Three-ring structure magnetoelectric encoder and magnetoelectric encoder absolute angle detection method

Abstract

The present invention relates to the field of encoder technology, and more specifically to a three-ring structure magnetoelectric encoder and a method for detecting the absolute angle of a magnetoelectric encoder. The three-ring structure magnetoelectric encoder includes a second multi-pole magnet, a first multi-pole magnet, and a third multi-pole magnet coaxially arranged, as well as a first group of Hall elements, a second group of Hall elements, and a third group of Hall elements; wherein the first group of Hall elements is arranged adjacent to the first multi-pole magnet and outputs a first group of detection signals based on the magnetic pole signals of the first multi-pole magnet; the second group of Hall elements is arranged adjacent to the second multi-pole magnet and outputs a second group of detection signals based on the magnetic pole signals of the second multi-pole magnet; and the third group of Hall elements is arranged adjacent to the third multi-pole magnet and outputs a corrected third group of detection signals based on the magnetic pole signals of the third multi-pole magnet. The present invention calibrates the actual angle of the third multi-pole magnet by obtaining a mechanical angle with a certain accuracy, thereby significantly improving the measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of encoders, and in particular to a three-ring structure magnetoelectric encoder and a method for detecting the absolute angle of the magnetoelectric encoder. Background Art

[0002] Currently, the angular displacement sensors widely used in high-precision servo platforms in the industrial control field include resolvers, photoelectric encoders, and magnetoelectric encoders. Magnetoelectric encoders primarily consist of a permanent magnet and a magnetic sensor. The magnetic sensor senses the spatial magnetic field changes caused by the permanent magnet's rotational motion through the Hall effect or magnetoresistive effect, converting these magnetic field changes into voltage signals. Through subsequent signal processing, the angular displacement of the rotating component can be detected. Compared to resolvers and photoelectric encoders, magnetoelectric encoders offer advantages such as simple structure, high temperature resistance, oil and impact resistance, compact size, and low cost. These advantages make them particularly advantageous in applications requiring miniaturization and harsh environmental conditions.

[0003] A magnetoelectric encoder primarily consists of a magnetic signal generating structure and a signal processing circuit. The magnetic signal generating source is called a magnet. Depending on the number of magnetic poles, magnetoelectric encoders can be divided into single-pole and multi-pole encoders. Currently, the most commonly used multi-pole encoder uses dual multi-pole permanent magnets with mutually prime radial inner and outer ring pole pairs. The inner multi-pole permanent magnet serves as the reference pole, while the outer multi-pole permanent magnet serves as the measuring pole. The reference and measuring poles rotate coaxially, and four linear Hall elements are used to collect the raw magnetic field signal. The positional relationship between the magnetic pole and the reference pole, i.e., the magnetic pole position characteristic value, is measured to determine the current magnetic pole interval of the measuring pole. The absolute angle calculation formula is then used to obtain the absolute angle of the magnetoelectric encoder.

[0004] In practical applications, if higher-precision magnetoelectric encoders are required, such as when used on large-diameter motor shafts or large-diameter hollow shafts, the number of magnetic pole pairs must be increased. The greater the number of pole pairs, the higher the accuracy. However, when the number of pole pairs between the measuring and reference poles reaches a certain value, the angle measurements of the reference and measuring poles contain random errors and noise, causing the magnetic pole position eigenvalues ​​to overlap within a certain range. This results in the failure of the magnetic pole position eigenvalues ​​to obtain the absolute angle of the magnetoelectric encoder, making it impossible to achieve the higher accuracy required by the encoder. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a three-ring structure magnetoelectric encoder, aiming to overcome the problem that in the actual application of the radial inner and outer ring multi-pole magnetoelectric encoder, the increase in the number of pole pairs leads to the failure of the magnetic pole position characteristic value, thereby failing to achieve the higher accuracy requirements of the encoder.

[0006] Another object of the present invention is to provide a method for detecting the absolute angle of a magnetoelectric encoder, aiming to solve the problem that the accuracy of the existing magnetoelectric encoder cannot be improved due to the increase in the number of pole pairs.

[0007] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0008] The three-ring structure magnetoelectric encoder provided by the present invention comprises:

[0009] A second multi-pole magnet, a first multi-pole magnet, and a third multi-pole magnet coaxially arranged, wherein the first multi-pole magnet includes m pairs of poles and 3≤m<23, the second multi-pole magnet includes n pairs of poles and 3≤n<23, m is greater than n and is a natural number that is mutually prime, and the third multi-pole magnet includes p pairs of poles and p≥100;

[0010] A first set of Hall elements, including a first linear Hall sensor and a second linear Hall sensor, is disposed adjacent to the first multi-pole magnet and outputs a first set of detection signals according to magnetic pole signals of the first multi-pole magnet;

[0011] a second set of Hall elements, including a third linear Hall sensor and a fourth linear Hall sensor, disposed adjacent to the second multi-pole magnet and outputting a second set of detection signals according to 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, is arranged adjacent to the third multi-pole magnet and outputs a modified third group of detection signals according to the magnetic pole signals of the third multi-pole magnet.

[0013] Furthermore, the output signals of the first linear Hall sensor and the second linear Hall sensor differ in phase by 90 degrees; the output signals of the third linear Hall sensor and the fourth linear Hall sensor differ in phase by 90 degrees; and the output signals of the fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor differ in phase by 120 degrees.

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

[0015] Furthermore, the first multi-pole magnet is located between the third multi-pole magnet and the second multi-pole magnet.

