Magnetoelectric encoder and method for detecting absolute angle of magnetoelectric encoder

Abstract

The application relates to the technical field of encoders, in particular to a magneto-electric encoder and a method for detecting the absolute angle of the magneto-electric encoder. The magneto-electric encoder comprises a second plurality of pairs of pole magnets, a first plurality of pairs of pole magnets, a single pair of pole magnet conductor combination assembly and a first group of Hall elements, a second group of Hall elements and a third group of Hall elements; the single pair of pole magnet conductor combination assembly has a tooth-shaped part and a smooth part, the first group of Hall elements and the second group of Hall elements are arranged adjacent to the first plurality of pairs of pole magnets and the second plurality of pairs of pole magnets respectively, the third group of Hall elements is arranged between the tooth-shaped part and the smooth part, and the three groups of Hall elements output corresponding detection signals according to the magnetic pole signals of the corresponding magnets. The application calibrates the rotation angle of the outermost ring magnet by acquiring a mechanical angle with certain precision, thereby greatly improving the measurement precision, and can also meet the actual needs of angle detection of large-diameter shaft parts.

Description

Technical Field

[0001] This invention relates to the field of encoder technology, specifically to a magnetoelectric encoder and a method for detecting the absolute angle of a magnetoelectric encoder. Background Technology

[0002] Magnetoelectric encoders have advantages such as simple structure, high temperature resistance, oil resistance, impact resistance, small size, and low cost, and have unique advantages in applications requiring miniaturization and in harsh environments.

[0003] A magneto-electric encoder mainly consists of two parts: a magnetic signal generating structure and a signal processing circuit. The source of the magnetic signal is called a magnet. Based on the number of poles in the magnet, magneto-electric encoders can be divided into single-pole magneto-electric encoders and multi-pole magneto-electric encoders. Currently, commonly used multi-pole magneto-electric encoders employ a dual multi-pole permanent magnet with coprime inner and outer ring pole pairs. The inner ring multi-pole permanent magnet serves as the reference pole, and the outer ring multi-pole permanent magnet serves as the measuring pole. By using four linear Hall elements to collect the original magnetic field signal through the coaxially rotating reference and measuring poles, the positional relationship between the measuring and reference poles—that is, the pole position characteristic value—is used to determine the current pole interval of the measuring pole. Then, the absolute angle of the magneto-electric encoder can be obtained using the absolute angle calculation formula.

[0004] In practical applications, when higher precision magnetoelectric encoders are required, such as for use on large-diameter motor shafts or large-diameter hollow shafts, it is necessary to increase the number of pole pairs of the magnet. The more pole pairs, the higher the precision. However, if hundreds of pole pairs are bonded together to form a multi-pole magnet, not only is it difficult to manufacture and bond the pole pairs, but the thickness of the pole pairs will also be drastically reduced to less than 1 mm. This causes the multi-pole magnet to be fragile and easily broken during the bonding process, thus preventing a significant increase in the number of pole pairs and limiting the measurement accuracy. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a magneto-electric encoder that overcomes the defects of magneto-electric encoders, which are difficult to manufacture and bond to form magnets due to the increased number of magnetic pole pairs as the accuracy of the encoder increases.

[0006] Another objective of this invention is to provide a method for detecting the absolute angle of a magnetoelectric encoder, which aims to solve the problem that the accuracy of a magnetoelectric encoder cannot be improved despite a significant increase in the number of magnetic pole pairs of multi-pole magnets.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0008] The magneto-electric encoder provided by this invention includes:

[0009] A combination of a second multi-pole magnet, a first multi-pole magnet, and a single-pole magnetic conductor arranged coaxially and radially in a ring configuration, wherein 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, where m is greater than n and is a coprime natural number, and the single-pole magnetic conductor assembly includes a first annular magnetic conductor, a single-pole annular magnet, and a second annular magnetic conductor arranged coaxially and radially in close contact, wherein the first annular magnetic conductor has a toothed portion on its outer circumference, and the second annular magnetic conductor has a smooth portion completely opposite to the toothed portion, the toothed portion and the smooth portion forming an annular opening region. Under this structure, the single-pole magnetic conductor assembly achieves a generally closed shape in its radial cross-section, wherein the opening direction of the opening region is consistent with the axial direction of the single-pole annular magnet, and p teeth are opened 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, is arranged adjacent to the first multiple pairs of pole magnets and outputs a first group of detection signals based on the magnetic pole signals of the first multiple pairs of pole magnets.

[0011] The second group of Hall elements, including the third linear Hall sensor and the fourth linear Hall sensor, is arranged adjacent to the second multiple pairs of pole magnets and outputs the second group of detection signals according to the magnetic pole signals of the second multiple pairs of pole magnets.

[0012] The third group of Hall elements includes a fifth linear Hall sensor, a sixth linear Hall sensor, and a seventh linear Hall sensor, and is disposed between the toothed portion and the smooth portion, and outputs a corrected third group of detection signals based on the magnetic pole signals of the single-pair magnetic conductor assembly.

[0013] Furthermore, the output signals of the first and second linear Hall sensors are 90 degrees out of phase; the output signals of the third and fourth linear Hall sensors are 90 degrees out of phase; and the output signals of the fifth, sixth, and seventh linear Hall sensors are 120 degrees out of phase.

[0014] Furthermore, the first linear Hall sensor, the third linear Hall sensor, and the fifth linear Hall sensor are aligned at one end.

[0015] Furthermore, the single-pair magnetic conductor assembly is located in the outermost ring, the second multi-pair magnetic conductor is located in the innermost ring, and the first multi-pair magnetic conductor is located between the single-pair magnetic conductor assembly and the second multi-pair magnetic conductor.

[0016] Preferably, m and n are prime numbers and mn < 23. 19.

[0017] More preferably, the magnetization directions of the first and second pairs of magnetic poles are radial or axial, and there is an angular difference between the initial magnetic pole installation positions of the first and second pairs of magnetic poles.

[0018] Even more preferably, the magnetization direction of the single-pole annular magnet in the single-pole magnetic conductor assembly is radial or axial.

