CN112117079B

CN112117079B - Encoder magnet structure, encoder, motor, electrical equipment and vehicle

Info

Publication number: CN112117079B
Application number: CN201911175352.XA
Authority: CN
Inventors: 陈文镥; 孙佳男; 孔得琳; 冯同; 郝双晖
Original assignee: Kunshan Weihan Electric Drive Technology Co ltd
Current assignee: Kunshan Weihan Electric Drive Technology Co ltd
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2022-08-26
Anticipated expiration: 2039-11-26
Also published as: CN112117079A

Abstract

The application provides an encoder magnet structure, an encoder, a motor, electrical equipment and a vehicle. The encoder magnet structure, comprising: the first multi-pair of polar magnets and the second multi-pair of polar magnets are coaxially and annularly arranged; the first multi-pair of pole magnets include m pairs of poles, the second multi-pair of pole magnets include n pairs of poles, and m and n are natural numbers greater than 2 and coprime to each other. By adopting the encoder magnet structure, the problem that a single-pole magnet is easy to damage can be solved.

Description

Encoder magnet structure, encoder, motor, electrical equipment and vehicle

Technical Field

The application belongs to the technical field of encoders, and particularly relates to an encoder magnet structure, an encoder, a motor, electrical equipment and a vehicle.

Background

The angular displacement sensor widely adopted by the high-precision servo platform in the field of industrial control at present comprises a rotary transformer, a photoelectric encoder and a magnetoelectric encoder.

The magnetoelectric encoder mainly comprises a permanent magnet and a magneto-sensitive element. The magnetic sensing element can sense the space magnetic field change caused by the rotation of the permanent magnet through the Hall effect or the reluctance effect, can convert the magnetic field change into the change of a voltage signal, and can achieve the aim of detecting the angular displacement of the rotating component through a subsequent signal processing system. Compared with a rotary transformer and a photoelectric encoder, the magnetoelectric encoder has the advantages of simple structure, high temperature resistance, oil stain resistance, impact resistance, small volume, low cost and the like, and has unique advantages in the application places of miniaturization and severe environmental conditions.

The magnetoelectric encoder mainly comprises a magnetic signal generating structure and a signal processing circuit, wherein a magnetic signal generating source is called a magnet. According to the difference of the number of the magnetic poles of the magnet, the magnetic pole can be divided into a single-pole-pair magnetic pole and a multi-pole-pair magnetic pole, so that the magnetic pole can be divided into a single-pole-pair magnetic pole encoder and a single-multi-pole-pair combined type magnetic pole encoder according to the difference of the magnetic signal generating sources of the magnetic pole encoder. The combined magnetoelectric encoder is characterized in that a multi-pair-pole magnetic field signal source is added on the basis of the traditional single-pair-pole magnetoelectric encoder, and the signals of the multi-pair-pole magnets are encoded and subdivided through the signals of the single-pair-pole magnets, so that the aim of improving the resolution ratio is fulfilled.

The typical structure of a single-pole-pair magnetoelectric encoder is that four Hall elements are arranged at intervals of 90 degrees in the radial direction around a single-pole-pair magnet. When the rotating shaft drives the magnet to rotate, two points which are radially spaced by 90 degrees can respectively generate complete sine magnetic fields and cosine magnetic fields which change along with time. The magnetic field intensity is resolved into an angle of 0-360 degrees through the difference interference elimination of two radial Hall elements and the interval arc tangent algorithm and then is converted into a digital angle value of 0-216 through a software algorithm. Similarly, when a multi-antipode magnetic field signal source is added, every antipode of the multi-antipode magnet respectively generates a complete sine and cosine magnetic field at two points radially spaced by 90-degree electrical angles when the rotating shaft rotates for one circle, the mechanical angle corresponding to each antipode can be resolved into 0-360-degree electrical angles, namely 0-216 digital angle output through an arc tangent algorithm, and the period of the multi-antipode magnet signal is determined through the angle resolved by the single-antipode magnet signal, so that the purpose of continuously encoding the digital angle of the multi-antipode magnet signal is achieved. For example, the multi-pair-pole magnet is 3 pairs of poles, the mechanical angle corresponding to each pair of poles is 120 degrees, at the moment, a complete sine and cosine period can be completed by a Hall signal within the range of 120 degrees, the angle output of 0-360 degrees can be realized through software resolving, namely the mechanical angle of 0-120 degrees is expanded to the range of 0-360 degrees, the digital angle value output of 0-3 multiplied by 216 can be realized through accumulation of the signal periods of the multi-pair-pole magnet, and the resolution ratio of a single-pair-pole magnet is improved by 3 times theoretically.

