Magnetic Ring Encoder and Detection Method for Absolute Angle of Magnetic Ring Encoder

Abstract

The present invention relates to the technical field of encoders, and particularly to a high-performance magnetic ring encoder and a method for detecting the absolute angle of the magnetic ring encoder. The high-performance magnetic ring encoder includes a second multi-pole magnet, a first multi-pole magnet, a single-pole magnetic conductor assembly, a first group of Hall elements, a second group of Hall elements, and a third group of Hall elements; the single-pole magnetic conductor assembly has a toothed portion and a smooth portion, the first group of Hall elements and the second group of Hall elements are respectively arranged adjacent to the first multi-pole magnet and the second multi-pole magnet, the third group of Hall elements is arranged between the toothed portion and the smooth portion, and the three groups of Hall elements output corresponding detection signals according to the pole signals of the corresponding magnets. The present invention calibrates the rotation angle of the magnetic ring encoder by obtaining a mechanical angle with a certain accuracy, thereby greatly improving the measurement accuracy. The present invention is particularly suitable for meeting the actual requirements of angle detection of large-diameter shaft parts.

Description

Technical Field

[0001] The present invention relates to the technical field of encoders, and particularly to a magnetic ring encoder and a method for detecting the absolute angle of the magnetic ring encoder. Background Art

[0002] The magnetic ring encoder has the advantages of simple structure, high temperature resistance, oil resistance, shock resistance, small size, low cost, etc., and has unique advantages in applications with miniaturization and harsh environmental conditions.

[0003] The magnetic ring encoder mainly consists of two parts: a magnetic signal generating structure and a signal processing circuit. The magnetic signal generating source is called a magnet. According to the number of magnetic poles of the magnet, the magnetic ring encoder can be divided into a single-pole-pair magnetic ring encoder and a multi-pole-pair magnetic ring encoder. The commonly used multi-pole-pair magnetic ring encoder at present uses a double multi-pole-pair permanent magnet with mutually prime numbers of pole pairs in the radial inner and outer rings. The inner multi-pole-pair permanent magnet is the reference magnetic pole, and the outer multi-pole-pair permanent magnet is the measuring magnetic pole. By rotating the reference magnetic pole and the measuring magnetic pole coaxially, after collecting the original magnetic field signals by 4 linear Hall elements, the position relationship between the measuring magnetic pole and the reference magnetic pole, that is, the magnetic pole position characteristic value, is used to determine the magnetic pole interval where the measuring magnetic pole is currently located, and then the absolute angle value calculation formula is used to obtain the absolute angle of the magnetic ring encoder.

[0004] In the actual application process, when a higher-precision magnetic ring encoder is required, for example, when using a magnetic ring encoder on a large-diameter motor shaft or a large-diameter hollow rotating shaft, it is necessary to increase the number of magnetic poles of the magnet. The more the number of magnetic pole pairs, the higher the precision. However, when bonding hundreds of magnetic pole pairs together to form a multi-pole-pair permanent magnet, not only is it difficult to manufacture the magnetic pole pairs and they are not easy to bond, but also the thickness of the magnetic pole pairs will be sharply reduced to within 1 mm, which causes the problem that the multi-pole-pair permanent magnet is fragile and easy to break during the bonding process, thus making it impossible to greatly increase the number of magnetic pole pairs of the multi-pole-pair permanent magnet, and the measurement precision is also limited accordingly. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a magnetic ring encoder, aiming to overcome the defects that it is difficult to manufacture and bond magnetic pole pairs to form a magnet due to the increase in the number of magnetic pole pairs corresponding to the improvement of the precision of the magnetic ring encoder.

[0006] Another purpose of the present invention is to provide a method for detecting the absolute angle of a magnetic ring encoder, aiming to solve the problem that the precision of the magnetic ring encoder cannot be improved due to the large increase in the number of magnetic pole pairs of the multi-pole-pair permanent magnet.

[0007] In order to achieve the above-mentioned invention purposes, the technical solutions adopted by the present invention are as follows:

[0008] The magnetic ring encoder provided by the present invention includes:

[0009] A second multi-pole magnet, a first multi-pole magnet, and a single-pole magnetic conduction component are arranged coaxially and axially in sequence. Among them, the first multi-pole magnet includes m pairs of magnetic poles and 3 ≤ m < 23, the second multi-pole magnet includes n pairs of magnetic poles and 3 ≤ n < 23, m is greater than n and is a natural number that is relatively prime to each other. The single-pole magnetic conduction component includes a first annular magnetic conductor, a single-pole annular magnet, and a second annular magnetic conductor that are coaxially and axially arranged in close contact in sequence. The outer diameters of the outer rings of the first annular magnetic conductor and the second annular magnetic conductor are greater than the outer diameter of the single-pole annular magnet. Among them, the second annular magnetic conductor has a covering portion covering the outer circular surface of the first annular magnetic conductor. On the two surfaces of the covering portion opposite to the first annular magnetic conductor, a smooth portion and a toothed portion for forming an opening region are respectively provided. Among them, the opening direction of the opening region is consistent with the axial direction of the single-pole annular magnet, and P teeth are provided on its toothed portion and p ≥ 100;

[0010] The first group of Hall elements, including a first linear Hall sensor and a second linear Hall sensor, are arranged adjacent to the first multi-pole magnet and output a first group of detection signals according to the magnetic pole signals of the first multi-pole magnet;

[0011] The second group of Hall elements, including a third linear Hall sensor and a fourth linear Hall sensor, are arranged adjacent to the second multi-pole magnet and output a second group of detection signals according to the magnetic pole signals of the second multi-pole magnet;

[0012] The third group of Hall elements, including a fifth linear Hall sensor, a sixth linear Hall sensor, and a seventh linear Hall sensor, are arranged between the toothed portion and the smooth portion and output a corrected third group of detection signals according to the magnetic pole signals of the single-pole magnetic conduction component;

[0013] The corrected third group of detection signals includes: the detection signals of the d-axis and q-axis output by the fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor according to the magnetic pole signals of the single-pole magnetic conduction component, specifically including:

[0014] The fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor obtain original three-phase Hall signals after collecting the magnetic pole signals of the single-pole magnetic conduction component. The original three-phase Hall signals are the fifth detection signal, the sixth detection signal, and the seventh detection signal;

[0015] After performing zero-drift processing on the obtained original three-phase Hall signals, the detection signals of the d-axis and q-axis are output;

[0016] Angle resolution is respectively performed on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals to obtain a first electrical angle value, a second electrical angle value, and a third electrical angle value, specifically including:

[0017] Perform A / D conversion on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals to obtain a first group of voltage values, a second group of voltage values, and a third group of voltage values;

[0018] Based on the positive / negative nature and numerical magnitude of the voltage values in the first group of voltage values, the second group of voltage values, and the third group of voltage values, obtain the angular intervals where the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals are located;

[0019] According to the angular intervals, use the arctangent algorithm for the first group of voltage values, the second group of voltage values, and the third group of voltage values to obtain a first electrical angle value, a second electrical angle value, and a third electrical angle value.