[0019] Furthermore, the present invention also provides a method for detecting the absolute angle of a magnetoelectric encoder, applied to the aforementioned three-ring structure magnetoelectric encoder, the detection method comprising:

[0020] The first group of detection signals, the second group of detection signals, and the corrected third group of detection signals are obtained by the first group of Hall elements, the second group of Hall elements, and the third group of Hall elements, respectively.

[0021] Angle calculations are performed on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals to obtain the first electrical angle value, the second electrical angle value, and the third electrical angle value, respectively.

[0022] Based on the number of magnetic pole pairs m of the first multi-pole magnet, the number of magnetic pole pairs n of the second multi-pole magnet, the first electrical angle value, and the second electrical angle value, obtain the magnetic pole position characteristic value corresponding to the first multi-pole magnet;

[0023] Based on the magnetic pole position characteristic value, the first magnetic pole interval where the first electrical angle value is currently located is determined;

[0024] The initial mechanical angle formed by the first and second pairs of pole magnets is determined based on the first magnetic pole region, the number of pole pairs m of the first multi-pole magnet, and the first electrical angle value. ;

[0025] Based on the initial mechanical angle, the tooth count range in which the third electrical angle value currently falls is calibrated;

[0026] The absolute angle of the magneto-electric encoder is determined by using the defined tooth count range, the tooth count p of the single pair of pole conductor magnet assembly, and the third electrical angle value.

[0027] Furthermore, 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 based on the magnetic pole signals of the first multiple pairs of pole magnets;

[0028] 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 based on the magnetic pole signals of the second multi-pair magnet;

[0029] The modified third set of detection signals includes: d-axis and q-axis detection signals output by the fifth, sixth, and seventh linear Hall sensors based on the magnetic pole signals of the single-pair magnetic conductor assembly.

[0030] Furthermore, the d-axis and q-axis detection signals output by the fifth, sixth, and seventh linear Hall sensors based on the magnetic pole signals of the single-pair magnetic conductor assembly specifically include:

[0031] The fifth, sixth, and seventh linear Hall sensors acquire the magnetic pole signals of the single-pair magnetic conductor assembly to obtain the original three-phase Hall signals, which are the fifth detection signal, the sixth detection signal, and the seventh detection signal.

[0032] After zero-point drift processing of the obtained raw three-phase Hall signals, the detection signals of the d-axis and q-axis are output.

[0033] Furthermore, after zero-point drift processing of the obtained raw three-phase Hall signals, the d-axis and q-axis detection signals are output, specifically including:

[0034] The original three-phase Hall signal is processed for zero-point drift according to the following formula (1);

[0035] The third set of detection signals for the d-axis and q-axis is output according to the following formula (2):

[0036] ,

[0037] ,

[0038] In the formula, , , This is the original three-phase Hall signal; This represents the signal drift amount. , , The three-phase Hall voltage signal after removing drift; Let be 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 is the two-phase Hall voltage signal.

[0039] Furthermore, angle calculations are performed on the first set of detection signals, the second set of detection signals, and the corrected third set of detection signals to obtain the first electrical angle value, the second electrical angle value, and the third electrical angle value, specifically including:

[0040] The first group of detection signals, the second group of detection signals, and the corrected third group of detection signals are converted by A / D to obtain the first group of voltage values, the second group of voltage values, and the third group of voltage values;

[0041] Based on the sign and magnitude of the voltage values ​​in the first, second, and third sets of voltage values, the angle ranges of the first, second, and corrected third sets of detection signals are obtained.

[0042] Based on the angle range, the first electrical angle value, the second electrical angle value, and the third electrical angle value are obtained by using the arctangent algorithm on the first group of voltage values, the second group of voltage values, and the third group of voltage values.

[0043] Furthermore, based on 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, magnetic pole position characteristic values ​​corresponding to the first multi-pole magnet are obtained, specifically including:

[0044] Calculate the characteristic value of magnetic pole position using the following formula. :

[0045] ,

[0046] In the formula, To obtain the first electrical angle value, This is the second electrical angle value obtained.

[0047] Furthermore, based on the first magnetic pole interval, the number of magnetic 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. Specifically, it includes:

[0048] Calculate the initial machine angle using the following formula. :

[0049] ,

[0050] In the formula, The first electrical angle value The current magnetic pole zone number. .

[0051] Furthermore, based on the initial mechanical angle, the tooth count range in which the third electrical angle value currently lies is calibrated; then, using the determined tooth count range, the tooth count p of the single-pair pole conductor magnet assembly, and the third electrical angle value, the absolute angle of the magneto-electric encoder is determined, specifically including:

[0052] Based on the initial mechanical angle obtained, the tooth count range where the third electrical angle value currently falls can be determined by referring to the table index;

[0053] The absolute angle of the magneto-electric encoder is determined using the defined tooth count range, the tooth count p of the single-pole magnetic conductor assembly, and the third electrical angle value, according to the following formula:

[0054] ,

[0055] In the formula, This is the absolute angle output by the magneto-electric encoder. The third electrical angle value The current tooth count range number. .

[0056] The beneficial effects of this invention are as follows: In this invention, the outer surface of the first annular magnetic conductor in the single-pole magnetic conductor assembly is configured as a toothed portion, and a smooth portion completely opposite to the toothed portion is provided on the second annular magnetic conductor, with an opening between them. When the single-pole magnetic conductor assembly rotates coaxially for one revolution, the number of cycles in the detection signal collected by the Hall element corresponds one-to-one with the number of teeth in the toothed portion. That is, a detection signal containing p cycles will be obtained from a toothed portion with p teeth, which perfectly matches the detection signal collected by the Hall element from a multi-pole magnetic conductor with p pole pairs. Therefore, the single-pole magnetic conductor assembly can be considered equivalent to a multi-pole magnetic conductor with p pole pairs.

[0057] Building upon this, the increased number of pole pairs leads to difficulties in fabricating and bonding the pole pairs in multi-pole magnets. This invention, employing a single-pole magnetic conductor assembly, perfectly avoids this drawback. Machining easily creates a toothed portion with p teeth on the first annular magnetic conductor, thus significantly increasing the number of pole pairs in multi-pole magnets. This substantially improves the encoder's measurement accuracy and also meets the practical needs of angle detection for large-diameter shaft parts. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 A cross-sectional view of the magneto-electric encoder structure according to an embodiment of this application is shown;

[0060] Figure 2 This paper shows a cross-sectional perspective view of the structure of the magneto-electric encoder according to an embodiment of this application;

[0061] Figure 3This diagram illustrates a flowchart of an absolute angle detection method for a magnetoelectric encoder according to an embodiment of this application.

