency.

[0043] To make the objects, advantages, and features of the present invention more clearly apparent, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale. They are only used to conveniently and clearly assist in illustrating the purposes of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structure. In particular, different drawings may need to illustrate different focuses and sometimes use different scales.

[0044] The singular terms "one", "an" and "the" used in the present invention may include plural objects, unless the content clearly indicates otherwise. The term "or" used in the present invention is generally used to include the meaning of "and / or", unless the content clearly indicates otherwise. The term "several" used in the present invention is generally used to include the meaning of "at least one", unless the content clearly indicates otherwise. The term "at least two" used in the present invention is generally used to include the meaning of "two or more", unless the content clearly indicates otherwise. In addition, the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features.

[0045] Example 1

[0046] Please refer to Figures 1-6 This embodiment provides an inductive angle sensor, including a coaxially arranged rotor conductive target 2 and a stator coil, wherein the stator coil includes an excitation coil 3 and two receiving coils 4, and the two receiving coils 4 are staggered 90 degrees around the axis, wherein:

[0047] Each receiving coil 4 is wound from a single wire and includes a multi-pole pair receiving coil 41 and a monopole pair receiving coil 42 that do not overlap each other. The multi-pole pair receiving coil 41 has a plurality of first magnetic flux regions 410, and the plurality of first magnetic flux regions 410 are configured such that, under the action of the excitation coil 3, the current loops formed by two adjacent first magnetic flux regions 410 have opposite polarities. The monopole pair receiving coil 42 has two second magnetic flux regions 420 with opposite polarities.

[0048] The rotor conductive target 2 has a plurality of first blocking areas 21 spaced apart from each other and adapted to the shape of the first magnetic flux area 410, and a second blocking area 22 adapted to the shape of the second magnetic flux area 420. When the rotor conductive target 2 rotates around the axis, the magnetic flux area of the first magnetic flux area 410 covered by the first blocking area 21 and the magnetic flux area of the second magnetic flux area 420 covered by the second blocking area 22 vary in a sinusoidal or cosine function with the rotation angle of the rotor conductive target 2.

[0049] The principle of the inductive angle sensor provided in this embodiment is first described below.

[0050] The receiving coil 4 does not generate an induced voltage in the alternating magnetic field generated by the excitation coil 3 due to its special structure. When a rotor conductive target 2 is added above the receiving coil 4, the rotor conductive target 2 will generate an alternating magnetic field B generated by the excitation coil 3. S Eddy currents are generated in the magnetic field, which in turn generate a new alternating magnetic field B. R , the alternating magnetic field B R This will cause the receiving coil 4 to generate an induced voltage. Therefore, as long as the receiving coil 4 is wound into a specific shape and matched with the rotor conductive target 2 of a corresponding shape, the area of the receiving coil 4 covered by the rotor conductive target 2 (i.e., the magnetic flux area of the magnetic field) can be made to change in a sinusoidal or cosine function with the angle of rotation of the conductive target, thereby making the induced voltage follow a sinusoidal or cosine function relationship with the angle of rotation of the rotor conductive target 2.

[0051] For details, please combine Figure 4 When the central axis of the receiving coil 4 coincides with the central axis of the exciting coil 3, the multi-pole pair receiving coil 41 generates 10 first magnetic flux zones 410 P1-P10 in the radial uniform alternating magnetic field generated by the exciting coil 3. Since the areas of the 10 first magnetic flux zones 410 P1-P10 are the same, and the polarities (current directions) of the current loops formed by two adjacent first magnetic flux zones 410 under the action of the exciting coil 3 are opposite, Figure 4 As indicated by the arrows in the figure, such a multi-pole pair receiving coil 41 will not generate an induced electromotive force only under the action of the radial uniform alternating magnetic field generated by the excitation coil 3. If a current loop in the multi-pole pair receiving coil 41 is called a pole, the multi-pole pair receiving coil 41 in this embodiment has 10 poles, and each pair of opposite poles is called a pole pair. Therefore, the multi-pole pair receiving coil 41 in this embodiment has 5 pole pairs and can be called a five-pole pair receiving coil. Figure 6 As shown, if the shape of each first blocking area 21 of the rotor conductive target 2 is made to be similar to the size of each first magnetic flux area 410 of the multi-pole pair receiving coil 41 (the size here can be understood as the size along the circumferential direction), and all the first blocking areas 21 together can cover half of the first magnetic flux areas 410 of the multi-pole pair receiving coil 41, then in the current loop formed by the multi-pole pair receiving coil 41, the magnetic flux and the time change rate of the magnetic flux of the first magnetic flux area 410 covered by the rotor conductive target 2 and the first magnetic flux area 410 not covered by the rotor conductive target 2 are inconsistent, so the induced electromotive force generated by them will also be inconsistent. Therefore, the induced electromotive force generated by the current loops with opposite polarities will not cancel each other, and the multi-pole pair receiving coil 41 will generate an induced electromotive force.