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

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

[0018] More preferably, the magnetization direction of the third multi-pole magnet is radial or axial.

[0019] In addition, the present invention also provides a method for detecting the absolute angle of a magnetoelectric encoder, which is applied to the magnetoelectric encoder with the three-ring structure. The detection method includes:

[0020] Obtaining 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;

[0021] Performing angle calculation 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, respectively;

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

[0023] determining, based on the magnetic pole position characteristic value, a first magnetic pole interval in which the first electrical angle value is currently located;

[0024] An initial mechanical angle θ formed by the first multi-pole magnet and the second multi-pole magnet is determined 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. _single ;

[0025] calibrating, according to the initial mechanical angle, a third magnetic pole interval in which the third electrical angle value is currently located;

[0026] The absolute angle of the magneto-electric encoder is determined using the determined third magnetic pole interval, the number p of magnetic pole pairs of the third multi-pole magnet, 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 the first linear Hall sensor and the second linear Hall sensor according to the magnetic pole signal of the first multi-pole magnet;

[0028] The second set of detection signals includes: a third detection signal and a fourth detection signal output by the third linear Hall sensor and the fourth linear Hall sensor according to the magnetic pole signal of the second multi-pole magnet;

[0029] The modified third group of detection signals includes: d-axis and q-axis detection signals 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 third multi-pole magnet.

[0030] Furthermore, the d-axis and q-axis detection signals output by the fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor according to the magnetic pole signal of the third multi-pole magnet specifically include:

[0031] The fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor acquire magnetic pole signals of the third multi-pole magnet to obtain original three-phase Hall signals, wherein the original three-phase Hall signals are the fifth detection signal, the sixth detection signal, and the seventh detection signal;

[0032] The original three-phase Hall signal is processed for zero-point drift and then the detection signals of the d-axis and q-axis are output.

[0033] Furthermore, the original three-phase Hall signal is processed for zero drift and then the d-axis and q-axis detection signals are output, specifically including:

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

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

[0036]

[0037]

[0038] Where, U1, U2, and U3 are the original three-phase Hall signals; U shift is the signal drift; U′1, U′2, and U′3 are the three-phase Hall voltage signals after removing the drift; α is the angle between the detection signal electrical angle of any linear Hall sensor in the third group of Hall elements and the horizontal direction, U d 、U q is the output two-phase Hall voltage signal.

[0039] Furthermore, performing angle calculation 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:

[0040] 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;

[0041] Obtaining the angle intervals of the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals based on the positive and negative values ​​and the magnitudes of the voltage values ​​in the first group of voltage values, the second group of voltage values, and the third group of voltage values;

[0042] According to the angle interval, an inverse tangent algorithm is used on 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.

[0043] Furthermore, according to the number m of magnetic pole pairs of the first multi-pole magnet, the number n of magnetic pole pairs 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 includes:

[0044] The magnetic pole position characteristic value λ is calculated according to the following formula:

[0045]

[0046] Where θ m is the first electrical angle value obtained, θ n is the second electrical angle value obtained.

[0047] Furthermore, an initial mechanical angle θ formed by the first multi-pole magnet and the second multi-pole magnet is determined 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. _single , specifically including:

[0048] Calculate the initial mechanical angle θ according to the following formula _single :

[0049] θ _single =N m ×360° / m+θ m / m

[0050] Where N m is the first electrical angle value θ m The current magnetic pole segment number, N m ∈[0,m-1].

[0051] Furthermore, according to the initial mechanical angle, the third magnetic pole interval in which the third electrical angle value is currently located is calibrated; and then the absolute angle of the magneto-electric encoder is determined using the determined third magnetic pole interval, the number of magnetic pole pairs p of the third multi-pole magnet, and the third electrical angle value, specifically including:

[0052] According to the obtained initial mechanical angle, the third magnetic pole interval where the third electrical angle value is currently located is calibrated by looking up the table index.

[0053] The absolute angle of the magnetoelectric encoder is determined using the determined third magnetic pole interval, the number of magnetic pole pairs p of the third multi-pole magnet, and the third electrical angle value according to the following formula:

[0054] θ=N p ×360° / p+θ p / p

[0055] Where θ is the absolute angle output by the magnetoelectric encoder, N p is the third electrical angle value θ p The current magnetic pole segment number, N p ∈[0,p-1].

[0056] The beneficial effects of the present invention are as follows: the present invention adds a multi-pole magnet axially on the basis of the original two-ring multi-pole magnet. The number of magnetic pole pairs of the multi-pole magnet is much larger than that of the two-ring magnet. The mechanical angle with a certain accuracy obtained by the original two-ring multi-pole magnet is used to calibrate the actual rotation angle of the added multi-pole magnet, thereby greatly improving the measurement accuracy of the magnetoelectric encoder and meeting the actual needs of angle detection of large-diameter shaft parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0058] Figure 1 A three-dimensional diagram of a magnetoelectric encoder with a three-ring structure according to an embodiment of the present application is shown;

[0059] Figure 2 The following is a flow chart of a method for detecting an absolute angle of a magnetoelectric encoder according to an embodiment of the present application;

[0060] Figure 3 Shown is a schematic diagram of signal detection principles of two linear Hall sensors in an embodiment of the present application;

[0061] Figure 4 A schematic diagram of detection signals of two linear Hall elements in an embodiment of the present application is shown;

[0062] Figure 5 Shown is a schematic diagram of signal detection principles of three linear Hall sensors in an embodiment of the present application;