[0062] Figure 4 This invention illustrates the signal detection principle of two linear Hall sensors in an embodiment of this application.

[0063] Figure 5 This illustration shows a schematic diagram of two linear Hall elements detecting signals in an embodiment of this application.

[0064] Figure 6 This invention illustrates the signal detection principle of three linear Hall sensors in an embodiment of this application.

[0065] Figure 7 This illustration shows a schematic diagram of the signals detected by three linear Hall sensors in an embodiment of this application.

[0066] Figure 8 This diagram illustrates the principle of eliminating zero-point drift using three Hall signals in an embodiment of this application.

[0067] Figure 9 A schematic diagram illustrating the principle of synthesizing two-phase Hall signals in an embodiment of this application is shown;

[0068] Figure 10 Show Figure 1-2 There is an angular difference between the initial magnetic pole installation positions of the second multi-pole magnet and the first multi-pole magnet. A schematic diagram;

[0069] Figure 11 This diagram illustrates the number of magnetic pole position feature values ​​in an embodiment of this application. Detailed Implementation

[0070] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided to make the invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0071] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of the invention.

[0072] It should be understood that while the terms first, second, third, etc., may be used in this document to describe various components, these components should not be limited by these terms. These terms are used only for distinction. As used herein, the term "and / or" includes any and all combinations of any one or more of the listed items.

[0073] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams illustrating exemplary embodiments. The modules or processes shown in the drawings are not necessarily essential for implementing the present invention and therefore should not be used to limit the scope of protection of the present invention.

[0074] In practical applications, existing multi-pole magneto-electric encoders with coprime inner and outer ring pole pairs inevitably encounter situations involving large-diameter shafts. In such cases, the number of pole pairs of the inner and outer ring magnets mounted on the large-diameter shaft must be increased accordingly. Ideally, assuming no installation errors or noise affecting the inner and outer ring magnets, the multi-pole magneto-electric encoder with coprime inner and outer ring pole pairs can accurately measure the rotation angle of large-diameter shaft parts. However, those skilled in the art have discovered that in practical applications, when the number of pole pairs of the inner and outer ring magnets increases to a certain extent, the detection signal obtained by the Hall element becomes completely consistent within a certain angle range. This causes the multi-pole magneto-electric encoder with coprime inner and outer ring pole pairs to fail to measure the rotation angle of large-diameter shaft parts, thus rendering the encoder inaccurate.

[0075] In theory, by adding a large number of pole pairs to the outermost ring of existing inner and outer ring multi-pole magnets, the actual rotation angle of the encoder can be obtained, thus meeting the detection requirements of large-diameter shaft workpieces.

[0076] However, a significant increase in the number of magnet pole pairs would result in a sharp reduction in the thickness of the pole pairs to within 1 mm. Furthermore, it would require bonding hundreds of pole pairs together to form a magnet. Firstly, the process of manufacturing the pole pairs would be difficult to achieve, and the bonding process would also be extremely challenging. In the end, the resulting multi-pole magnet would be fragile and easily broken, making it impossible to achieve a significant increase in the number of pole pairs of the multi-pole magnet, thus limiting the measurement accuracy.

[0077] To address the aforementioned problems, this invention provides a magnetoelectric encoder comprising a single-pole magnetic conductor assembly. In this invention, the outer surface of the first annular magnetic conductor in the single-pole magnetic conductor assembly is configured as a toothed portion, and a smooth portion, completely opposite to the toothed portion, is provided on the second annular magnetic conductor, with an opening maintained between them. When the single-pole magnetic conductor assembly rotates coaxially for one revolution, the number of cycles in the detection signal acquired by the Hall element corresponds one-to-one with the number of teeth in the toothed portion; that is, a toothed portion with p teeth will obtain a detection signal containing p cycles, which perfectly matches the detection signal acquired by a multi-pole magnetic conductor with p pole pairs using a Hall element. Therefore, the single-pole magnetic conductor assembly can be considered equivalent to a multi-pole magnetic conductor with p pole pairs.

[0078] Furthermore, the single-pole magnetic conductor assembly of this invention perfectly avoids the defects of difficult processing and bonding. By using machining, a toothed portion with p teeth can be easily machined on the first annular magnetic conductor, thus achieving a significant increase in the number of pole pairs of the multi-pole magnetic conductor, thereby greatly improving the measurement accuracy of the encoder, and also being suitable for meeting the actual needs of angle detection of large-diameter shaft parts.

[0079] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0080] Figure 1 A cross-sectional view of the magneto-electric encoder structure according to an embodiment of this application is shown.

[0081] Figure 2 A cross-sectional perspective view of the magneto-electric encoder structure according to an embodiment of this application is shown.

[0082] like Figure 1 , Figure 2 As shown, this application provides a magneto-electric encoder 100, comprising: a second multi-pole magnet 120, a first multi-pole magnet 110, and a single-pole magnetic conductor assembly 130, all arranged coaxially and radially in a first spatial plane. The single-pole magnetic conductor assembly 130 includes a first annular magnetic conductor 135, a single-pole annular magnet 134, and a second annular magnetic conductor 136, all coaxially and radially tightly fitted together. The first annular magnetic conductor 135 has a toothed portion on its outer circumference, and the second annular magnetic conductor 136 has a smooth portion completely opposite to the toothed portion. The toothed portion and the smooth portion form an annular opening region. Under this structure, the single-pole magnetic conductor assembly 130 achieves a generally closed shape in its radial cross-section. The opening direction of the opening region is consistent with the axial direction of the single-pole annular magnet 134, and p teeth are formed on its toothed portion, where p ≥ 100.