[0052] In this embodiment, the shape function of the multi-pole pair receiving coil 41 is set to:

[0053]

[0054] Where C1 and C2 are constants, p is the number of pole pairs of the multi-pole pair receiving coil 41, and θ is the rotation angle of the rotor conductive target 2. When the rotor conductive target 2 rotates, the magnetic flux area of the first magnetic flux region 410 of the multi-pole pair receiving coil 4 covered by the first blocking region 21 varies in a sinusoidal or cosine function with the rotation angle of the rotor conductive target 2. The variation function is Φ = A cos(5θ), where A is a constant and θ is the rotation angle of the rotor.

[0055] The two second magnetic flux regions 420 of the monopole pair receiving coil 42 are similar, and their magnetic flux areas vary in a sinusoidal or cosine function as the angle of rotation of the rotor conductive target 2 .

[0056] Based on the above theory, this embodiment connects a multi-pole pair receiving coil 41 and a monopole pair receiving coil 42, which do not overlap in space, and winds them together with a single wire on a PCB board 1 to form a receiving coil 4. When such a receiving coil 4 works in conjunction with the rotor conductive target 2, since it is wound with a single wire, the magnetic flux areas of the multi-pole pair receiving coil 41 and the monopole pair receiving coil 42 will also be superimposed. Assuming that the rotation angle θ of the rotor conductive target 2 is a function of time t, that is, θ = α(t), then Figure 1 The total magnetic flux areas of the two receiving coils 4, each including a five-pole pair receiving coil 41 and a single-pole pair receiving coil 42, are as follows:

[0057] S1=A1sin[5α(t)]+A2sin[a(t)]

[0058] S2=A1cos[5α(t)]+A2cos[α(t)]

[0059] Where A1 and A2 are constants. When a multi-pole receiving coil 41 with other numbers of pole pairs is used, for example, 6 pole pairs, 5 in the above formula should be replaced by 6.

[0060] When the excitation signal sin(ω exc t), the ideal output signal of the inductive angle sensor is:

[0061]

[0062]

[0063] Among them B Ris the magnitude of the alternating magnetic field, k is a constant greater than 0 and less than 1, k is related to the ratio of the total area of the magnetic flux zone of the monopole pair receiving coil 42 to the multipole pair receiving coil 41, and the excitation signal frequency is ω exc t, A coil is the maximum amplitude of the output voltage of the multi-pole pair receiving coil 41, and the output signal of the receiving coil 4 after demodulation by the signal processing unit 5 is:

[0064] V o_sin (t) = A coil ·sin[5α(t)]+A coil ·k·sin[α(t)]

[0065] V o_cos (t) = A coil ·cos[5α(t)]+A coil k coS[α(t)]

[0066] Dividing the two equations, we can get:

[0067]

[0068]

[0069] Therefore, according to V o_sin (t) and V o_cos The angle θ can be calculated from the measured value of (t).

[0070] It should be understood that the rotor conductive target 2 generates a periodic signal when it rotates one circle, and the V corresponding to each angle in one cycle is o_sin (t) or V o_cos (t) value is different, so according to the sensor output V o_sin (t) and V o_cos The absolute angle value of the rotor conductive target 2 within the range of 0-360° can be calculated based on the value of (t).