[0020] Furthermore, the output signals of the first linear Hall sensor and the second linear Hall sensor have a 90-degree phase difference; the output signals of the third linear Hall sensor and the fourth linear Hall sensor have a 90-degree phase difference; the output signals of the fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor have a 120-degree phase difference.

[0021] Still further, the first linear Hall sensor, the third linear Hall sensor, and the fifth linear Hall sensor are aligned at one end.

[0022] Even further, the first multi-pole magnet is between the single-pole magnetic conduction component and the second multi-pole magnet.

[0023] Preferably, m and n are prime numbers and mn < 23 19.

[0024] More preferably, the magnetization directions of the first multi-pole magnet and the second multi-pole magnet are radial or axial, and there is an angular difference in the installation positions of the starting magnetic poles of the first multi-pole magnet and the second multi-pole magnet.

[0025] Even more preferably, the magnetization direction of the single-pole ring magnet in the single-pole magnetic conduction component is radial or axial.

[0026] In addition, the present invention also provides a method for detecting the absolute angle of a magnetic ring encoder, which is applied to the magnetic ring encoder with the above three-ring structure, and the detection method includes:

[0027] Obtain a first group of detection signals, a second group of detection signals, and a corrected third group of detection signals through the first group of Hall elements, the second group of Hall elements, and the third group of Hall elements respectively;

[0028] Perform angle resolution on the first set of detection signals, the second set of detection signals, and the corrected third set of detection signals respectively to obtain a first electrical angle value, a second electrical angle value, and a third electrical angle value;

[0029] According to the number of pole pairs m of the first multi-pole magnet, the number of pole pairs n of the second multi-pole magnet, the first electrical angle value, and the second electrical angle value, obtain a pole position characteristic value corresponding to the first multi-pole magnet;

[0030] According to the pole position characteristic value, determine the first pole interval where the first electrical angle value is currently located;

[0031] According to the first pole interval, the number of pole pairs m of the first multi-pole magnet, and the first electrical angle value, determine the initial mechanical angle formed by the first multi-pole magnet and the second multi-pole magnet ;

[0032] According to the initial mechanical angle, calibrate the tooth number interval where the third electrical angle value is currently located;

[0033] Use the determined tooth number interval, the tooth number p of the single-pole magnetic conductor assembly, and the third electrical angle value to determine the absolute angle of the magnetic ring encoder.

[0034] Further, the first set of detection signals includes: a first detection signal and a second detection signal output by a first linear Hall sensor and a second linear Hall sensor according to the pole signals of the first multi-pole magnet;

[0035] The second set of detection signals includes: a third detection signal and a fourth detection signal output by a third linear Hall sensor and a fourth linear Hall sensor according to the pole signals of the second multi-pole magnet.

[0036] Furthermore, after performing zero-drift processing on the obtained original three-phase Hall signals, output the detection signals of the d-axis and q-axis, specifically including:

[0037] Perform zero-drift processing on the collected original three-phase Hall signals according to the following formula (1);

[0038] Output the third set of detection signals of the d-axis and q-axis according to the following formula (2):

[0039] Formula (1)

[0040] Formula (2)

[0041] In the formula, 、 、 are the original three-phase Hall signals; is the signal drift amount; , , is the three-phase Hall voltage signal after removing the drift amount; is the included angle between the detected signal electrical angle of any linear Hall sensor in the third group of Hall elements and the horizontal direction, , are the output two-phase Hall voltage signals.

[0042] Furthermore, according to the number of pole pairs m of the first multi-pole magnet, the number of pole pairs n of the second multi-pole magnet, the first electrical angle value and the second electrical angle value, a pole position characteristic value corresponding to the first multi-pole magnet is obtained, which specifically includes:

[0043] Calculate the pole position characteristic value according to the following formula :

[0044] ,

[0045] In the formula, is the obtained first electrical angle value, is the obtained second electrical angle value.

[0046] Furthermore, according to the first pole interval, the number of pole pairs m of the first multi-pole magnet, and the first electrical angle value, the initial mechanical angle formed by the first multi-pole magnet and the second multi-pole magnet is determined , which specifically includes:

[0047] Calculate the initial mechanical angle according to the following formula :

[0048] ,

[0049] In the formula, is the first electrical angle value The number of the pole interval where it is currently located, .

[0050] Furthermore, according to the initial mechanical angle, the tooth number interval where the third electrical angle value is currently located is calibrated; then, using the determined tooth number interval, the tooth number p of the single-pole magnetic conductor assembly, and the third electrical angle value, the absolute angle of the magnetic ring encoder is determined, which specifically includes:

[0051] According to the obtained initial mechanical angle, the tooth number interval where the third electrical angle value is currently located is calibrated by referring to the index table;

[0052] Using the determined tooth number interval, the tooth number p of the single-pole magnetic conductor assembly, and the third electrical angle value, the absolute angle of the magnetic ring encoder is determined according to the following formula:

[0053] ,

[0054] In the formula, is the absolute angle output by the magnetic ring encoder, is the value of the third electrical angle is the number of the tooth number interval where it is currently located, .

[0055] Beneficial effects of the present invention: In the present invention, one surface of the first annular magnetic conductor in the single-pole magnetic conductor assembly is set as a toothed portion, and one surface of the second annular magnetic conductor is set as a smooth portion. When the single-pole magnetic conductor assembly rotates coaxially for one week while maintaining the opposite situation, the number of periods in the detection signal collected by the Hall element corresponds one-to-one to the number of teeth of the toothed portion. That is, when the toothed portion has P teeth, a detection signal containing P periods will be obtained, which exactly coincides with the detection signal collected by the multi-pole magnet with P pole pairs using the Hall element. At this time, the single-pole magnetic conductor assembly can be regarded as a multi-pole magnet with P pole pairs.