[0083] 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, where m is greater than n and mn < 23. 19. The number of teeth p of the single-pole magnet assembly 130 can be 100, 200, 300, 400, 500, 600, 700, 800, or even more. The higher the number of p, the higher the accuracy of the final magneto-electric encoder. For example, according to some embodiments, m and n are prime numbers and coprime to each other. Figure 1 , 2 As shown in this embodiment, m is 5, n is 3, and p is 100, but this application is not limited to this.

[0084] According to an example embodiment of this application, a single-pole magnetic pair assembly 130 is located in the outermost ring, a second multi-pole magnetic pair 120 is located in the innermost ring, and a first multi-pole magnetic pair 110 is located between the single-pole magnetic pair assembly 130 and the second multi-pole magnetic pair 120. For ease of description, the outer ring, middle ring, and inner ring are respectively referred to as the single-pole magnetic pair assembly 130, the first multi-pole magnetic pair 110, and the second multi-pole magnetic pair 120. The number of pole pairs m of the first multi-pole magnetic pair 110 is greater than the number of pole pairs n of the second multi-pole magnetic pair 120. This is because the diameter of the middle ring is larger than the diameter of the inner ring, and to ensure uniform magnet size, the number of pole pairs in the middle ring magnet is greater than the number of pole pairs in the inner ring magnet.

[0085] This application specifies the number of pole pairs m of the intermediate ring and the number of pole pairs n of the inner ring in order to obtain an effective detection signal in practical applications and avoid the detection signals from overlapping within a certain angle range.

[0086] According to some embodiments of this application, the magnetization direction of the first multi-pole magnet 110 can be radial or axial. Figure 1 , 2 In the illustrated embodiment, the magnetization direction of the first pair of pole magnets 110 is set to axial. The magnetization direction of the second pair of pole magnets 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 magnet assembly 130 can also be radial or axial. Figure 1 , 2 In the illustrated embodiment, the magnetization direction of the single-pole toroidal magnet 134 is set to the axial direction. This application does not impose any limitation on the magnetization direction.

[0087] Both the first multi-pole magnet 110 and the second multi-pole magnet 120 can be formed by bonding multiple magnetic pole pairs, but are not limited thereto. According to embodiments of this application, the magnets can be made of neodymium iron boron permanent magnet material, and multiple magnets can be attached to a substrate or directly attached to the end of a rotating shaft. According to some embodiments, multiple magnets can be disposed on a support plate 140. The support plate 140 can be an annular structure, and the second multi-pole magnet 120, the first multi-pole magnet 110, and the single-pole magnetic conductor assembly 130 can be sequentially disposed along the circumferential normal direction of its inner hole. The fixing method can be adhesive bonding, and during installation, there is an angular difference in the initial magnetic poles of the first multi-pole magnet 110 and the second multi-pole magnet 120.

[0088] like Figure 1 , 2 As shown, the magneto-electric encoder 100 also includes a first group of Hall elements, a second group of Hall elements and a third group of Hall elements, used to detect magnetic signals generated by multiple pairs of pole magnets.

[0089] The first set of Hall elements, including a first linear Hall sensor 111 and a second linear Hall sensor 112, is disposed adjacent to the first plurality of pole magnets 110 and outputs a first set of detection signals based on the magnetic pole signals of the first plurality of pole magnets 110. The output signals of the first linear Hall sensor 111 and the second linear Hall sensor 112 are 90 degrees out of phase.

[0090] The second set of Hall elements, including a third linear Hall sensor 121 and a fourth linear Hall sensor 122, is arranged adjacent to the second multi-pair magnet 120 and outputs a second set of detection signals based on the magnetic pole signals of the second multi-pair magnet 120. The output signals of the third linear Hall sensor 121 and the fourth linear Hall sensor 122 are 90 degrees out of phase.

[0091] 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, is disposed between the toothed portion and the smooth portion, and outputs a corrected third group of detection signals based on the magnetic pole signals of the single-pair magnetic conductor assembly 130. The output signals of the fifth linear Hall sensor 131, the sixth linear Hall sensor 132, and the seventh linear Hall sensor 133 are 120 degrees out of phase.

[0092] It is important to note here that after the third set of Hall elements rotates once around the axis of the single-pole magnetic conductor assembly 130, it will collect three types of raw detection signals. The number of cycles in each raw detection signal is exactly the same as the number of teeth in the toothed portion of the first annular magnetic conductor 135. That is, the number of teeth p in the toothed portion matches the number of cycles in the detection signal. Therefore, the single-pole magnetic conductor assembly 130 with p teeth can be considered as a multi-pole magnet with p pole pairs.

[0093] Based on the tooth structure, we know that each tooth has a tooth tip and a tooth recess. The distance between the tooth tip, the tooth recess, and the smooth part can reflect the change in magnetic field strength. That is, according to the characteristics of magnetic field strength, when the distance between the tooth tip and the smooth part is less than the distance between the tooth recess and the smooth part, the magnetic field strength between the tooth tip and the smooth part will be greater than the magnetic field strength between the tooth recess and the smooth part.

[0094] According to some embodiments, in the encoder structure described above, 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 encoder is in operation, the first multi-pole magnet 110, the second multi-pole magnet 120, and the single-pole magnetic conductor assembly 130 rotate together with the shaft, while the three sets of Hall elements remain stationary.

[0095] Figure 3A flowchart of an absolute angle detection method for a magnetoelectric encoder according to an embodiment of this application is shown.

[0096] This application also provides a method for detecting the absolute angle of the above-mentioned magnetoelectric encoder, such as... Figure 3 As shown, it includes:

[0097] In step S310, the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals are obtained through the first group of Hall elements, the second group of Hall elements, and the third group of Hall elements, respectively.

[0098] The magneto-electric encoder provided in this application includes three sets of multi-pole magnets: an inner ring, a middle ring, and an outer ring. The number of pole pairs of the inner ring magnets and the middle ring magnets are coprime. The three sets of magnets are coaxially mounted on a rotating shaft and isolated to prevent magnetic field coupling. The magnetic field around the three sets of multi-pole magnets exhibits a sinusoidal distribution in the circumferential direction.