[0071] There are two most important indicators in the output signal of the inductive angle sensor, amplitude and offset (DC offset). In the actual application of the angle sensor, some non-ideal factors such as changes in the rotor-stator spacing, rotor-stator eccentricity, rotor tilt, etc., these non-ideal factors will cause changes in amplitude or amplitude mismatch and offset changes, greatly reducing the precision and accuracy of the angle value calculated by the output signal. Amplitude mismatch refers to the fact that the signal amplitudes output by the output channels of the two receiving coils 4 are not equal, which is mainly caused by the two receiving coils 4 not being exactly the same; coil offset refers to a non-zero DC value in the output signal of the receiving coil 4 (theoretically, this DC value should be equal to 0), which is mainly caused by the fact that each pole pair inside the receiving coil 4 is not strictly the same; the above-mentioned non-ideal factors such as changes in the rotor-stator spacing, rotor-stator eccentricity, rotor tilt, etc. will also cause varying degrees of amplitude mismatch and offset; at the same time, inductive coupling and capacitive coupling between different coils are also important causes of amplitude mismatch and offset. If the existence of amplitude mismatch and offset is added, V o_sin (t) or V o_cos The formula for (t) will be rewritten as:

[0072] V o_sin (t) = A coil1 ·sin[5α(t)]+A coil1 k1 sin[α(t)]+offset1

[0073] V o_cos (t) = A coil1 ·cos[5α(t)]+A coil2 k2 cos[α(t)]+offset2

[0074] Among them A coil1 and A coil2 are the maximum amplitudes of the output voltages of the two five-pole pairs of receiving coils 41; k1 and k2 are constants related to the ratio of the total magnetic flux area of the monopole pair of receiving coils 42 to the multipole pair of receiving coils 41; offset1 and offset2 are the offset values caused by the two receiving coils 4, respectively. As can be seen from the above formula, the smaller the amplitude mismatch and offset, the more accurate the angle value calculated by the inductive angle sensor output signal. Furthermore, a larger output signal amplitude also improves the performance of the inductive angle sensor.

[0075] In this embodiment, there are two receiving coils 4, each receiving coil 4 is composed of a multi-pole pair receiving coil 41 and a monopole pair receiving coil 42 connected in series, and its plan view is as follows: Figure 2As shown, in order to prevent the receiving coil 4 from generating an induced electromotive force only under the action of the radial uniform alternating magnetic field generated by the excitation coil 3, the two first magnetic flux regions 410 corresponding to each pole pair are the same in size and shape, and the two second magnetic flux regions 420 of the monopole pair receiving coil 42 are the same in size and shape.

[0076] In this embodiment, the number of pole pairs of the multi-pole pair receiving coil 41 can determine the resolution of the inductive angle sensor. The multi-pole pair receiving coil 41 can be understood as a high-resolution angle receiving coil, that is, the more pole pairs the multi-pole pair receiving coil 41 has, the higher the resolution of the inductive angle sensor. The monopole pair receiving coil 42 is used to measure absolute angle information. The monopole pair receiving coil 42 can be understood as an absolute angle receiving coil. Since the multi-pole pair receiving coil 41 and the monopole pair receiving coil 42 are wound with a single wire, the receiving coil 4 has the structure of a high-resolution angle receiving coil and an absolute angle receiving coil, thereby enabling high-resolution absolute angle measurement.

[0077] It should be noted that when the receiving coil 4 has both a multi-pole pair receiving coil 41 and a single-pole pair receiving coil 42, the shape of the rotor conductive target 2 needs to simultaneously satisfy the requirements that the two receiving coils can generate sine and cosine signals, so that when the rotor conductive target 2 rotates, the magnetic flux areas of the first magnetic flux zone 410 and the second magnetic flux zone 420 of the receiving coil 4 covered by the first blocking zone 21 and the second blocking zone 22 change in a sine or cosine function as the angle of rotation of the rotor conductive target 2 changes.

[0078] In this embodiment, the number of first blocking zones of the rotor conductive target is half the number of first magnetic flux zones of the multi-pole pair receiving coils. When the rotor conductive target 2 rotates around its axis by a predetermined angle, all first blocking zones 21 can precisely cover all first magnetic flux zones 410 of the same polarity in the multi-pole pair receiving coils 41, that is, they can cover half of the first magnetic flux zones 410 of the multi-pole pair receiving coils 41. Simultaneously, the second blocking zones 22 can precisely cover the second magnetic flux zones 420 of the same polarity as the first magnetic flux zones in the monopole pair receiving coils 42.