[0056] On this basis, a multi-pole magnet with P pole pairs is axially added on the basis of the original two-ring multi-pole magnet. Due to the increase in the number of pole pairs, it will lead to problems such as difficulty in manufacturing and bonding the magnetic pole pairs in the multi-pole magnet. The present invention uses a single-pole magnetic conductor assembly to perfectly avoid this defect. By means of machining, it is easy to machine a toothed portion with P teeth on the first annular magnetic conductor, thus realizing a large increase in the number of pole pairs of the multi-pole magnet, thereby greatly improving the measurement accuracy of the encoder, and at the same time being able to meet the actual needs of angle detection for large-diameter shaft parts. Description of the Drawings

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0058] Figure 1 A cross-sectional view showing the structure of the magnetic ring encoder according to the embodiment of the present application;

[0059] Figure 2 A perspective view showing the structure of the magnetic ring encoder according to the embodiment of the present application;

[0060] Figure 3 A flowchart showing the method for detecting the absolute angle of the magnetic ring encoder according to the embodiment of the present application;

[0061] Figure 4Shows the schematic diagram of signal detection of two linear Hall sensors in the embodiments of the present application;

[0062] Figure 5 Shows the schematic diagram of signal detection of two linear Hall elements in the embodiments of the present application;

[0063] Figure 6 Shows the schematic diagram of signal detection of three linear Hall sensors in the embodiments of the present application;

[0064] Figure 7 Shows the schematic diagram of signal detection of three linear Hall sensors in the embodiments of the present application;

[0065] Figure 8 Shows the schematic diagram of eliminating zero drift by using three Hall signals in the embodiments of the present application;

[0066] Figure 9 Shows the schematic diagram of synthesizing two-phase Hall signals in the embodiments of the present application;

[0067] Figure 10 Shows Figure 1-2 There is an angular difference in the starting magnetic pole installation positions between the second multi-pole magnet and the first multi-pole magnet in the schematic diagram;

[0068] Figure 11 Shows the schematic diagram of the number of eigenvalue values of the magnetic pole positions in the embodiments of the present application. Detailed implementation manners

[0069] Hereinafter, example embodiments will be described more comprehensively with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. These embodiments are provided so that this invention will be more complete and thorough, and the concept of the example embodiments will be fully conveyed to those skilled in the art. Identical reference numerals in the figures denote identical or similar parts, and thus their repetitive description will be omitted.

[0070] In addition, the described features, structures or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present invention.

[0071] It should be understood that although the terms first, second, third, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used for distinction. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0072] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of exemplary embodiments. The modules or processes in the accompanying drawings are not necessarily essential for implementing the present invention, and thus cannot be used to limit the protection scope of the present invention.

[0073] In the actual application process of existing multi-pole magnetic ring encoders with two-ring pole pairs being relatively prime, it will inevitably encounter the situation of large-diameter shafts. In this case, for the two-ring multi-pole magnets sleeved on the large-diameter shaft, it is necessary to correspondingly increase the pole pairs of its own magnets. In an ideal situation, that is, under the condition that the two-ring multi-pole magnets have no installation error and no noise influence, the multi-pole magnetic ring encoder with two-ring pole pairs being relatively prime can exactly measure the rotation angle of large-diameter shaft parts. However, the technical personnel of this application found that in the actual application process, when the pole pairs of the two-ring multi-pole magnets increase to a certain number, the detection signals obtained by the Hall elements will be exactly the same in a certain angular interval, which will cause the multi-pole magnetic ring encoder with two-ring pole pairs being relatively prime to be unable to measure the rotation angle of large-diameter shaft parts, resulting in the failure of the measurement accuracy of this magnetic ring encoder.

[0074] Theoretically, adding a multi-pole magnet with a very large number of pole pairs axially to the existing two-ring multi-pole magnet can obtain the actual rotation angle of the encoder, so as to meet the detection requirements of large-diameter shaft workpieces.

[0075] However, a substantial increase in the pole pairs of the magnet will cause the thickness of the magnetic pole pairs to be reduced to within 1 mm, and hundreds of magnetic pole pairs need to be bonded together to form a magnet. First, the process of making the magnetic pole pairs is difficult to achieve, and the bonding process is also very difficult. Finally, the formed multi-pole magnet is also fragile and easy to break, and ultimately it is impossible to substantially increase the pole pairs of the multi-pole magnet, and the measurement accuracy is thus limited.

[0076] To solve the above problems, the present invention provides a high-performance magnetic ring encoder, which includes a single-pole magnetic conductor assembly. In the present invention, one surface of the first annular magnetic conductor in the single-pole magnetic conductor assembly is set as a toothed portion, and one surface of the second annular magnetic conductor is set as a smooth portion, and the smooth portion and the toothed portion are kept opposite to each other. When the single-pole magnetic conductor assembly rotates coaxially for one week, the number of periods in the detection signal collected by the Hall element corresponds one by one to the number of teeth of the toothed portion, that is, if the toothed portion has P teeth, a detection signal containing P periods will be obtained, which exactly coincides with the detection signal collected by the Hall element of a multi-pole magnet with P pole pairs. At this time, the single-pole magnetic conductor assembly can be regarded as a multi-pole magnet with P pole pairs.

[0077] Furthermore, the present invention uses a single pair of pole magnetic assemblies, which can perfectly avoid the defects of difficult machining and bonding. By means of machining, it is easy to machine a tooth-shaped part with P teeth on the first annular magnetic conductor, thus realizing a significant increase in the number of pole pairs of the multi-pole magnet, thereby greatly improving the measurement accuracy of the encoder, and at the same time being able to meet the actual needs of angle detection for large-diameter shaft parts.

[0078] The technical solution of the present application will be described in detail below with reference to the accompanying drawings.

[0079] Figure 1 A cross-sectional view showing the structure of a high-performance magnetic ring encoder according to an embodiment of the present application.

[0080] Figure 2 A perspective view showing the structure of a high-performance magnetic ring encoder according to an embodiment of the present application.

[0081] As Figure 1 、 Figure 2 shown, the present application provides a high-performance magnetic ring encoder 100, including: a second multi-pole magnet 120, a first multi-pole magnet 110, and a single pair of pole magnetic assemblies 130, which are coaxially arranged axially in sequence in a first space plane. The single pair of pole magnetic assemblies 130 includes a first annular magnetic conductor 135, a single pair of pole annular magnets 134, and a second annular magnetic conductor 136, which are coaxially arranged axially and tightly attached to each other in sequence. The outer diameters of the outer rings of the first annular magnetic conductor 135 and the second annular magnetic conductor 136 are greater than the outer diameter of the single pair of pole annular magnet 134. Among them, the second annular magnetic conductor 136 has a covering portion covering the outer circular surface of the first annular magnetic conductor 135. On the two surfaces of the covering portion opposite to the first annular magnetic conductor 135, a smooth portion and a tooth-shaped portion for forming an opening region are respectively provided. In this structure, the overall shape of the single pair of pole magnetic assemblies 130 tends to be closed in its radial cross-section. Among them, the opening direction of the opening is consistent with the axial direction of the single pair of pole annular magnet 134, and P teeth are provided on its tooth-shaped portion and p≥100.

[0082] The first multi-pole magnet 110 includes m pairs of magnetic poles and 3≤m<23, the second multi-pole magnet 120 includes n pairs of magnetic poles and 3≤n<23, m is greater than n and mn<23 19, the number of teeth p of the single pair of pole magnetic assemblies 130 can be 100, 200, 300, 400, 500, 600, 700, 800, or even more. The larger the number of P, the higher the accuracy of the final magnetic ring encoder. For example, according to some embodiments, m and n are prime numbers and relatively prime to each other. As Figure 1 、 2 shown, in this embodiment, m is 5, n is 3, and p is 100, but the present application is not limited thereto.