[0099] The first group of Hall elements and the two linear Hall sensors in the second group of Hall elements, which are respectively set to correspond to multiple pairs of pole magnets in the middle ring and inner ring, are arranged at an angle of 90° electrical angle. The following is in conjunction with... Figure 4 , 5 This paper introduces the principle of using two linear Hall sensors to detect the magnetic signal of the inner or middle ring magnet.

[0100] Figure 4 The diagram illustrates the signal detection principle of two linear Hall sensors in an embodiment of this application.

[0101] Figure 5 This diagram illustrates the detection signals of two linear Hall elements in an embodiment of this application.

[0102] As a magnet rotates one revolution along its axis, the magnetic field at any point in space changes systematically. This change can be converted into sine and cosine electrical signals using two linear Hall sensors with an electrical angle difference of 90°. The frequency of these signals is the same as the frequency of the magnetic pole rotation. For example... Figure 4 , 5 As shown, for an inner ring magnet with three pole pairs, each rotation of the magnet results in three cycles of sine and cosine signals detected by linear Hall sensors A and B, i.e., one set of detection signals. The first set of detection signals can be obtained through the first set of Hall elements set in the middle ring. The second set of detection signals can be obtained through the second set of Hall elements set in the inner ring.

[0103] In practice, two Hall effect sensors are often arranged at an angle of 90°. However, this method struggles to eliminate errors caused by machining or assembly, and it also fails to suppress harmonic errors present in the magnetic field. Increasing the number of Hall effect sensors or symmetrically arranging them primarily reduces mechanical errors through symmetrical cancellation, while also offsetting harmonic components. Therefore, this application employs a three-Hall effect sensor arrangement between the toothed portion and the smooth portion of the outer ring, achieving high calculation accuracy when the electrical angle of the three Hall effect sensors is 120°.

[0104] The third group of Hall elements is placed between the toothed section and the smooth section, and the three linear Hall sensors are arranged at intervals of 120° electrical angle. The following section combines... Figure 6-9 This paper introduces the principle of using three linear Hall effect sensors to detect magnetic signals from multiple pairs of pole magnets in the outer ring.

[0105] Figure 6 The diagram illustrates the signal detection principle of three linear Hall sensors in an embodiment of this application.

[0106] Figure 7 This diagram illustrates the signal detection of three linear Hall sensors in an embodiment of this application.

[0107] Figure 8 This diagram illustrates the principle of eliminating zero-point drift using three Hall signals in an embodiment of this application.

[0108] Figure 9 The schematic diagram of synthesizing two-phase Hall signals in the embodiments of this application is shown.

[0109] Based on the above principle, it is easy to see that this magnetic field change can also be converted into sine and cosine electrical signals using three linear Hall sensors with electrical angles differing by 120°. For example... Figure 6 , 7 As shown, for a multi-pole magnet with six pairs of poles on the outer ring, when the magnet rotates one revolution, linear Hall sensors 1, 2, and 3 detect six cycles of sine and cosine signals, i.e., the original three-phase Hall signals. In other words, the fifth linear Hall sensor 131, the sixth linear Hall sensor 132, and the seventh linear Hall sensor 133 of this application correspond to... Figure 7 Linear Hall sensors 1, 2, and 3 are used in this system.

[0110] Due to issues such as Hall effect placement and mechanical assembly, the original three-phase Hall signal... , , Some error signals were superimposed to synthesize the components of the 90° phase difference between the two phases. , At that time, there is a high probability that the zero point will drift.

[0111] Therefore, it is necessary to perform zero-point drift processing on the acquired raw three-phase Hall signals, such as... Figure 8 As shown, the specific calculation is performed according to the following formula:

[0112]

[0113] In the formula, , , This is the original three-phase Hall signal; This represents the signal drift amount. , , This is the three-phase Hall voltage signal after removing the drift.

[0114] Then, the three-phase Hall voltage signals, after removing zero-point drift, are synthesized into two phases with a 90° phase difference. , Signals, such as Figure 9 As shown, the conversion is performed using the following formula:

[0115]

[0116] In the formula, Let be 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 signals are the corrected third set of detection signals.

[0117] At this point, the third set of detection signals with a corrected two-phase phase difference of 90° can be approximated as sine and cosine detection signals acquired by two linear Hall sensors. For the convenience of subsequent textual explanation, this application approximates the third set of Hall elements as two linear Hall sensors arranged at an electrical angle of 90°.

[0118] Of course, the inner and middle rings of this application can also be arranged with three Hall sensors to improve measurement accuracy, and then the above formula can be used to convert the acquired detection signal into a detection signal with a phase difference of 90° between the two phases.

[0119] In step S320, angle calculations are performed on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals to obtain the first electrical angle value, the second electrical angle value, and the third electrical angle value, respectively.

[0120] After obtaining sine and cosine signals using a linear Hall sensor, a digital voltage value with a certain number of bits can be obtained through an A / D conversion circuit. That is, the first, second, or corrected third set of detection signals are converted to digital values ​​using an A / D converter to obtain the first, second, or third set of voltage values. While the digital voltage value at this point is related to the encoder's measured angle, it is not the encoder's measured angle value and requires angle calculation.

[0121] For each pair of magnetic poles, the two linear Hall sensors are spatially 90° apart, causing their output sine and cosine signals to be 90° out of phase. The signal with the leading phase can be considered a sine signal, and the signal with the lagging phase a cosine signal. Dividing the sine signal by the cosine signal yields the tangent of the signal at that point. Then, performing an arctangent operation on this tangent yields the electrical angle value at that point.

[0122] Since the tangent function's interval is [-90°, 90°], directly calculating the angle using the above process will lead to an error in the angle calculation interval. Therefore, it is necessary to solve the interval error problem by dividing the intervals, that is, obtaining the electrical angle interval of the first group of detection signals, the second group of detection signals, or the corrected third group of detection signals based on the sign and magnitude of the voltage values ​​in the first group of voltage values, the second group of voltage values, or the corrected third group of voltage values.

[0123] Taking the angle calculation of a set of magnetic poles as an example, the 360° of this set of magnetic poles can be divided into 8 equal-length intervals at 45° intervals. The position of the Hall signal is determined by judging the magnitude and sign of the voltage values ​​detected by the two linear Hall elements. The implementation principle of the interval arctangent algorithm is shown in Table 1 below. Where V... A V B The signal is a linear Hall effect detection signal with a 90° phase difference.