[0063] Figure 6 Shows a schematic diagram of detection signals of three linear Hall sensors in an embodiment of the present application;

[0064] Figure 7A schematic diagram showing the principle of eliminating zero drift using three Hall signals in an embodiment of the present application is shown;

[0065] Figure 8 A schematic diagram showing the principle of synthesizing two-phase Hall signals in an embodiment of the present application is shown;

[0066] Figure 9 Show Figure 1 There is an angle difference θ between the installation positions of the starting magnetic poles of the second multi-pole magnet and the first multi-pole magnet. x Schematic diagram of;

[0067] Figure 10 A schematic diagram showing the number of magnetic pole position characteristic values ​​in an embodiment of the present application. DETAILED DESCRIPTION

[0068] Example embodiments will be described more fully below with reference to the accompanying drawings. However, the example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. These examples are provided to make the present disclosure more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. In the figures, identical reference numerals indicate identical or similar parts, and thus repeated description thereof will be omitted.

[0069] Furthermore, the described features, structures, or characteristics may 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.

[0070] 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 used only to distinguish. As used herein, the term "and / or" includes any one and all combinations of one or more of the associated listed items.

[0071] Those skilled in the art will appreciate that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the accompanying drawings are not necessarily required for implementing the present invention and therefore cannot be used to limit the scope of protection of the present invention.

[0072] In the process of actual application, the existing multi-pole magnetoelectric encoder with two rings and mutually prime pole pairs will inevitably encounter the situation of large-diameter shafts. In this case, for the two-ring multi-pole magnets mounted on the large-diameter shaft, it is necessary to increase the number of pole pairs of their own magnets accordingly. Under ideal circumstances, that is, under the condition that the two-ring multi-pole magnets have no installation errors and no noise influence, the multi-pole magnetoelectric encoder with two rings and mutually prime pole pairs can fully measure the rotation angle of large-diameter shaft parts. However, the technicians of this application found that in the process of actual application, when the number of pole pairs of the two-ring multi-pole magnets increases to a certain number, the detection signal obtained by the Hall element will be completely consistent in a certain angle range, which will cause the multi-pole magnetoelectric encoder with two rings and mutually prime pole pairs to be unable to measure the rotation angle of large-diameter shaft parts, thereby causing the measurement accuracy of the magnetoelectric encoder to fail.

[0073] To address the aforementioned issues, the present application provides a three-ring magnetoelectric encoder. This three-ring magnetoelectric encoder adds a multi-pole magnet axially to the original two-ring multi-pole magnet, with a significantly greater number of pole pairs than the two rings. The actual rotation angle of the added multi-pole magnet is calibrated using the mechanical angle obtained with a certain degree of accuracy by the original two-ring multi-pole magnet, thereby significantly improving the measurement accuracy of the magnetoelectric encoder and meeting the practical needs of angle detection for large-diameter shaft parts. The following detailed description of the technical solution of this application is provided in conjunction with the accompanying drawings.

[0074] Figure 1 A three-dimensional diagram showing the structure of a high-precision magnetoelectric encoder according to an embodiment of the present application.

[0075] like Figure 1 As shown, the present application provides a three-ring structure magnetoelectric encoder 100, comprising: a second multi-pole magnet 120, a first multi-pole magnet 110 and a third multi-pole magnet 130 coaxially arranged in a first spatial plane. The first multi-pole magnet 110 includes m pairs of poles and 3≤m<23, the second multi-pole magnet 120 includes n pairs of poles and 3≤n<23, m is greater than n and mn<23×19, and the third multi-pole magnet 130 includes p pairs of poles and p≥100. p can be 100, 200, 300, 400, 500, 600, 700, 800, or even more. The greater the number of P, the higher the accuracy of the final magnetoelectric encoder. For example, according to some embodiments, m and n are prime numbers and are mutually prime. As Figure 1 As shown, in this embodiment, m is 5, n is 3, and p is 100, but the present application is not limited thereto.

[0076] According to an exemplary embodiment of the present application, the first multi-pole magnet 110 is located between the third multi-pole magnet 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 greater than the diameter of the second multi-pole magnet 120. To make the magnets uniform in size, the number of magnetic pole pairs of the first multi-pole magnet 110 is greater than the number of magnetic pole pairs of the second multi-pole magnet 120.

[0077] In this 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 limited in order to obtain effective detection signals and avoid overlap of detection signals within a certain angle range during actual application.

[0078] According to some embodiments of the present application, the magnetization direction of the first multi-pole magnet 110 may be radial or axial. Figure 1 In the embodiment shown, the magnetization direction of the first multi-pole magnet 110 is set to be axial. The magnetization direction of the second multi-pole magnet 120 can also be radial or axial. Figure 1 In the embodiment shown, the magnetization direction of the second multi-pole magnet 120 is set to be axial. Similarly, the magnetization direction of the third multi-pole magnet 130 can also be radial or axial. Figure 1 In the embodiment shown, the magnetization direction of the third multi-pole magnet 130 is set to be axial. The present application does not impose any limitation on the magnetization direction.

[0079] The first multi-pole magnet 110, the second multi-pole magnet 120, and the third multi-pole magnet 130 can each be formed by bonding multiple magnetic pole pairs, but are not limited thereto. According to an embodiment of the present application, the magnets can be made of neodymium iron boron permanent magnet material and directly attached to the rotating shaft or fixed to the rotating shaft. When installed and fixed, the starting magnetic poles of the first multi-pole magnet 110 and the second multi-pole magnet 120 have an installation angle difference.