[0083] According to an exemplary embodiment of the present application, the first multi-pole magnet 110 is interposed between the single-pole magnetic conductor assembly 130 and the second multi-pole magnet 120. The number of pole pairs m of the first multi-pole magnet 110 is greater than the number of pole pairs n of the second multi-pole magnet 120. This is because the diameter of the first multi-pole magnet 110 is larger than that of the second multi-pole magnet 120. In order to make the magnet sizes uniform, the number of magnetic pole pairs of the first multi-pole magnet 110 is greater than that of the second multi-pole magnet 120.

[0084] In the present application, the number of pole pairs m of the first multi-pole magnet 110 and the number of pole pairs n of the second multi-pole magnet 120 are defined in order to obtain effective detection signals during actual application and avoid signal overlap within a certain angular range.

[0085] According to some embodiments of the present application, the magnetization direction of the first multi-pole magnet 110 can be radial or axial. In Figure 1 、 2 In the illustrated embodiment, the magnetization direction of the first multi-pole magnet 110 is set to axial. The magnetization direction of the second multi-pole magnet 120 can also be radial or axial. Figure 1 、 2 In the illustrated embodiment, the magnetization direction of the second multi-pole magnet 120 is set to axial. Similarly, the magnetization direction of the single-pole magnetic conductor assembly 130 can also be radial or axial. Figure 1 、 2 In the illustrated embodiment, the magnetization direction of the single-pole ring magnet 134 is set to axial. The present application does not limit the magnetization direction.

[0086] Both the first multi-pole magnet 110 and the second multi-pole magnet 120 can be formed by adhering multiple magnetic pole pairs, but are not limited thereto. According to the embodiments of the present application, the magnet can be made of neodymium iron boron permanent magnet material, directly attached to the rotating shaft, or fixed to the rotating shaft. When installed and fixed, there is an angular difference in the starting magnetic poles between the first multi-pole magnet 110 and the second multi-pole magnet 120.

[0087] As Figure 1 、 2 shown, the high-performance magnetic ring encoder 100 further includes a first set of Hall elements, a second set of Hall elements, and a third set of Hall elements for detecting magnetic signals generated by the multi-pole magnet.

[0088] The first set of Hall elements includes a first linear Hall sensor 111 and a second linear Hall sensor 112, which are arranged adjacent to the first multi-pole magnet 110 and output a first set of detection signals according to the magnetic pole signals of the first multi-pole magnet 110. The output signals of the first linear Hall sensor 111 and the second linear Hall sensor 112 have a 90-degree phase difference.

[0089] The second group of Hall elements, including a third linear Hall sensor 121 and a fourth linear Hall sensor 122, are arranged adjacent to the second multi-pole magnet 120, and output a second group of detection signals according to the magnetic pole signals of the second multi-pole magnet 120. The output signals of the third linear Hall sensor 121 and the fourth linear Hall sensor 122 have a phase difference of 90 degrees.

[0090] The third group of Hall elements, including a fifth linear Hall sensor 131, a sixth linear Hall sensor 132, and a seventh linear Hall sensor 133, are arranged between the toothed portion and the smooth portion, and output a corrected third group of detection signals according to the magnetic pole signals of the single-pole magnetic conduction component 130. The output signals of the fifth linear Hall sensor 131, the sixth linear Hall sensor 132, and the seventh linear Hall sensor 133 have a phase difference of 120 degrees.

[0091] It should be noted here that after the single-pole magnetic conduction component 130 rotates one week around the axis, the third group of Hall elements will collect three original detection signals, and the number of cycles in each original detection signal is exactly the same as the number of teeth in the toothed portion of the first annular magnetic conduction body 135. That is, the number of teeth P of the toothed portion coincides with the number of cycles in the detection signal. Therefore, the single-pole magnetic conduction component 130 with P teeth can be regarded as a multi-pole magnet with a pole pair number of P.

[0092] According to the toothed structure, it can be known that each tooth contains a tooth top and a tooth recess. According to the distances between the tooth top, the tooth recess and the smooth portion, the change of the magnetic field intensity can be reflected. That is, according to the characteristics of the magnetic field intensity, when the distance between the tooth top and the smooth portion is less than the distance between the tooth recess and the smooth portion, the magnetic field intensity between the tooth top and the smooth portion will be greater than the magnetic field intensity between the tooth recess and the smooth portion.

[0093] According to some embodiments, in the above encoder structure, the first linear Hall sensor 111, the third linear Hall sensor 121, and the fifth linear Hall sensor 131 are aligned at one end; and when the above encoder works, the first multi-pole magnet 110, the second multi-pole magnet 120, and the single-pole magnetic conduction component 130 rotate together with the rotating shaft, while the three groups of Hall elements remain stationary.

[0094] Figure 3 The flowchart of the absolute angle detection method of the magnetic ring encoder according to the embodiment of the present application is shown.

[0095] The present application also provides a detection method for the absolute angle of the above magnetic ring encoder, as Figure 3 shown, including:

[0096] In step S310, a first set of detection signals, a second set of detection signals, and a corrected third set of detection signals are obtained through a first set of Hall elements, a second set of Hall elements, and a third set of Hall elements, respectively.

[0097] The magnetic ring encoder provided by this application includes three sets of multi-pole magnets: a second multi-pole magnet 120, a first multi-pole magnet 110, and a single-pole magnetic conduction assembly 130. Among them, the number of pole pairs of the second multi-pole magnet 120 and the first multi-pole magnet 110 are relatively prime. The three sets of magnets are isolated by isolation means to prevent magnetic field coupling. The magnetic fields around the three sets of multi-pole magnets are sinusoidally distributed in the circumferential direction.

[0098] Two linear Hall sensors in the first set of Hall elements and the second set of Hall elements respectively corresponding to the first multi-pole magnet 110 and the second multi-pole magnet 120 are arranged at an included angle of 90° electrical angle. The following combines Figure 4 、 5 to introduce the principle of using two linear Hall sensors to detect the magnetic signals of the second multi-pole magnet 120 or the first multi-pole magnet 110.

[0099] Figure 4 Shows the signal detection schematic diagram of two linear Hall sensors in the embodiment of this application.

[0100] Figure 5 Shows the schematic diagram of the detection signals of two linear Hall elements in the embodiment of this application.