[0079] Preferably, the plurality of first blocking areas 21 of the rotor conductive target 2 have the same shape and / or spacing. Figure 5-Figure 6The rotor conductive target 2 covers multiple first barrier zones 21 of the multi-pole pair receiving coils 41, which are evenly distributed and have the same shape. The rotor conductive target 2 also includes a second barrier zone 22 that covers one of the second magnetic flux zones 420 of the monopole pair receiving coils 42. For example, in this embodiment, the multi-pole pair receiving coils 41 have ten first magnetic flux zones 410, and the monopole pair receiving coils 42 have two second magnetic flux zones 420. Thus, the rotor conductive target 2 has a total of five first barrier zones 21 and one second barrier zone 22. The five first barrier zones 21 have the same shape and are used to cover half of the first magnetic flux zones 410 of the multi-pole pair receiving coils 41. The remaining second barrier zone 22 is used to cover half of the magnetic flux zones 420 of the monopole pair receiving coils 42.

[0080] In this embodiment, there is no limitation on the specific shape of the blocking area, as long as it can cover the corresponding first magnetic flux area 410 of the multi-pole pair receiving coil 41 and the magnetic flux area 420 of the monopole pair receiving coil 42 .

[0081] In this embodiment, the inductive angle sensor is integrated into the PCB board 1 .

[0082] Preferably, since there are only two receiving coils 4, the two receiving coils 4 can occupy the same two layers on the PCB board 1, and the excitation coil 3 occupies one to two layers, so only four layers of PCB boards are needed at most to realize the layout of the receiving coil 4 and the excitation coil 3. Such a design can greatly reduce the number of vias, thereby greatly reducing parasitic capacitance and improving the efficiency of signal processing.

[0083] In this embodiment, combined with Figure 3 Taking the multipole pair receiving coil 41 as a five-pole pair as an example, each five-pole pair receiving coil has a total of 25 vias 6. The more pole pairs the multipole pair receiving coil 41 has, the more vias 6 there are. By designing the vias 6, the multipole pair receiving coil and the monopole pair receiving coil can be wound with a single wire without overlapping each other in space. Of course, this application does not impose any restrictions on the number of vias 6, which can be adjusted according to the number of pole pairs. Of course, in addition to Figure 3 In addition to the illustrated winding method, the receiving coil 4 can also be wound on the PCB board 1 in other ways, and this application does not limit this.

[0084] In this embodiment, the excitation coil 3 and the two receiving coils 4 each have a pair of output interfaces 7 for connecting to a signal processing unit 5 internal to or external to the inductive angle sensor. The signal processing unit 5 is used to provide signals to the excitation coil 3 and / or process the signals from the receiving coils 4. Each receiving coil 4 only needs to be connected to the signal processing unit 5 via a pair of output interfaces 7 (input port and output port), and each inductive angle sensor only needs one set of signal processing units 5 (dedicated position sensor chip) to output angle information. This significantly reduces the manufacturing cost of the inductive angle sensor and improves the signal processing efficiency of the inductive angle sensor.

[0085] In this embodiment, the two receiving coils 4 are offset 90° around the axis. This allows one receiving coil 4 to output a sine signal, while the other outputs a cosine signal, after signal processing by the signal processing unit 5. This allows for angle measurement. Furthermore, because each receiving coil 4 is composed of a multipole pair of receiving coils 41 and a monopole pair of receiving coils 42 connected in series, the signal output by each receiving coil 4 is a superimposed signal of the multipole pair of receiving coils 41 and the monopole pair of receiving coils 42. This means that the output signal of each receiving coil 4 is in the form of a sine + sine signal or a cosine + cosine signal.

[0086] Please continue to refer to Figure 1-Figure 3 The multi-pole pair receiving coil 41 is connected to the monopole pair receiving coil 42 via a connecting portion 43, which is arranged perpendicular to the PCB 1. As previously mentioned, since the receiving coil 4 is wound from a single wire, the magnetic flux areas of the multi-pole pair receiving coil 41 and the monopole pair receiving coil 42 are superimposed. Furthermore, the connecting portion 43 is fabricated in a perpendicular direction on different PCB layers, and its cross-section is parallel to the alternating magnetic field. Therefore, no magnetic flux area exists and is not required for angle calculation.