A large number of experiments prove that when the number of pole pairs of the multi-pair-pole magnet is large, the period of the multi-pair-pole magnet signal is judged only by the limited digital angle range of the single-pair-pole magnet, and misjudgment of the multi-pair-pole digital angle value interval is high in probability, so that error coding of the multi-pair-pole digital angle value is realized, and the reliability and the precision of the combined magnetoelectric encoder are greatly reduced.

In addition, under the condition that the radial dimension of the motor is large and the axial dimension is small, the combined magnetoelectric encoder adopting the combination form of the single-pair pole and the multiple-pair pole can lead to the fact that the radial dimension of the magnetic pole of the single-pair pole is large and the axial dimension is small, and when the combined magnetoelectric encoder is processed and magnetized or used, the magnetic pole of the single-pair pole is easily damaged, and the processing and the application of the encoder are influenced.

In another existing multi-pole and multi-pole combined encoder, the number of the magnetic pole pairs usually differs by 1, and the initial position alignment is required during installation, so that the operation is inconvenient.

Disclosure of Invention

The application provides an encoder magnet structure, through using this application encoder magnet structure can improve combination formula magnetoelectric encoder's reliability and precision, solves the fragile problem of single to utmost point magnet, solves the inconvenient problem of installation simultaneously.

The application provides an encoder magnet structure, including: a first and a second plurality of pairs of polar magnets arranged coaxially and annularly;

wherein the first multi-pair of pole magnets comprises m pairs of poles and the second multi-pair of pole magnets comprises n pairs of poles, m and n being natural numbers greater than 2 and coprime to each other.

In some embodiments of the present application, the first plurality of pairs of pole magnets are located on an outer ring, the second plurality of pairs of pole magnets are located on an inner ring, and m is greater than n.

In some embodiments of the present application, m and n are prime numbers.

In some embodiments of the present application, the first plurality of pairs of pole magnets are arranged with a magnetization direction that coincides with a radial or axial direction of the ring.

In some embodiments of the present application, the second plurality of pairs of pole magnets are arranged with a magnetization direction that coincides with a radial or axial direction of the ring.

The magnetic structure of the encoder can solve the problem of misjudgment of a single-pair and multi-pair combined magnetoelectric encoder, and improves reliability and precision; and simultaneously, the problems of large size and easy damage of the single-pole magnet are solved.

The present application further proposes an encoder, the encoder comprising:

the encoder magnet structure as described above;

a first group of switching hall sensors disposed opposite to the first multi-pair pole magnets so as to output a first detection signal according to magnetic pole signals of the first multi-pair pole magnets;

a second group of switching hall sensors disposed opposite to the second multi-pair pole magnets so as to output a second detection signal according to magnetic pole signals of the second multi-pair pole magnets;

the two linear Hall sensors are arranged adjacent to the first multi-pair-pole magnet or the second multi-pair-pole magnet, so that the phases of output signals of the two linear Hall sensors are different by 90 degrees.

In some embodiments of the present application, the number p of the first set of switched hall sensors is equal to or greater than n, and the number q of the second set of switched hall sensors is equal to or greater than m.

In some embodiments of the present application, the first set of switched hall sensors and the second set of switched hall sensors are aligned at one end.

In some embodiments of the present application, the first set of switched hall sensors are arranged at 360/2mp spacing angles, and the second set of switched hall sensors are arranged at 360/2nq spacing angles.

According to the encoder provided by the application, one end of the magnetic pole does not need to be aligned in the installation process, so that the installation process is simplified; meanwhile, the encoder can be applied to working conditions of small axial size and large radial size, and the application range of the magnetoelectric encoder is expanded.

The application also provides a motor, which comprises the encoder.

The application also provides an electrical device comprising the aforementioned motor.

The present application further proposes a vehicle comprising the aforementioned electric machine.

Drawings

The present application is described in detail below with reference to the attached drawings. The foregoing and other aspects of the present application will become more apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings. In the drawings:

fig. 1A is a schematic structural plan view of an encoder magnet structure according to the present application.

Fig. 1B is a schematic structural perspective view of an encoder magnet structure according to the present application.

FIG. 2A is a schematic plan view of an encoder with a bi-radial arrangement of magnet structures as described herein.