[0101] When the magnet rotates one week along with the rotating shaft, the magnetic field change at any point in the space where it is located is regular. Using two linear Hall sensors with a 90° electrical angle difference can convert this change into sine and cosine electrical signals, and the change frequency of this electrical signal is the same as the rotation frequency of the magnetic pole. As Figure 4 、 5 shown, for the second multi-pole magnet 120 with 3 pole pairs, when the magnet rotates one week, the linear Hall sensors A and B respectively detect three cycles of sine and cosine signals, that is, a set of detection signals. The first set of detection signals can be obtained through the first set of Hall elements arranged by the first multi-pole magnet 110. The second set of detection signals can be obtained through the second set of Hall elements arranged by the second multi-pole magnet 120.

[0102] In the actual process, the two Hall arrangement methods often choose to arrange at an included angle of 90° in electrical angle. However, it is very difficult for the two Hall methods to eliminate the errors caused by processing or assembly, and it is also difficult to suppress the harmonic errors existing in the magnetic field. Increasing the number of Hall elements or arranging them symmetrically, the main effect is to use the symmetric cancellation method to reduce mechanical errors, and at the same time, the harmonic components can also be cancelled. For this reason, in this application, a three-Hall arrangement method is set between the tooth-shaped part and the smooth part of the single-pole magnetic conductor assembly 130, and higher calculation accuracy can be obtained when the electrical angles of the three Hall elements are at 120°.

[0103] The third group of Hall elements is arranged between the tooth-shaped part and the smooth part, and the three linear Hall sensors are arranged at intervals with an included angle of 120° in electrical angle. The following combines Figures 6-9 to introduce the principle of the three linear Hall sensors detecting the magnetic signal of the single-pole magnetic conductor assembly 130.

[0104] Figure 6 Shows the schematic diagram of the signal detection of the three linear Hall sensors in the embodiment of this application.

[0105] Figure 7 Shows the schematic diagram of the three linear Hall sensors detecting signals in the embodiment of this application.

[0106] Figure 8 Shows the schematic diagram of using the three Hall signals to eliminate zero drift in the embodiment of this application.

[0107] Figure 9 Shows the schematic diagram of synthesizing two-phase Hall signals in the embodiment of this application.

[0108] According to the above principle, it is easy to know that the magnetic field change can also be converted into sine and cosine electrical signals by using three linear Hall sensors with electrical angles differing by 120°. As Figure 6 、 7 shows, for a group of multi-pole magnets with 6 poles of the single-pole magnetic conductor assembly 130, when the magnet rotates one week, the fifth linear Hall sensor 131, the sixth linear Hall sensor 132 and the seventh linear Hall sensor 133 respectively detect six cycles of sine and cosine signals, that is, the original three-phase Hall signals. The original three-phase Hall signals here are respectively represented by Figure 8 in 、 、 and corresponds to the detection signal of the fifth linear Hall sensor 131; corresponds to the detection signal of the sixth linear Hall sensor 132; corresponds to the detection signal of the seventh linear Hall sensor 133.

[0109] Due to issues such as Hall arrangement and mechanical assembly, the original three-phase Hall signal , , Some error signals are superimposed to synthesize the components with a 90° phase difference between the two phases. , There is a high probability that the zero point will drift.

[0110] Therefore, it is necessary to process the zero drift of the collected original three-phase Hall signal, such as Figure 8 As shown, the calculation is performed according to the following formula:

[0111] ,

[0112] In the formula, , , is the original three-phase Hall signal; is the signal drift; , , It is the three-phase Hall voltage signal after removing the drift.

[0113] Then, the three-phase Hall voltage signal with zero drift removed is synthesized into two phases with a phase difference of 90°. , Signals, such as Figure 9 As shown, the following formula is used for conversion:

[0114] ,

[0115] In the formula, is the angle between the electrical angle of the detection signal of any linear Hall sensor in the third group of Hall elements and the horizontal direction, , The output two-phase Hall voltage signal is the modified third set of detection signals.

[0116] At this time, the third group of detection signals with a corrected two-phase phase difference of 90° can be approximately regarded as sine and cosine detection signals collected by two linear Hall sensors. In order to facilitate the subsequent text description, this application approximately regards the third group of Hall elements as two linear Hall sensors arranged at an angle of 90° in electrical angle.

[0117] Of course, the second multi-pole magnet 120 and the first multi-pole magnet 110 of the present application can also adopt the form of three Hall sensors to improve the measurement accuracy, and then use the above formula to convert the collected detection signal into a two-phase detection signal with a phase difference of 90°.

[0118] In step S320, angle calculations are respectively performed on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals to obtain a first electrical angle value, a second electrical angle value, and a third electrical angle value.

[0119] After positive and cosine signals are obtained by applying linear Hall sensors, digital voltage values with a certain number of bits can be obtained through an A / D conversion circuit. That is, after A / D conversion is respectively performed on the first group of detection signals, the second group of detection signals, or the corrected third group of detection signals, a first group of voltage values, a second group of voltage values, or a third group of voltage values are obtained. Although the digital voltage values at this time have a certain relationship with the measured angle values of the encoder, they are not the measured angle values of the encoder, and angle calculation is still required.

[0120] For the signals of each group of magnetic poles, the positions of the two linear Hall sensors in space differ by 90°, such that the positive and cosine signals output by the two linear Hall sensors differ by 90° in phase. At this time, the signal with a leading phase can be regarded as the sine signal, and the signal with a lagging phase can be regarded as the cosine signal. Dividing the sine signal by the cosine signal can obtain the tangent value of the signal at this point, and then performing an arctangent process on the tangent value can obtain the electrical angle value of this point position.

[0121] Since the interval of the tangent function is [-90°, 90°], directly performing angle calculation according to the above process will lead to an incorrect interval for angle calculation. Therefore, it is necessary to solve the interval error problem through a method of dividing intervals, that is, according to the positive or negative nature and numerical magnitude of the voltage values in the first group of voltage values, the second group of voltage values, or the third group of voltage values, the electrical angle interval where the first group of detection signals, the second group of detection signals, or the corrected third group of detection signals are located is obtained.

[0122] Taking the angle calculation of a group of magnetic poles as an example, the 360° of this group of magnetic poles can be divided into 8 equal-length intervals at intervals of 45°. By judging the magnitude and positive or negative nature of the voltage values detected by the two linear Hall elements, the position where the Hall signal is located at this time is judged, and the implementation principle of the interval division arctangent algorithm is shown in Table 1 below. Where VA and VB are linear Hall detection signals with a 90° phase difference.

[0123] Table 1 Division of angle intervals

[0124] ,

[0125] Through the above division of angle intervals, the conversion from the signals collected by the Hall elements to angle signals can be realized, and the range of the converted electrical angle interval is [0°, 360°].

[0126] For the magnetic ring encoder of the present application, according to the positive and negative nature and numerical magnitude of the voltage values in the first group of voltage values, the second group of voltage values, and the third group of voltage values, the angular intervals where the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals are located can be obtained. According to this angular interval, the arctangent algorithm can be used to obtain the first electrical angle value, the second electrical angle value, and the third electrical angle value for the first group of voltage values, the second group of voltage values, or the third group of voltage values according to Table 1. The electrical angle value here refers to the electrical angle value of a single pair of magnetic pole cycles, simply referred to as the single-cycle electrical angle value.