[0087] In this embodiment, the rotor conductive target 2 is made of metal. Preferably, the rotor conductive target 2 is made of copper metal, which is cheap and easy to manufacture.

[0088] Example 2

[0089] Please refer to Figure 7 , Figure 7A planar schematic diagram of a receiving coil provided in Example 2 of the present invention. Example 2 differs from Example 1 in that, in Example 2, the length of the connecting portion 43 is increased, which is equivalent to increasing the spacing between the multi-pole pair receiving coil 41 and the monopole pair receiving coil 42. This reduces the interference of the internal induced current generated by the receiving coil 4 on the magnetic field and reduces the parasitic capacitance coupling between the two different pole pairs of the receiving coil 4 (the capacitance between the metal plates is inversely proportional to the spacing between them), thereby reducing the DC offset of the receiving coil 4 and improving the performance of the inductive angle sensor.

[0090] Furthermore, since the length of the connecting portion 43 can be increased while reducing the area of the first magnetic flux zone 410 of the multipole pair receiving coil 41, the ratio of the total area of the magnetic flux zones of the monopole pair receiving coil 42 to the multipole pair receiving coil 41 is increased, thereby making the absolute measurement information of the angle more accurate.

[0091] Example 3

[0092] Please refer to Figure 8 , Figure 8 A schematic diagram of a rotor conductive target provided in Example 3 of the present invention. The difference between Example 3 and Example 1 is that, with respect to the central area between the two magnetic flux areas 420 of the monopole pair receiving coil 42, in Example 3, a central blocking area 23 covering at least a portion of the central area is formed at the center of the rotor conductive target 2, which is equivalent to adding a circular central blocking area 23 at the center of the rotor conductive target 2. The central blocking area 23 can fully utilize the magnetic field in the central part of the receiving coil 4 to generate eddy currents, thereby increasing the size of the eddy current magnetic field. Compared with the structure of Example 1, the signal amplitude can be effectively increased.

[0093] Example 4

[0094] Please refer to Figure 9 , Figure 9 This is a schematic diagram of a rotor conductive target 2 according to a fourth embodiment of the present invention. This embodiment differs from the first embodiment in that two rotor conductive targets 2 are provided, located on opposite sides of the stator coil 3. The two rotor conductive targets 2 are connected by a rotating shaft to maintain a constant spacing between them. In this embodiment, the centers of the two rotor conductive targets 2 and the center of the stator coil are perfectly aligned and separated by a predetermined distance. Furthermore, the two rotor conductive targets 2 are fixed by a rotating shaft, so their spacing remains constant, enabling synchronous rotation or translation.

[0095] If one rotor conductive target 2 is designated as the master rotor conductive target 2 and the other as the slave rotor conductive target 2, since the two rotor conductive targets 2 are fixed at a constant distance by a rotating shaft, if the master rotor conductive target 2 moves vertically away from the stator coil for some reason, the slave rotor conductive target 2 will correspondingly move vertically closer to the stator coil by the same distance, thus maintaining the total distance from the stator coil to the two rotor conductive targets 2. This structure ensures that the total distance between the stator coil and the two rotor conductive targets 2 is fixed. Regardless of how the rotor conductive targets 2 move, the distance (air gap) between the two rotor conductive targets 2 and the stator coil remains constant, resulting in virtually no change in the output signal amplitude, thereby unaffecting the output of angle information. In other words, compared to the first embodiment, the output signal amplitude of the inductive angle sensor with two rotor conductive targets 2 is larger, but is less affected by changes in the distance between the rotor conductive target 2 and the stator coil than with a single rotor conductive target 2. Therefore, by introducing two identical rotor conductive targets and their corresponding layout, this embodiment solves the problem of the output signal amplitude of existing inductive sensors being significantly affected by changes in the rotor-stator distance.