[0080] like Figure 1 As shown, the three-ring structure magnetoelectric encoder 100 further includes a first group of Hall elements, a second group of Hall elements and a third group of Hall elements for detecting magnetic signals generated by a multi-pole magnet.

[0081] A 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 multi-pole magnet 110 and outputs a first set of detection signals based on magnetic pole signals from the first multi-pole magnet 110. The output signals of the first linear Hall sensor 111 and the second linear Hall sensor 112 are 90 degrees out of phase with each other.

[0082] A second set of Hall elements, including a third linear Hall sensor 121 and a fourth linear Hall sensor 122, is disposed adjacent to the second multi-pole magnet 120 and outputs a second set of detection signals based on 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 are 90 degrees out of phase with each other.

[0083] A third set of Hall elements, including a fifth linear Hall sensor 131, a sixth linear Hall sensor 132, and a seventh linear Hall sensor 133, are positioned adjacent to the third multi-pole magnet 130 and output a modified third set of detection signals based on the magnetic pole signals of the third multi-pole magnet 130. The output signals of the fifth, sixth, and seventh linear Hall sensors 131, 132, and 133 are 120 degrees out of phase with each other.

[0084] According to some embodiments, in the above-mentioned 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-mentioned encoder is working, the first multi-pole magnet 110, the second multi-pole magnet 120, and the third multi-pole magnet 130 rotate together with the rotating shaft, while the three groups of Hall elements remain stationary.

[0085] Figure 2 A flow chart of the absolute angle detection method of a magnetoelectric encoder according to an embodiment of the present application is shown.

[0086] The present application also provides a method for detecting the absolute angle of the magnetoelectric encoder, such as Figure 2 As shown, including:

[0087] In step S210 , a first group of detection signals, a second group of detection signals, and a 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.

[0088] The magnetoelectric encoder provided herein includes a second multi-pole magnet 120, a first multi-pole magnet 110, and a third multi-pole magnet 130 coaxially mounted on a rotating shaft. The pole pairs of the second multi-pole magnet 120 and the first multi-pole magnet 110 are mutually prime, and the three magnet groups are isolated using isolation techniques to prevent magnetic field coupling. The magnetic field around the three multi-pole magnet groups exhibits a sinusoidal distribution in the circumferential direction.

[0089] The two linear Hall sensors in the first group of Hall elements and the second group of Hall elements corresponding to the first multi-pole magnet 110 and the second multi-pole magnet 120 are arranged at an angle of 90 degrees. Figure 3 、 4The 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 is introduced.

[0090] Figure 3 The following is a schematic diagram showing the signal detection principle of two linear Hall sensors in an embodiment of the present application.

[0091] Figure 4 A schematic diagram of detection signals of two linear Hall elements in an embodiment of the present application is shown.

[0092] As the magnet rotates one circle, the magnetic field at any point in the space where it is located changes regularly. This change can be converted into sine and cosine electrical signals using two linear Hall sensors with an electrical angle difference of 90 degrees. The frequency of the electrical signal change is the same as the frequency of the magnetic pole rotation. Figure 3 、 4 As shown, for the second multi-pole magnet 120 with three pairs of poles, each rotation of the magnet results in the third linear Hall sensor 121 and the fourth linear Hall sensor 122 detecting three cycles of sine and cosine signals, respectively, i.e., a set of detection signals. The first set of Hall elements provided on the first multi-pole magnet 110 can generate a first set of detection signals. The second set of Hall elements provided on the second multi-pole magnet 120 can generate a second set of detection signals.

[0093] In actual practice, the two-Hall arrangement is often arranged at an angle of 90° in electrical angle. However, it is difficult to eliminate errors caused by processing or assembly with the two-Hall method, and it is also difficult to suppress harmonic errors in the magnetic field. Increasing the number of Halls or arranging them symmetrically has the main effect of using symmetrical cancellation to reduce mechanical errors and offset harmonic components. To this end, the present application sets a three-Hall arrangement on the third multi-pole magnet 130, and a higher calculation accuracy can be obtained when the three Hall electrical angles are 120°.

[0094] The third set of Hall elements is arranged adjacent to the third multi-pole magnet 130, and the three linear Hall sensors are arranged at intervals of 120° electrical angle. Figure 5-8 The principle of using three linear Hall sensors to detect the magnetic signal of the third multi-pole magnet 130 is described below.

[0095] Figure 5 The following is a schematic diagram showing the signal detection principles of three linear Hall sensors in an embodiment of the present application.

[0096] Figure 6 A schematic diagram of detection signals of three linear Hall sensors in an embodiment of the present application is shown.

[0097] Figure 7 A schematic diagram showing the principle of eliminating zero drift using three Hall signals in an embodiment of the present application is shown.

[0098] Figure 8 A schematic diagram of synthesizing two-phase Hall signals in an embodiment of the present application is shown.

[0099] According to the above principle, it is easy to know that the magnetic field change can be converted into positive and cosine electrical signals by using three linear Hall sensors with an electrical angle difference of 120 degrees. Figure 5 、 6 As shown, for the third multi-pole magnet 130 with 6 pairs of poles, when the magnet rotates one circle, 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. Here, the original three-phase Hall signals are Figure 8 U1, U2, and U3 are used to represent them respectively, and U1 corresponds to the detection signal of the fifth linear Hall sensor 131; U z U3 corresponds to the detection signal of the sixth linear Hall sensor 132 ; U4 corresponds to the detection signal of the seventh linear Hall sensor 133 .