[0127] During the angle measurement process, three groups of multi-pole magnets rotate simultaneously with the rotating shaft, and the linear Hall elements remain stationary to receive the changing magnetic field signals generated by the magnetic poles during rotation. The induction signals of the linear Hall are processed by the above-mentioned arctangent look-up table method, and the electrical angle value of a single pair of magnetic pole cycles of the measured magnet can be obtained. After determining the electrical angle value of a single cycle, then determining the magnetic pole interval where the electrical angle value of a single cycle is located, and finally determining the tooth number interval on the single-pole magnetic conductor assembly 130, the absolute angle value detected by the magnetic ring encoder can be finally obtained.

[0128] In the absolute angle detection method of the magnetic ring encoder provided in the present application, first, according to the two groups of detection signals of the second multi-pole magnet 120 and the first multi-pole magnet 110, an initial mechanical angle with a certain accuracy is determined, and then this initial mechanical angle is used to calibrate which specific tooth number interval in the tooth number interval of the single-pole magnetic conductor assembly 130 the single-cycle electrical angle value of the single-pole magnetic conductor assembly 130 is currently in, and finally the mechanical angle of the magnetic ring encoder is calculated using the calculation formula of the mechanical angle value. The mechanical angle mentioned in the present application is also called the absolute angle.

[0129] Next, the present application will describe in detail how to obtain an initial mechanical angle with a certain accuracy.

[0130] In the present application, the calculation of the initial mechanical angle can be carried out according to the following formula:

[0131] Or ,

[0132] In the formula, is the initial mechanical angle, is the single-cycle electrical angle value measured by the linear Hall sensor on the first multi-pole magnet 110, is the first magnetic pole interval where it is located; m is the number of magnetic pole pairs of the first multi-pole magnet 110. Here, is also called the first electrical angle value.

[0133] For Figure 1-2For the encoder shown in the figure, there is an angular difference between the starting magnetic pole installation positions of the second multi-pole magnet 120 and the first multi-pole magnet 110. , as Figure 10 shown, the initial mechanical angle can also be expressed as:

[0134] or ,

[0135] In the formula, is the initial mechanical angle, is the single-period electrical angle value measured by the linear Hall sensor on the second multi-pole magnet 120, is the second magnetic pole interval where it is located; n is the number of pole pairs of the second multi-pole magnet 120. It is also called the second electrical angle value.

[0136] Therefore, on the basis of having obtained the first electrical angle value or the second electrical angle value, as long as the corresponding magnetic pole interval is determined, the initial mechanical angle value can be calculated according to the above formulas (3) - (6).

[0137] In step S330, according to the number of pole pairs m of the first multi-pole magnet 110, the number of pole pairs n of the second multi-pole magnet 120, the first electrical angle value, and the second electrical angle value, determine the first magnetic pole interval corresponding to the first electrical angle value.

[0138] When the linear Hall sensor on the first multi-pole magnet 110 measures two identical single-period electrical angle values, the two single-period electrical angle values measured by the linear Hall sensor on the corresponding second multi-pole magnet 120 are different. Thus, the number of pole pairs, that is, the magnetic pole interval, where the single-period electrical angle of the first multi-pole magnet 110 is currently located can be distinguished.

[0139] For the magnet structure of the magnetic ring encoder provided in this application, when the greatest common divisor of the number of pole pairs m and n of the first multi-pole magnet 110 and the second multi-pole magnet 120 is 1, that is, they are relatively prime, each pair of poles of the first multi-pole magnet 110 has a corresponding non-repeating pole part of the second multi-pole magnet 120. The following is proved by contradiction.

[0140] Suppose there exists a positive integer N m1 , N m2 , N n1 , N n2 , N m1 ≠N m2 , such that the following formula holds:

[0141] ,

[0142] ,

[0143] Among them, is the single - cycle electrical angle value measured by the linear Hall sensor on the first multi - pair pole magnet 110, N m1 , N m2 ∈[1, m], is the first magnetic pole interval corresponding to the two measurements ; is the single - cycle electrical angle value measured by the linear Hall sensor on the second multi - pair pole magnet 120, N n1 , N n2 ∈[1, n], is the second magnetic pole interval corresponding to the two measurements ; is the installation angle difference between the starting points of a pair of magnetic poles in the two groups of magnets.

[0144] Subtracting the two equations in formula (7), we can get:

[0145]

[0146] Since m and n are relatively prime, and N m1 N m2 ∈[1, m - 1], so formula (8) never holds, that is, formula (7) never holds.

[0147] Further from formula (8), we can get:

[0148]

[0149] Formula (9) does not hold for any different N m and its corresponding N n . That is, for the magnetic pole pairs in the different first multi - pair pole magnets 110 and the corresponding magnetic pole pairs in the second multi - pair pole magnets 120, formula (9) does not hold. Thus, it can be proved that when the linear Hall sensor on the first multi - pair pole magnet 110 measures the same single - cycle electrical angle value, the two single - cycle electrical angle values measured by the linear Hall sensor on the corresponding second multi - pair pole magnet 120 are different. In this way, the magnetic pole interval where the first angle value is located can be distinguished through the positional relationship between the first multi - pair pole magnet 110 and the second multi - pair pole magnet 120.

[0150] Combining formula (3) and formula (5), we can get:

[0151]

[0152] It can be seen that the value on the right side of the expression is a single-cycle electrical angular value that does not contain the current sampling point. Its magnitude only depends on the pole interval numbers of the second multi-pole magnet 120 and the first multi-pole magnet 110. When the pole interval number group is fixed, its value is a constant, and this constant is the characteristic value of the mapping interval number group.

[0153] Let , and define it as the pole position characteristic value. It can be seen from formula (10) that when the number of pole pairs of the first multi-pole magnet 110 and the second multi-pole magnet 120 remains unchanged, the pole position characteristic value remains unchanged. When at least one of them changes, the pole position characteristic value will also change, otherwise equation (9) holds, which contradicts the premise that the number of pole pairs is relatively prime. Therefore, the pole interval where the current electrical angle is located can be determined by calculating the pole position characteristic value.

[0154] When ≠0, that is, the starting points of a pair of poles of the second multi-pole magnet 120 and the first multi-pole magnet 110 do not coincide, and it is impossible to make them coincide by changing the coordinate origin, the pole position characteristic value λ has a total of m + n different values. As shown in Figure 11 .

[0155] Figure 11 shows a schematic diagram of the number of values of the pole position characteristic value in an embodiment of the present application.