[0096] In summary, the embodiments of the present invention provide an inductive angle sensor. By designing a receiving coil as a single-wire wound structure with non-overlapping multi-pole pair receiving coils and monopole pair receiving coils, and by designing a rotor conductive target with a specific shape, the monopole pair receiving coils can achieve absolute angle measurement, while the multipole pair receiving coils can ensure the resolution of angle measurement, thereby achieving high-resolution absolute angle measurement. Since only two receiving coils are required, the area and number of layers of the PCB board can be saved, the parasitic capacitance caused by vias can be reduced, and the output interfaces required for the receiving coils can be reduced, thereby reducing the manufacturing cost of the inductive angle sensor and improving signal processing efficiency. In addition, each receiving coil only needs to be connected to the signal processing unit via a pair of output interfaces (input port and output port), and each inductive angle sensor only needs one signal processing unit (position sensor dedicated chip) to output angle information, which greatly reduces the manufacturing cost of the inductive angle sensor and improves the signal processing efficiency of the inductive angle sensor.

[0097] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any person skilled in the art who, without departing from the scope of the present invention, makes any equivalent substitution, modification, or other changes to the technical solution and technical content disclosed in the present invention shall be deemed to be within the scope of the present invention and still fall within the scope of protection of the present invention.

Claims

1. An inductive angle sensor, characterized in that: The invention comprises a coaxially arranged rotor conductive target and a stator coil, wherein the stator coil comprises an excitation coil and two receiving coils, and the two receiving coils are arranged 90 degrees apart around the axis, wherein: Each receiving coil is wound with a single wire and comprises a multi-pole pair of receiving coils and a monopole pair of receiving coils that do not overlap each other. The multi-pole pair of receiving coils has a plurality of first magnetic flux regions, and the plurality of first magnetic flux regions are configured such that, under the action of the excitation coil, the polarity of the current loop formed by two adjacent first magnetic flux regions is opposite, and the monopole pair of receiving coils has two second magnetic flux regions with opposite polarity. The rotor conductive target has a plurality of first blocking areas spaced apart from each other and adapted to the shape of the first magnetic flux area, and a second blocking area adapted to the shape of the second magnetic flux area. When the rotor conductive target rotates around the axis, the magnetic flux area of the first magnetic flux area covered by the first blocking areas and the magnetic flux area of the second magnetic flux area covered by the second blocking areas vary in a sinusoidal or cosine function with the rotation angle of the rotor conductive target.

2. The inductive angle sensor according to claim 1, wherein: The number of the first blocking areas of the rotor conductive target is half the number of the first magnetic flux areas of the multi-pole pair receiving coils.

3. The inductive angle sensor according to claim 2, wherein: When the rotor conductive target rotates by a predetermined angle, each of the first blocking areas can just cover all first magnetic flux areas with the same polarity in the multi-pole pair receiving coils.

4. The inductive angle sensor according to claim 3, wherein: The second blocking zone of the rotor conductive target is configured such that when each of the first blocking zones can just cover all first magnetic flux zones with the same polarity in the multi-pole pair receiving coils, the second blocking zone can just cover the second magnetic flux zone with the same polarity.

5. The inductive angle sensor according to any one of claims 1 to 4, characterized in that: There is also a central area between the two second magnetic flux areas of the monopole pair receiving coils, and the center of the rotor conductive target also has a central blocking area that can cover at least a portion of the central area.

6. The inductive angle sensor according to claim 1, wherein: The excitation coil and the two receiving coils each have a pair of output interfaces for connecting to a signal processing unit built into or externally connected to the inductive angle sensor. The signal processing unit is used to provide signals to the excitation coil and / or to process signals from the receiving coils.

7. The inductive angle sensor according to claim 1, wherein: There are two rotor conductive targets, which are respectively located on opposite sides of the stator coil. The two rotor conductive targets are connected by a rotating shaft to keep a constant distance between the two rotor conductive targets.

8. The inductive angle sensor according to claim 1, wherein: The inductive angle sensor is integrated into the PCB board.

9. The inductive angle sensor according to claim 8, wherein: The PCB board has four layers, wherein the two receiving coils are respectively located in the same two layers of the PCB board.

10. The inductive angle sensor according to claim 8, wherein: The multi-pole pair receiving coil is connected to the monopole pair receiving coil via a connecting portion, and the connecting portion is arranged in a direction perpendicular to the PCB board.

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