[0100] Due to the problems of Hall arrangement and mechanical assembly, the original three-phase Hall signals U1, U2, and U3 are superimposed with some error signals. d 、U q There is a high probability that the zero point will drift.

[0101] Therefore, it is necessary to process the zero drift of the original three-phase Hall signal collected, such as Figure 7 As shown, the calculation is performed according to the following formula:

[0102]

[0103] Where, U1, U2, and U3 are the original three-phase Hall signals; U shift is the signal drift; U′1, U′2, and U′3 are the three-phase Hall voltage signals after removing the drift.

[0104] Then, the three-phase Hall voltage signal with zero drift removed is synthesized into two-phase U d 、U q Signals, such as Figure 8 As shown, the following formula is used for conversion:

[0105]

[0106] Where α 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, U d 、U qThe output two-phase Hall voltage signal is the modified third set of detection signals.

[0107] At this point, the third set of detection signals with a corrected two-phase phase difference of 90° can be approximately regarded as the sine and cosine detection signals collected by two linear Hall sensors. For the convenience of subsequent text description, this application approximately regards the third set of Hall elements as two linear Hall sensors arranged at an angle of 90° in electrical angle.

[0108] 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°.

[0109] In step S220, 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 a first electrical angle value, a second electrical angle value, and a third electrical angle value, respectively.

[0110] After obtaining sine and cosine signals using a linear Hall sensor, a specific number of digital voltage values ​​can be obtained through an A / D conversion circuit. Specifically, the first, second, or third set of voltage values ​​are obtained by performing A / D conversion on the first, second, or modified third set of detection signals, respectively. While these digital voltage values ​​have a certain correlation with the encoder's measured angle values, they are not the encoder's actual angle values ​​and require further angle resolution.

[0111] For each set of magnetic pole signals, the spatial positions of the two linear Hall sensors differ by 90°, causing their sine and cosine signals to be 90° out of phase. The phase-advancing signal can be considered a sine signal, while the phase-lagging signal can be considered a cosine signal. Dividing the sine signal by the cosine signal yields the tangent value of the signal at that point. Applying the inverse tangent to this tangent yields the electrical angle at that point.

[0112] Because the tangent function spans the range [-90°, 90°], directly calculating the angle using the above process will result in an incorrect interval. Therefore, a method for segmenting the data into intervals is required to address this issue. Specifically, the electrical angle interval within which the first, second, or corrected third set of detection signals reside is determined based on the positive and negative values ​​and magnitudes of the voltages in the first, second, or third set of voltage values.

[0113] Taking the angle calculation of a set of magnetic poles as an example, the 360° angle can be divided into eight equal-length intervals at 45° intervals. The position of the Hall signal at that point is determined by evaluating the magnitude and positive / negative value of the voltage detected by two linear Hall elements. The implementation principle of the interval-divided inverse tangent algorithm is shown in Table 1. Here, VA and VB are linear Hall detection signals with a 90° phase difference.

[0114] Table 1 Division of angle intervals

[0115]

[0116] By dividing the above angle intervals, the signal collected by the Hall element can be converted into an angle signal, and the range of the converted electrical angle signal is [0°, 360°].

[0117] For the magnetoelectric encoder of the present application, the angular ranges within which the first, second, and third sets of voltage values ​​are located can be determined based on the positive and negative values ​​and magnitudes of the voltages in the first, second, and third sets of voltage values. Based on these angular ranges, the first, second, and third electrical angle values ​​can be obtained by applying the inverse tangent algorithm to the first, second, or third sets of voltage values ​​as shown in Table 1. The electrical angle values ​​here refer to the electrical angle values ​​for a single pair of magnetic pole cycles, referred to as single-cycle electrical angle values.

[0118] During angle measurement, three sets of multi-pole pairs rotate simultaneously with the shaft, while the linear Hall element remains stationary, receiving the changing magnetic field signals generated by the rotating magnetic poles. The linear Hall sensor's sensing signal is processed using the aforementioned inverse tangent lookup table method to obtain the electrical angle value for a single magnetic pole pair cycle of the measured magnet. Once the electrical angle value for a single cycle is determined, the magnetic pole interval within which this single cycle's electrical angle value falls is then determined, ultimately yielding the absolute angle value detected by the magnetoelectric encoder.

[0119] In the absolute angle detection method for a magnetoelectric encoder provided in this application, an initial mechanical angle with a certain degree of accuracy is first determined based on the two sets of detection signals from the second multi-pole pair magnet 120 and the first multi-pole pair magnet 110. This initial mechanical angle is then used to calibrate the specific magnetic pole interval of the third multi-pole pair magnet 130 within which the single-cycle electrical angle value of the third multi-pole pair magnet 130 currently resides. Finally, the mechanical angle of the magnetoelectric encoder is calculated using a formula for calculating the mechanical angle value. The mechanical angle mentioned in this application is also referred to as the absolute angle.

[0120] Next, this application will describe in detail how to obtain an initial mechanical angle with a certain accuracy.

[0121] In this application, the initial mechanical angle can be calculated according to the following formula:

[0122] θ _single =N m ×360° / m+θ m / m Formula (3) Where, N m ∈[0, m-1] or

[0123] θ _single =(N m -1)×360° / m+θ m / m Formula (4) Where, N m ∈[1,m]

[0124] Where θ _single is the initial mechanical angle, θ m is the single-cycle electrical angle value measured by the linear Hall sensor on the first multi-pole magnet 110, N m is θ m m is the number of magnetic pole pairs of the first multi-pole magnet 110. Here, θ m Also called the first electrical angle value.