[0156] Figure 11 In, the first multi-pole magnet 110 has m pole pairs, and m takes 5. Therefore, 5 boxes are used to represent the planar expansion of 5 pairs of poles. The second multi-pole magnet 120 has n pole pairs, and n takes 3. After its planar expansion, it is equivalent to introducing 3 vertical lines into 5 boxes. Since ≠0, there are a total of m + n + 1 lines that divide it into m + n parts. That is, for an encoder with a 5-pole magnet and a 3-pole magnet, the position characteristic value has a total of 8 different values. By analogy, for an encoder with a 23-pole magnet and a 19-pole magnet, the pole position characteristic value has a total of 42 different values.

[0157] After the second multi-pole magnet 120 and the first multi-pole magnet 110 are installed, the value of has been determined, so the m + n different values are already fixed values. According to the number of pole pairs m of the first multi-pole magnet 110, the number of pole pairs n of the second multi-pole magnet 120, the first electrical angle value, and the second electrical angle value, the pole position characteristic value corresponding to the first multi-pole magnet 110 can be determined. Taking the magnetic ring encoder structure shown in Figure 10 as an example, When θ = 40° and the rotation direction of the magnet is clockwise, the pole position characteristic values obtained by calibration and the corresponding pole intervals on the first multi-pole magnet 110 are shown in Table 2.

[0158] Table 2 Corresponding relationship between λ value and pole interval of the first multi-pole magnet

[0159]

[0160] Based on the corresponding relationship between λ and the pole interval in Table 2, the identification of the pole position can be completed, that is, according to the pole position characteristic value, the first pole interval where the first electrical angle value is currently located is calculated.

[0161] In step S340, according to the first pole interval, the number of pole pairs m of the first multi-pole magnet 110, and the first electrical angle value, the initial mechanical angle formed by the first multi-pole magnet 110 and the second multi-pole magnet 120 is determined. .

[0162] After determining the first electrical angle value and the first pole interval where the electrical angle value is located, the initial mechanical angle formed by the first multi-pole magnet 110 and the second multi-pole magnet 120 can be obtained according to formula (3).

[0163] In step S350, according to the initial mechanical angle, the tooth number interval where the third electrical angle value is currently located is calibrated.

[0164] On the premise of obtaining the initial mechanical angle, the tooth number interval where the third electrical angle value of the single-pole magnetic conduction component 130 is currently located can be calibrated by using this initial mechanical angle.

[0165] In this application, the tooth number interval has the following corresponding relationship with the initial mechanical angle:

[0166]

[0167] Therefore, an index table is established for the corresponding relationship between the initial mechanical angle and the tooth number interval. The first column of the index table is the value of the initial mechanical angle, and the second column is the interval number of the tooth number interval corresponding to this initial mechanical angle. Since the initial mechanical angle is an absolute angle and its value range is [0°, 360°], the first row of the first column is the number 0, and the last row of the first column is the number 360.

[0168] Exemplarily, assuming that the number of teeth P of the single-pole magnetic conduction component 130 is 5, the initial mechanical angles obtained by calibration and the corresponding tooth number intervals are shown in Table 3.

[0169] Table 3 Index table of the relationship between the initial mechanical angle and the tooth number interval in the single-pole magnetic conduction component

[0170]

[0171] Therefore, only by determining the degree of the initial mechanical angle can the numerical value of the tooth number range be obtained by looking up the table. However, it should be noted that when making the table, the number of rows in the column of the initial mechanical angle needs to be set to be much larger than the number of pole pairs of the single-pole-pair magnet conductor assembly 130, that is, the tooth number P, so as to greatly improve the accuracy of the magnetic ring encoder.

[0172] For example: in Table 3, the number of rows in the column of the initial mechanical angle is 360 rows, while the tooth number P of the single-pole-pair magnet conductor assembly 130 is only 5, meeting the requirement of being much larger than the tooth number P of the single-pole-pair magnet conductor assembly 130.

[0173] Suppose the tooth number P of the single-pole-pair magnet conductor assembly 130 is 360. The number of rows in the column of the initial mechanical angle can be set to 360 rows, that is, each degree of the initial mechanical angle corresponds to a tooth number range of the single-pole-pair magnet conductor assembly 130; similarly, the number of rows in the column of the initial mechanical angle can also be set to 3600 rows, so that each 0.1 degree of the initial mechanical angle corresponds to a tooth number range of the single-pole-pair magnet conductor assembly 130, and thus the accuracy of the magnetic ring encoder is increased by 10 times. Correspondingly, the accuracy can also be increased to 20 times, 30 times, or even 100 times or more times. This is the significance of the number of rows being much larger than the number of pole pairs.

[0174] In step S360, the absolute angle of the magnetic ring encoder is determined according to the following formula by using the determined tooth number range, the tooth number p of the single-pole-pair magnet conductor assembly 130, and the third electrical angle value:

[0175]

[0176] In the formula, is the absolute angle output by the magnetic ring encoder, is the third electrical angle value is the number of the tooth number range currently located, .

[0177] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A magnetic ring encoder, characterized in that, Comprising: A second multi-pole magnet, a first multi-pole magnet and a single-pole magnetic conductor assembly arranged coaxially and axially in sequence. Among them, the first multi-pole magnet includes m pairs of magnetic poles and 3 ≤ m < 23, the second multi-pole magnet includes n pairs of magnetic poles and 3 ≤ n < 23, m is greater than n and is a natural number that is relatively prime to each other. The single-pole magnetic conductor assembly includes a first annular magnetic conductor, a single-pole annular magnet and a second annular magnetic conductor that are coaxially and axially closely attached and installed in sequence, and the outer ring diameters of the first annular magnetic conductor and the second annular magnetic conductor are greater than the outer ring diameter of the single-pole annular magnet. Among them, the second annular magnetic conductor has a covering portion covering the outer circular surface of the first annular magnetic conductor. On the two surfaces of the covering portion opposite to the first annular magnetic conductor, there are respectively provided a smooth portion and a tooth-shaped portion for forming an opening region. Among them, the opening direction of the opening region is consistent with the axial direction of the single-pole annular magnet, and P teeth are provided on its tooth-shaped portion and p ≥ 100; A first group of Hall elements, including a first linear Hall sensor and a second linear Hall sensor, are arranged adjacent to the first multi-pole magnet and output a first group of detection signals according to the magnetic pole signals of the first multi-pole magnet; A second group of Hall elements, including a third linear Hall sensor and a fourth linear Hall sensor, are arranged adjacent to the second multi-pole magnet and output a second group of detection signals according to the magnetic pole signals of the second multi-pole magnet; A third group of Hall elements, including a fifth linear Hall sensor, a sixth linear Hall sensor and a seventh linear Hall sensor, are arranged between the tooth-shaped portion and the smooth portion and output a corrected third group of detection signals according to the magnetic pole signals of the single-pole magnetic conductor assembly; The corrected third group of detection signals includes: the detection signals of the d-axis and q-axis output by the fifth linear Hall sensor, the sixth linear Hall sensor and the seventh linear Hall sensor according to the magnetic pole signals of the single-pole magnetic conductor assembly, specifically including: The fifth linear Hall sensor, the sixth linear Hall sensor and the seventh linear Hall sensor obtain the original three-phase Hall signals after collecting the magnetic pole signals of the single-pole magnetic conductor assembly. The original three-phase Hall signals are the fifth detection signal, the sixth detection signal and the seventh detection signal; After performing zero-drift processing on the obtained original three-phase Hall signals, the detection signals of the d-axis and q-axis are output; Performing angle calculation on the first group of detection signals, the second group of detection signals and the corrected third group of detection signals respectively to obtain a first electrical angle value, a second electrical angle value and a third electrical angle value, specifically including: Performing A / D conversion on the first group of detection signals, the second group of detection signals and the corrected third group of detection signals to obtain a first group of voltage values, a second group of voltage values and a third group of voltage values; According to the positive and negative nature and numerical magnitude of the voltage values in the first group of voltage values, the second group of voltage values and the third group of voltage values, obtain the angle intervals where the first group of detection signals, the second group of detection signals and the corrected third group of detection signals are located; According to the angle interval, the arctangent algorithm is used for the first group of voltage values, the second group of voltage values, and the third group of voltage values to obtain the first electrical angle value, the second electrical angle value, and the third electrical angle value.