[0124] Table 1. Division of Angle Intervals

[0125]

[0126] By dividing the angle range as described above, the signal acquired by the Hall element can be converted into an angle signal, and the converted electrical angle range is [0°, 360°].

[0127] For the magneto-electric encoder of this application, the angle range of the first, second, and corrected third detection signals can be obtained based on the sign and magnitude of the voltage values ​​in the first, second, and third sets of voltage values. According to this angle range, the first, second, and third electrical angle values ​​can be obtained by applying the arctangent algorithm to the first, second, or third sets of voltage values ​​as shown in Table 1. Here, the electrical angle value refers to the electrical angle value of a single pair of magnetic poles in a single cycle, or simply the single-cycle electrical angle value.

[0128] During angle measurement, three sets of multi-pole magnets rotate with the shaft, while the linear Hall element remains stationary to receive the changing magnetic field signal generated by the rotating poles. The induced signal from the linear Hall is processed using the arctangent lookup table method described above to obtain the electrical angle value of a single pair of magnetic poles of the measured magnet. After determining the electrical angle value of a single cycle, the magnetic pole range in which the electrical angle value of that single cycle is located is determined, and finally, the tooth count range on the single pair of pole conductor assembly 130 is determined to finally obtain the absolute angle value detected by the magneto-electric encoder.

[0129] In the absolute angle detection method for the magnetoelectric encoder provided in this application, an initial mechanical angle with a certain accuracy is first determined based on two sets of detection signals from the inner ring magnet and the intermediate ring magnet. Then, this initial mechanical angle is used to calibrate which specific tooth count interval the single-cycle electrical angle value of the outer ring magnet currently falls within. Finally, the mechanical angle of the magnetoelectric encoder is calculated using the formula for calculating the mechanical angle value. The mechanical angle mentioned in this application is also referred to as the absolute angle.

[0130] Next, this application will describe in detail how to obtain an initial mechanical angle with a certain accuracy.

[0131] In this application, the initial mechanical angle can be calculated as follows:

[0132] in, or

[0133] in,

[0134] In the formula, The initial mechanical angle, The value of the electrical angle during a single cycle is measured by the linear Hall sensor on the first multi-pole magnet 110. for The first magnetic pole region in which it is located; m is the number of magnetic pole pairs of the first multi-pole magnet 110. Here, It is also known as the first electrical angle value.

[0135] for Figure 1-2 The encoder shown has an angular difference between the initial magnetic pole positions of the inner ring magnet and the middle ring magnet. ,like Figure 10 As shown, the initial mechanical angle can also be expressed as:

[0136] in, or

[0137] in,

[0138] In the formula, The initial mechanical angle, The single-cycle electrical angle value measured by the linear Hall sensor on the second multi-pole magnet 120. for The second magnetic pole region in which it is located; n is the number of magnetic pole pairs of the second multi-pole magnet 120. It is also known as the second electrical angle value.

[0139] Therefore, once the first or second electrical angle value has been obtained, as long as the corresponding magnetic pole range is determined, the initial mechanical angle value can be calculated according to the above formulas (3) to (6).

[0140] In step S330, the first magnetic pole interval corresponding to the first electrical angle value is determined based on the number of magnetic pole pairs m of the first multi-pole magnet 110, the number of magnetic pole pairs n of the second multi-pole magnet 120, the first electrical angle value, and the second electrical angle value.

[0141] When the linear Hall sensor on the first multi-pole magnet 110 measures the same single-cycle electrical angle value twice, the corresponding single-cycle electrical angle values ​​measured by the linear Hall sensor on the second multi-pole magnet 120 are different. Thus, it is possible to distinguish the number of magnetic pole pairs, i.e., the magnetic pole interval, where the single-cycle electrical angle of the first multi-pole magnet 110 is currently located.

[0142] Regarding the magnet structure of the magneto-electric 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, i.e., coprime, each pole pair of the first multi-pole magnet 110 has a corresponding non-repeating pole portion of the second multi-pole magnet 120. This will be proven by contradiction below.

[0143] Suppose there exists a positive integer N m1 N m2 N n1 N n2 N m1 ≠N m2 This makes the following equation true:

[0144]

[0145]

[0146] in, N is the single-cycle electrical angle value measured by the linear Hall sensor on the first multi-pole magnet 110. m1 N m2 ∈[1, m], which are measured twice. The corresponding first magnetic pole region; N is the single-cycle electrical angle value measured by the linear Hall sensor on the second multi-pole magnet 120. n1 N n2 ∈[1, n], which are measured twice. The corresponding second magnetic pole region; This represents the difference in installation angle between the starting points of a pair of magnetic poles in the two sets of magnets.

[0147] Subtracting the two equations in formula (7), we get:

[0148]

[0149] Since m and n are coprime, and N m1 N m2 Since ∈[1, m-1], formula (8) is never true, that is, formula (7) is never true.

[0150] From formula (8), we can further obtain:

[0151]

[0152] Formula (9) for any distinct N m and its corresponding N n The following statements are incorrect. That is, for different magnetic pole pairs in the first multi-pole magnet 110 and the corresponding magnetic pole pairs in the second multi-pole magnet 120, formula (9) is not valid. It can be proven that when the linear Hall sensor on the first multi-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-pole magnet 120 are different. In this way, the magnetic pole interval where the first angle value is currently located can be distinguished by the positional relationship between the first multi-pole magnet 110 and the second multi-pole magnet 120.

[0153] By combining equations (3) and (5), we can obtain:

[0154]

[0155] As can be seen, the value on the right side of the expression is a single-cycle electrical angle value that does not contain the current sampling point. Its magnitude depends only on the magnetic pole interval numbers of the inner and middle loops. , When the value is fixed, its value is a constant, which is the characteristic value of the mapped interval number group.

[0156] set up This is defined as the characteristic value of the magnetic pole position. As can be seen from formula (10), the characteristic value of the magnetic pole position remains unchanged when the number of pole pairs of the first multi-pole magnet 110 and the second multi-pole magnet 120 remains constant. When at least one of them changes, the characteristic value of the magnetic pole position will also change; otherwise, equation (9) holds, contradicting the premise that the number of pole pairs is coprime. Therefore, the magnetic pole range of the current electrical angle can be determined by calculating the characteristic value of the magnetic pole position.