[0125] for Figure 1 In the encoder shown in FIG, there is an angle difference θ between the starting magnetic pole installation positions of the second multi-pole magnet 120 and the first multi-pole magnet 110. x ,like Figure 9 As shown, the initial mechanical angle can also be expressed as:

[0126] θ _single =N n ×360° / n+θ n / n+θ x Formula (5) Where, N n ∈[0, n-1] or

[0127] θ _single =(N n -1)×360° / n+θ n / n+θ x Formula (6) Where, N n ∈[1,n]

[0128] Where θ _single is the initial mechanical angle, θ n is the single-cycle electrical angle value measured by the linear Hall sensor on the second multi-pole magnet 120, N n is θ n n is the number of magnetic pole pairs of the second multi-pole magnet 120. n Also called the second electrical angle value.

[0129] 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) to (6).

[0130] In step S230 , a first magnetic pole interval corresponding to the first electrical angle value is determined according to the number m of magnetic pole pairs of the first multi-pole magnet 110 , the number n of magnetic pole pairs of the second multi-pole magnet 120 , the first electrical angle value, and the second electrical angle value.

[0131] When the linear Hall sensor on the first multi-pole pair magnet 110 measures two identical single-cycle electrical angle values, the corresponding two single-cycle electrical angle values ​​measured by the linear Hall sensor on the second multi-pole pair magnet 120 are different. This can distinguish the magnetic pole pair number, i.e., the magnetic pole interval, in which the single-cycle electrical angle of the first multi-pole pair magnet 110 is currently located.

[0132] For the magnetoelectric encoder magnet structure provided in this application, if the greatest common divisor of the number of magnetic pole pairs m and n of the first multi-pole magnet 110 and the second multi-pole magnet 120 is 1, i.e., they are mutually prime, then each pole pair of the first multi-pole magnet 110 has a corresponding, non-overlapping magnetic pole portion of the second multi-pole magnet 120. This is demonstrated by contradiction below.

[0133] Assume there is a positive integer N m1 , N m2 , N n1 , N n2 , N m1 ≠N m2 , so that the following formula holds:

[0134] (N m1 -1)×360° / m+θ m / m=(N n1 -1)×360° / n+θ n / n+θ x (N m2 -1)×360° / m+θ m / m=(N n2 -1)×360° / n+θ n / n+θ x Formula (7)

[0135] Among them, θ m is the single-cycle electrical angle value measured by the linear Hall sensor on the first multi-pole magnet 110, N m1 , N m2 ∈[1, m], θ is measured twice m The corresponding first magnetic pole interval; θ nis the single-cycle electrical angle value measured by the linear Hall sensor on the second multi-pole magnet 120, N n1 , N n2 ∈[1, n], θ is measured twice n The corresponding second magnetic pole interval; θ x It is the installation angle difference between the starting points of a pair of magnetic poles in the two sets of magnets.

[0136] Subtracting the two equations in formula (7) yields:

[0137]

[0138] Since m and n are mutually prime, and N m1 -N m2 ∈[1, m-1], so formula (8) is never true, that is, formula (7) is never true.

[0139] From formula (8), we can further obtain:

[0140]

[0141] Formula (9) for any different N m and its corresponding N n , are not true. That is, for different magnetic pole pairs in the first multi-pole magnet 110 and corresponding magnetic pole pairs in the second multi-pole magnet 120, formula (9) does not hold. This proves 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 electrical 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.

[0142] Combining formula (3) and formula (5), we can get:

[0143]

[0144] It can be seen that the value on the right side of the expression is a single-cycle electrical angle value that does not include the current sampling point. The value depends only on the magnetic pole interval numbers of the second multi-pole magnet 120 and the first multi-pole magnet 110. m , N n ) is fixed, its value is a constant, which is the characteristic value of the mapping interval number group.

[0145] set up It is defined as the magnetic pole position characteristic value. As can be seen from formula (10), when the number of magnetic pole pairs of the first multi-pole magnet 110 and the second multi-pole magnet 120 remains unchanged, the magnetic pole position characteristic value remains unchanged. When at least one of them changes, the magnetic pole position characteristic value will also change. Otherwise, equation (9) holds, which contradicts the premise that the magnetic pole pairs are mutually prime. Therefore, the magnetic pole interval where the current electrical angle is located can be determined by calculating the magnetic pole position characteristic value.

[0146] When θ x ≠0, that is, when the starting points of a pair of magnetic poles of the second multi-pole magnet 120 and the first multi-pole magnet 110 do not coincide, and cannot be made to coincide by changing the coordinate starting points, the magnetic pole position characteristic value λ has m+n different values. Figure 10 shown.

[0147] Figure 10 A schematic diagram showing the number of magnetic pole position characteristic values ​​in an embodiment of the present application.

[0148] Figure 10 In the figure, the first multi-pole magnet 110 has m pairs of poles, where m is 5, so five boxes are used to represent the planar expansion of the five pairs of poles. The second multi-pole magnet 120 has n pairs of poles, where n is 3. After planar expansion, it is equivalent to introducing three vertical lines in the five boxes. Since θx≠0, there are a total of m+n+1 lines divided 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. Similarly, 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.