2. The magnetic ring encoder according to claim 1, characterized in that: The output signals of the first linear Hall sensor and the second linear Hall sensor have a phase difference of 90 degrees; the output signals of the third linear Hall sensor and the fourth linear Hall sensor have a phase difference of 90 degrees; the output signals of the fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor have a phase difference of 120 degrees.

3. The magnetic ring encoder according to claim 1, wherein: The first linear Hall sensor, the third linear Hall sensor, and the fifth linear Hall sensor are aligned at one end.

4. The magnetic ring encoder according to claim 1, characterized in that: The first multi-pole magnet is located between the single-pole magnetic conductor assembly and the second multi-pole magnet.

5. The magnetic ring encoder according to claim 1, characterized in that: m and n are prime numbers and mn < 23 19.

6. The magnetic ring encoder according to claim 1, wherein: The magnetization directions of the first multi-pole magnet and the second multi-pole magnet are radial or axial, and there is an angular difference in the installation positions of the starting magnetic poles of the first multi-pole magnet and the second multi-pole magnet.

7. The magnetic ring encoder according to claim 1, wherein: The magnetization direction of the single-pole ring magnet in the single-pole magnetic conductor assembly is radial or axial.

8. Detection method for absolute angle of magnetic ring encoder, characterized in that, Applied to the magnetic ring encoder according to any one of claims 1-7, the detection method includes: Obtaining a first group of detection signals, a second group of detection signals, and a corrected third group of detection signals through a first group of Hall elements, a second group of Hall elements, and a third group of Hall elements respectively; Performing angle resolution on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals respectively to obtain a first electrical angle value, a second electrical angle value, and a third electrical angle value; According to the number of magnetic poles m of the first multi-pole magnet, the number of magnetic poles n of the second multi-pole magnet, the first electrical angle value, and the second electrical angle value, obtaining a magnetic pole position characteristic value corresponding to the first multi-pole magnet; Determining the first magnetic pole interval where the first electrical angle value is currently located according to the magnetic pole position characteristic value; Determine the initial mechanical angle formed by the first multi-pole magnet and the second multi-pole magnet according to the first magnetic pole interval, the number of magnetic pole pairs m of the first multi-pole magnet, and the first electrical angle value ; Calibrating the tooth number interval where the third electrical angle value is currently located according to the initial mechanical angle; Determining the absolute angle of the magnetic ring encoder by using the determined tooth number interval, the tooth number p of the single-pole magnetic conductor assembly, and the third electrical angle value.

9. The method for detecting the absolute angle of the magnetic ring encoder according to claim 8, wherein: The first group of detection signals includes: the first detection signal and the second detection signal output by the first linear Hall sensor and the second linear Hall sensor according to the magnetic pole signals of the first multi-pole magnet; The second group of detection signals includes: the third detection signal and the fourth detection signal output by the third linear Hall sensor and the fourth linear Hall sensor according to the magnetic pole signals of the second multi-pole magnet.

10. The method for detecting the absolute angle of the magnetic ring encoder according to claim 9, characterized in that: Performing zero-drift processing on the obtained original three-phase Hall signals and then outputting the detection signals of the d-axis and q-axis, specifically including: Performing zero-drift processing on the collected original three-phase Hall signals according to the following formula (1); Outputting the third group of detection signals of the d-axis and q-axis according to the following formula (2): Formula (1) Formula (2) In the formula, , , are the original three-phase Hall signals; is the signal drift amount; , , are the three-phase Hall voltage signals after removing the drift amount; is the angle between the detected signal electrical angle of any linear Hall sensor in the third group of Hall elements and the horizontal direction, , are the output two-phase Hall voltage signals.

11. The method for detecting the absolute angle of the magnetic ring encoder according to claim 10, characterized in that: According to the number of magnetic poles m of the first multi-pole magnet, the number of magnetic poles n of the second multi-pole magnet, the first electrical angle value, and the second electrical angle value, obtaining a magnetic pole position characteristic value corresponding to the first multi-pole magnet, specifically including: Calculate the eigenvalue of the pole position according to the following formula : ， In the formula, is the first obtained electrical angle value, is the second obtained electrical angle value.

12. The method for detecting the absolute angle of the magnetic ring encoder according to claim 11, characterized in that: Determine the initial mechanical angle formed by the first multi-pole magnet and the second multi-pole magnet according to the first magnetic pole interval, the number of magnetic pole pairs m of the first multi-pole magnet, and the first electrical angle value , specifically including: Calculate the initial mechanical angle according to the following formula : ， wherein, is the first electrical angle value the number of the magnetic pole interval currently located in, .

13. The method for detecting the absolute angle of the magnetic ring encoder according to claim 12, characterized in that: Calibrate the tooth number range where the current third electrical angle value is located according to the initial mechanical angle; Then, use the determined tooth number range, the tooth number p of the single pair of pole magnetic conductor assembly, and the third electrical angle value to determine the absolute angle of the magnetic ring encoder, specifically including: According to the obtained initial mechanical angle, calibrate the tooth number range where the current third electrical angle value is located by referring to the index table; Use the determined tooth number range, the tooth number p of the single pair of pole magnetic conductor assembly, and the third electrical angle value to determine the absolute angle of the magnetic ring encoder according to the following formula: ， In the formula, is the absolute angle output by the magnetic ring encoder, is the third electrical angle value is the number of the tooth number interval currently located, .

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