[0157] when When ≠0, meaning the starting points of a pair of magnetic poles in the inner and middle rings do not coincide, and cannot be made to coincide by changing the coordinate starting points, the characteristic value λ of the magnetic pole position has m+n different values. For example... Figure 11 As shown.

[0158] Figure 11 This diagram illustrates the number of magnetic pole position feature values ​​in an embodiment of this application.

[0159] Figure 11 In the diagram, the middle ring magnet has m pole pairs, where m is 5. Therefore, five boxes are used to represent the planar unfolded diagram of the five pairs of magnetic poles. The inner ring magnet has n pole pairs, where n is 3. After unfolding it in a plane, it is equivalent to introducing three vertical lines into the five boxes. Because... Since ≠0, there are a total of m+n+1 lines divided into m+n parts. That is, for encoders with 5 pairs of pole magnets and encoders with 3 pairs of pole magnets, there are 8 different values ​​for the position feature value. Similarly, for encoders with 23 pairs of pole magnets and encoders with 19 pairs of pole magnets, there are 42 different values ​​for the magnetic pole position feature value.

[0160] After the inner ring and middle ring magnets are installed... The value of is already determined, so the m+n different values ​​are fixed. Based on 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, as well as the first electrical angle value and the second electrical angle value, the characteristic values ​​of the magnetic pole positions corresponding to the first multi-pole magnet 110 can be determined. Figure 10 Taking the magneto-electric encoder structure shown as an example, When the angle is 40° and the rotation direction of the magnet is clockwise, the characteristic values ​​of the magnetic pole positions obtained by calibration and the corresponding magnetic pole intervals on the first multi-pole magnet 110 are shown in Table 2.

[0161] Table 2 shows the correspondence between λ values ​​and the magnetic pole regions of the first multi-pole magnet.

[0162]

[0163] By using the correspondence between λ and magnetic pole intervals in Table 2, the magnetic pole position can be identified. That is, based on the magnetic pole position characteristic value, the first magnetic pole interval where the first electrical angle value is currently located can be calculated.

[0164] In step S340, the initial mechanical angle formed by the first multiple pole magnets 110 and the second multiple pole magnets 120 is determined based on the first magnetic pole interval, the number of pole pairs m of the first multiple pole magnets 110, and the first electrical angle value. .

[0165] After determining the first electrical angle value and the first magnetic pole range in which 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).

[0166] In step S350, the tooth count range in which the third electrical angle value is currently located is calibrated based on the initial mechanical angle.

[0167] Once the initial mechanical angle is obtained, it can be used to determine the tooth count range where the third electrical angle value of the outer ring magnet is currently located.

[0168] In this application, the number of teeth range The following correspondence exists between the initial mechanical angle and the initial mechanical angle:

[0169]

[0170] Therefore, an index table is established to correspond to the initial machine angle and the tooth count interval. The first column of the index table is the value of the initial machine angle, and the second column is the interval number of the tooth count interval corresponding to the initial machine angle. Since the initial machine angle is an absolute angle with a value range of [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.

[0171] For example, assuming the number of teeth p of the single-pole magnetic assembly 130 is 5, the initial mechanical angles and corresponding tooth number ranges obtained through calibration are shown in Table 3.

[0172] Table 3. Index of the Relationship between Initial Mechanical Angle and Tooth Number Range in Single-Pole Magnet Assembly

[0173]

[0174] Therefore, once the initial mechanical angle is determined, the range of tooth counts can be obtained by looking up the table. However, it is important to note that when creating the table, the row number of the column for the initial mechanical angle should be set to be much larger than the number of pole pairs (i.e., the number of teeth p) of the single-pole magnetic conductor assembly 130. This will significantly improve the accuracy of the magneto-electric encoder.

[0175] For example, in Table 3, the column for initial mechanical angle has 360 rows, while the number of teeth p of the single-pole magnetic assembly 130 is only 5, which is much greater than the requirement for the number of teeth of the single-pole magnetic assembly 130.

[0176] Assuming the single-pole magnet assembly 130 has 360 teeth, the number of rows in the initial mechanical angle column can be set to 360, meaning each degree of the initial mechanical angle corresponds to a tooth count interval of the single-pole magnet assembly 130. Similarly, the number of rows in the initial mechanical angle column can be set to 3600, so every 0.1 degree of the initial mechanical angle corresponds to a tooth count interval of the single-pole magnet assembly 130, thus improving the accuracy of the magneto-electric encoder by 10 times. Correspondingly, the accuracy can also be improved by 20 times, 30 times, or even 100 times or more. This is the significance of having a much larger number of rows than the number of pole pairs.

[0177] In step S360, the absolute angle of the magneto-electric encoder is determined using the tooth count range, the tooth count p of the single-pole magnetic conductor assembly 130, and the third electrical angle value according to the following formula:

[0178]

[0179] In the formula, This is the absolute angle output by the magneto-electric encoder. The third electrical angle value The current tooth count range number. .

[0180] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magneto-electric encoder, characterized in that, include: A second multi-pole magnet, a first multi-pole magnet, and a single-pole magnetic conductor assembly are arranged in a coaxial radial sequence. The first multi-pole magnet includes m pairs of magnetic poles, where 3 ≤ m < 23. The second multi-pole magnet includes n pairs of magnetic poles, where 3 ≤ n < 23. m is greater than n and is a natural number that is coprime 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 radially tightly fitted together. The first annular magnetic conductor has a toothed portion on its outer circumference. The second annular magnetic conductor has a smooth portion that is completely opposite to the toothed portion. The toothed portion and the smooth portion form an annular opening region. The opening direction of the opening region is consistent with the axial direction of the single-pole annular magnet, and p teeth are formed on its toothed portion, where p ≥ 100. The first group of Hall elements, including a first linear Hall sensor and a second linear Hall sensor, is arranged adjacent to the first multiple pairs of pole magnets and outputs a first group of detection signals based on the magnetic pole signals of the first multiple pairs of pole magnets. The second group of Hall elements, including the third linear Hall sensor and the fourth linear Hall sensor, is arranged adjacent to the second multiple pairs of pole magnets and outputs the second group of detection signals according to the magnetic pole signals of the second multiple pairs of pole magnets. The third group of Hall elements includes a fifth linear Hall sensor, a sixth linear Hall sensor, and a seventh linear Hall sensor, and is disposed between the toothed portion and the smooth portion, and outputs a corrected third group of detection signals based on the magnetic pole signals of the single-pair magnetic conductor assembly.