[0149] After the second multi-pole magnet 120 and the first multi-pole magnet 110 are installed, θ x The value of has been determined, then the m+n different values ​​are already constant. According to the number of magnetic pole pairs m of the first multi-pole magnet 110 and the number of magnetic 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 magnetic pole position characteristic value corresponding to the first multi-pole magnet 110 can be determined. Figure 9 Taking the magnetoelectric encoder structure shown in as an example, θ x =40°, and the rotation direction of the magnet is clockwise, the magnetic pole position characteristic values ​​obtained by calibration and the corresponding magnetic pole intervals on the first multi-pole magnet 110 are shown in Table 2.

[0150] Table 2 Correspondence between λ value and magnetic pole interval of the first multi-pole magnet

[0151]

[0152] The corresponding relationship between λ and the magnetic pole interval in Table 2 can be used to identify the magnetic pole position, that is, the first magnetic pole interval where the first electrical angle value is currently located can be calculated based on the magnetic pole position characteristic value.

[0153] In step S240, an initial mechanical angle θ formed by the first multi-pole magnet 110 and the second multi-pole magnet 120 is determined based on the first magnetic pole interval, the number m of magnetic pole pairs of the first multi-pole magnet 110, and the first electrical angle value. _single .

[0154] After determining the first electrical angle value and the first magnetic pole interval 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).

[0155] In step S250, the third magnetic pole interval where the third electrical angle value currently resides is calibrated according to the initial mechanical angle.

[0156] On the premise of obtaining the initial mechanical angle, the initial mechanical angle can be used to calibrate the third magnetic pole interval where the third electrical angle value of the third multi-pole magnet 130 currently lies.

[0157] In this application, the third magnetic pole section N p The corresponding relationship with the initial mechanical angle is as follows:

[0158] N p =INT(θ _single ×p / 360), N p ∈[0, p-1]

[0159] Therefore, an index table is created to map the initial mechanical angle to the third magnetic pole segment. The first column of the index table contains the initial mechanical angle value, and the second column contains the segment number of the third magnetic pole segment corresponding to the initial mechanical angle. Since the initial mechanical angle is an absolute angle with a range of [0°, 360°], the first row of the first column contains the number 0, and the last row of the first column contains the number 360.

[0160] For example, assuming that the number of pole pairs of the outer ring multi-pole magnet is 5, the initial mechanical angle obtained by calibration and the corresponding third magnetic pole interval are shown in Table 3.

[0161] Table 3 Index table of the relationship between the initial mechanical angle and the magnetic pole interval in the third multi-pole magnet

[0162] <![CDATA[Initial mechanical angle θ _single > Magnetic pole interval P 0 0 1 0 2 0 3 … … 3 358 3 359 4 360 4

[0163] Therefore, once the initial mechanical angle is determined, the value of the third magnetic pole interval can be obtained by looking up the table. However, it should be noted that when creating the table, the number of rows in the initial mechanical angle column must be set to be significantly larger than the number of magnetic pole pairs of the third multi-pole magnet 130 to significantly improve the accuracy of the magnetoelectric encoder.

[0164] For example, in Table 3, the number of rows in the column of initial mechanical angle is 360, while the number of magnetic pole pairs of the third multi-pole magnet 130 is only 5, which meets the requirement of being much larger than the number of magnetic pole pairs of the third multi-pole magnet 130 .

[0165] Assuming the third multi-pole magnet 130 has 360 magnetic pole pairs, 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 magnetic pole section of the third multi-pole magnet 130. Similarly, the number of rows in the initial mechanical angle column can be set to 3600, so that each 0.1 degree of the initial mechanical angle corresponds to a magnetic pole section of the third multi-pole magnet 130. This improves the accuracy of the magnetoelectric encoder by a factor of 10. Accordingly, the accuracy can be improved by a factor of 20, 30, or even 100 times or more. This is why the number of rows is much larger than the number of magnetic pole pairs.

[0166] In step S260, the absolute angle of the magneto-electric encoder is determined using the determined third magnetic pole interval, the number p of magnetic pole pairs of the third multi-pole magnet 130, and the third electrical angle value according to the following formula:

[0167] θ=N p ×360° / p+θ p / p

[0168] Where θ is the absolute angle output by the magnetoelectric encoder, N p is the third electrical angle value θ p The current magnetic pole segment number, N p ∈[0,p-1].

[0169] Finally, it should be noted that the above 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 aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for detecting the absolute angle of a magnetoelectric encoder, applied to a three-ring structure magnetoelectric encoder, is characterized in that: The three-ring structure magnetoelectric encoder includes: A second multi-pole magnet, a first multi-pole magnet, and a third multi-pole magnet are coaxially arranged, wherein the first multi-pole magnet includes m pairs of poles and 3≤m<23, the second multi-pole magnet includes n pairs of poles and 3≤n<23, m is greater than n, and m and n are prime numbers that are mutually prime and mn<23 19. The third multi-pole magnet includes p pairs of magnetic poles and p ≥ 100; A first set of Hall elements, including a first linear Hall sensor and a second linear Hall sensor, is disposed adjacent to the first multi-pole magnet and outputs a first set of detection signals according to magnetic pole signals of the first multi-pole magnet; a second set of Hall elements, including a third linear Hall sensor and a fourth linear Hall sensor, disposed adjacent to the second multi-pole magnet and outputting a second set of detection signals according to magnetic pole signals of the second multi-pole magnet; a third set of Hall elements, including a fifth linear Hall sensor, a sixth linear Hall sensor, and a seventh linear Hall sensor, disposed adjacent to the third multi-pole magnet and outputting a modified third set of detection signals based on magnetic pole signals of the third multi-pole magnet; The absolute angle detection method of the magnetoelectric encoder includes: Obtaining 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; Performing angle calculation 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, respectively; Obtaining a magnetic pole position characteristic value corresponding to the first multi-pole magnet according to the number m of magnetic pole pairs of the first multi-pole magnet, the number n of magnetic pole pairs of the second multi-pole magnet, the first electrical angle value, and the second electrical angle value; determining, based on the magnetic pole position characteristic value, a first magnetic pole interval in which the first electrical angle value is currently located; An initial mechanical angle formed by the first multi-pole magnet and the second multi-pole magnet is determined 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. ; calibrating, according to the initial mechanical angle, a third magnetic pole interval in which the third electrical angle value is currently located; The absolute angle of the magneto-electric encoder is determined using the determined third magnetic pole interval, the number p of magnetic pole pairs of the third multi-pole magnet, and the third electrical angle value.

2. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 1, wherein: The output signals of the first linear Hall sensor and the second linear Hall sensor differ in phase by 90 degrees; the output signals of the third linear Hall sensor and the fourth linear Hall sensor differ in phase by 90 degrees; the output signals of the fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor differ in phase by 120 degrees.

3. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 1, wherein: The first linear Hall sensor is aligned with the third linear Hall sensor and the fifth linear Hall sensor at one end.

4. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 1, wherein: The first multi-pole magnet is located between the third multi-pole magnet and the second multi-pole magnet.

5. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 1, wherein: The magnetization directions of the first multi-pole pair magnet and the second multi-pole pair magnet are radial or axial, and there is an angular difference between the installation positions of the starting magnetic poles of the first multi-pole pair magnet and the second multi-pole pair magnet.

6. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 1, wherein: The magnetization direction of the third multi-pole magnet is radial or axial.

7. The method for detecting the absolute angle of a magnetoelectric encoder according to any one of claims 1 to 6, characterized in that: The first set of detection signals includes: a first detection signal and a second detection signal output by the first linear Hall sensor and the second linear Hall sensor according to the magnetic pole signal of the first multi-pole magnet; The second set of detection signals includes: a third detection signal and a fourth detection signal output by the third linear Hall sensor and the fourth linear Hall sensor according to the magnetic pole signal of the second multi-pole magnet; The modified third group of detection signals includes: d-axis and q-axis detection signals 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 third multi-pole magnet.

8. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 7, wherein: The detection signals of the d-axis and q-axis outputted by the fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor according to the magnetic pole signal of the third multi-pole magnet specifically include: The fifth linear Hall sensor, the sixth linear Hall sensor, and the seventh linear Hall sensor acquire magnetic pole signals of the third multi-pole magnet to obtain original three-phase Hall signals, wherein the original three-phase Hall signals are the fifth detection signal, the sixth detection signal, and the seventh detection signal; The original three-phase Hall signal is processed for zero-point drift and then the detection signals of the d-axis and q-axis are output.

9. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 8, wherein: After the original three-phase Hall signal is processed for zero drift, the d-axis and q-axis detection signals are output, specifically including: The collected original three-phase Hall signal is processed for zero drift according to the following formula (1); The third set of detection signals of the d-axis and q-axis are output according to the following formula (2): ， ， Where, 、 、 is the original three-phase Hall signal; is the signal drift; 、 、 is the three-phase Hall voltage signal after removing the drift; 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, 、 is the output two-phase Hall voltage signal.

10. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 9, wherein: Performing angle calculations on the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals to obtain first electrical angle values, second electrical angle values, and third electrical angle values, respectively, specifically includes: 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; Obtaining the angle intervals of the first group of detection signals, the second group of detection signals, and the corrected third group of detection signals based on the positive and negative values ​​and the magnitudes of the voltage values ​​in the first group of voltage values, the second group of voltage values, and the third group of voltage values; According to the angle interval, an inverse tangent algorithm is used on 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.

11. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 10, wherein: Obtaining a magnetic pole position characteristic value corresponding to the first multi-pole magnet according to the number m of magnetic pole pairs of the first multi-pole magnet, the number n of magnetic pole pairs of the second multi-pole magnet, the first electrical angle value, and the second electrical angle value, specifically includes: The magnetic pole position characteristic value is calculated according to the following formula : ， Where, is the first electrical angle value obtained, is the second electrical angle value obtained.

12. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 11, wherein: An initial mechanical angle formed by the first multi-pole magnet and the second multi-pole magnet is determined 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. , specifically including: Calculate the initial mechanical angle according to the following formula : ， Where, The first electrical angle value The current magnetic pole segment number, .

13. The method for detecting the absolute angle of a magnetoelectric encoder according to claim 12, wherein: Calibrate the third magnetic pole interval where the third electrical angle value is currently located according to the initial mechanical angle; and then determine the absolute angle of the magnetoelectric encoder using the determined third magnetic pole interval, the number of magnetic pole pairs p of the third multi-pole magnet, and the third electrical angle value, specifically including: According to the obtained initial mechanical angle, the third magnetic pole interval where the third electrical angle value is currently located is calibrated by looking up the index table; The absolute angle of the magnetoelectric encoder is determined using the determined third magnetic pole interval, the number of magnetic pole pairs p of the third multi-pole magnet, and the third electrical angle value according to the following formula: ， Where, is the absolute angle output by the magnetic encoder, The third electrical angle value The current magnetic pole segment number, .

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