2. The magnetoelectric encoder according to claim 1, characterized in that: The output signals of the first and second linear Hall sensors are 90 degrees out of phase; the output signals of the third and fourth linear Hall sensors are 90 degrees out of phase; and the output signals of the fifth, sixth, and seventh linear Hall sensors are 120 degrees out of phase.

3. The magnetoelectric encoder according to claim 1, characterized in that: The first linear Hall sensor, the third linear Hall sensor, and the fifth linear Hall sensor are aligned at one end.

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

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

6. The magneto-electric encoder according to claim 1, characterized in that: The magnetization directions of the first and second pairs of pole magnets are radial or axial, and there is an angular difference between the initial pole installation positions of the first and second pairs of pole magnets.

7. The magneto-electric encoder according to claim 1, characterized in that: The magnetization direction of the single-pole annular magnet in the single-pole magnetic conductor assembly is radial or axial.

8. A method for detecting the absolute angle of a magnetoelectric encoder, characterized in that, The detection method, applied in the magneto-electric encoder according to any one of claims 1-7, comprises: The first group of detection signals, the second group of detection signals, and the corrected third group of detection signals are obtained by the first group of Hall elements, the second group of Hall elements, and the third group of Hall elements, respectively. Angle calculations are performed on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals to obtain the first electrical angle value, the second electrical angle value, and the third electrical angle value, respectively. Based on the number of magnetic pole pairs m of the first multi-pole magnet, the number of magnetic pole pairs n of the second multi-pole magnet, the first electrical angle value, and the second electrical angle value, obtain the magnetic pole position characteristic value corresponding to the first multi-pole magnet; Based on the magnetic pole position characteristic value, the first magnetic pole interval where the first electrical angle value is currently located is determined; The initial mechanical angle formed by the first and second pairs of pole magnets is determined based on the first magnetic pole region, the number of pole pairs m of the first multi-pole magnet, and the first electrical angle value. ; Based on the initial mechanical angle, the tooth count range in which the third electrical angle value currently falls is calibrated; The absolute angle of the magneto-electric encoder is determined by using the defined tooth count range, the tooth count p of the single pair of pole conductor magnet assembly, and the third electrical angle value.

9. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 8, characterized in that: 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 based on the magnetic pole signals of the first multi-pair magnet; 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 based on the magnetic pole signals of the second multi-pair magnet; The modified third set of detection signals includes: d-axis and q-axis detection signals output by the fifth, sixth, and seventh linear Hall sensors based on the magnetic pole signals of the single-pair magnetic conductor assembly.

10. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 9, characterized in that: The fifth, sixth, and seventh linear Hall sensors output d-axis and q-axis detection signals based on the magnetic pole signals of the single-pair magnetic conductor assembly, specifically including: The fifth, sixth, and seventh linear Hall sensors acquire the magnetic pole signals of the single-pair magnetic conductor assembly to obtain the original three-phase Hall signals, which are the fifth detection signal, the sixth detection signal, and the seventh detection signal. After zero-point drift processing of the obtained raw three-phase Hall signals, the detection signals of the d-axis and q-axis are output.

11. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 10, characterized in that: After zero-point drift processing of the obtained raw three-phase Hall signals, the d-axis and q-axis detection signals are output, specifically including: The original three-phase Hall signal is processed for zero-point drift according to the following formula (1); The third set of detection signals for the d-axis and q-axis is output according to the following formula (2): ， ， In the formula, , , This is the original three-phase Hall signal; This represents the signal drift amount. , , The three-phase Hall voltage signal after removing drift; Let be 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 is the two-phase Hall voltage signal.

12. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 11, characterized in that: Angle calculations are performed on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals to obtain the first electrical angle value, the second electrical angle value, and the third electrical angle value, specifically including: The first group of detection signals, the second group of detection signals, and the corrected third group of detection signals are converted by A / D to obtain the first group of voltage values, the second group of voltage values, and the third group of voltage values; Based on the sign and magnitude of the voltage values ​​in the first, second, and third sets of voltage values, the angle ranges of the first, second, and corrected third sets of detection signals are obtained. Based on the angle range, the first electrical angle value, the second electrical angle value, and the third electrical angle value are obtained by using the arctangent algorithm on the first group of voltage values, the second group of voltage values, and the third group of voltage values.

13. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 12, characterized in that: Based on 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, the magnetic pole position characteristic value corresponding to the first multi-pole magnet is obtained, specifically including: Calculate the characteristic value of magnetic pole position using the following formula. : ， In the formula, To obtain the first electrical angle value, This is the second electrical angle value obtained.

14. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 13, characterized in that: The initial mechanical angle formed by the first and second pairs of pole magnets is determined based on the first magnetic pole region, the number of pole pairs m of the first multi-pole magnet, and the first electrical angle value. Specifically, it includes: Calculate the initial machine angle using the following formula. : ， In the formula, The first electrical angle value The current magnetic pole zone number. .

15. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 14, characterized in that: Based on the initial mechanical angle, the tooth count range in which the third electrical angle value currently falls is calibrated; Then, using the determined tooth count range, the tooth count p of the single-pole magnetic assembly, and the third electrical angle value, the absolute angle of the magneto-electric encoder is determined, specifically including: Based on the obtained initial mechanical angle, the tooth count range where the third electrical angle value currently falls can be determined by referring to the index table; The absolute angle of the magneto-electric encoder is determined using the defined tooth count range, the tooth count p of the single-pole magnetic conductor assembly, and the third electrical angle value, according to the following formula: ， In the formula, This is the absolute angle output by the magneto-electric encoder. The third electrical angle value The current tooth count range number. .

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