Fig. 2B is a perspective view of an encoder with a magnet structure arranged in a bi-radial direction according to the present application.

FIG. 3A is a schematic plan view of an encoder with a bi-axial arrangement of magnet structures as described herein.

Fig. 3B is a perspective view of an encoder with a bi-axial arrangement of the magnet structure according to the present application.

FIG. 4A is a schematic plan view of an encoder with a magnet structure according to the present application arranged in a single radial and single axial direction.

Fig. 4B is a perspective view of a single-radial and single-axial encoder of the magnet structure according to the present application.

FIG. 5 is a sequence diagram of encoder angle calibration as described herein.

Fig. 6 is an overall operation flow diagram of the encoder according to the present application.

Detailed Description

The following detailed description of the embodiments refers to the accompanying drawings.

The embodiments/examples described herein are specific embodiments of the present application and are intended to be illustrative and exemplary of the concepts of the present application and should not be construed as limiting the embodiments of the present application and the scope of the present application. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification of the present application, and these technical solutions include technical solutions which make any obvious replacement or modification of the embodiments described herein, and all of which are within the scope of the present application.

Fig. 1A and 1B illustrate front and perspective views of an encoder magnet structure according to an example embodiment of the present application.

As shown in fig. 1A, 1B, the encoder magnet structure includes: a first and a second multi-pair of

polar magnets

11, 12 arranged coaxially and annularly in a first spatial plane. The first multi-pole magnet 11 includes m pairs of magnetic poles, and the second multi-pole magnet 12 includes n pairs of magnetic poles, where m and n are natural numbers greater than 2 and are relatively prime to each other. For example, according to some embodiments, m and n are prime numbers. As shown in fig. 1A and 1B, in the present embodiment, m is 5 and n is 3, but the present application is not limited thereto.

When encoding with encoder magnets, the motor rotor, for example, can be positioned according to the encoding result. However, if the coding has repetition, the positioning cannot be performed efficiently. In order to eliminate or reduce the repeated condition, the magnet structure with the relatively prime multi-pair poles is adopted in the application, and the repeated coding condition can be eliminated by combining the arrangement of the Hall elements, as will be described in detail later.

Further, the first multiple pairs of polar magnets 11 are located on the outer ring, the second multiple pairs of polar magnets 12 are located on the inner ring, and the number m of opposite poles of the first multiple pairs of polar magnets is greater than the number n of opposite poles of the second multiple pairs of polar magnets. This is because the diameter of the outer ring is larger than that of the inner ring, and the number of magnets of the outer ring is larger than that of the inner ring in order to make the size of the magnets uniform.

According to some embodiments, the first plurality of pairs of polar magnets 11 may be arranged with a magnetization direction coinciding with the radial or axial direction of the ring. In the embodiment shown in fig. 1A, 1B, the magnetization direction of the first multiple pairs of pole magnets 11 is set to the axial direction. The second plurality of pairs of pole magnets 12 may also be arranged with a magnetization direction that coincides with the radial or axial direction of the ring. In the embodiment shown in fig. 1A, 1B, the magnetization direction of the second multi-pair pole magnet 12 is set to the axial direction. The magnetization direction is not limited to this, and the magnetization direction of the first and second pairs of pole magnets may be set to the radial direction, the magnetization direction of the second pair of pole magnets may be set to the axial direction, or the magnetization directions of the first and second pairs of pole magnets may be set to the radial direction, as described later with reference to fig. 2A to 4B.

In the encoder magnet structure shown in fig. 1A and 1B, the first and second multiple-pole pairs 11 and 12 may be formed by adhering multiple magnetic poles, but not limited thereto. The magnet according to this application can adopt neodymium iron boron permanent magnet material to make, and a plurality of magnets can be attached on the base plate, or directly attached for example at the pivot tip. According to some embodiments, a plurality of magnets may be disposed on the support plate. The support plate may be an annular structure and a second plurality of pairs of pole magnets 12 may be disposed along a circumferential normal direction of the bore thereof. The first multi-pair pole magnet 11 is fixed to the annular surface of the support plate. The fixing means may be an adhesive bond.

Fig. 2A and 2B illustrate schematic plan and perspective views of a magnet structure dual radial arrangement encoder according to an example embodiment of the present application. The encoder comprises an encoder magnet structure as described in any of the above embodiments.

As shown in fig. 2A, 2B, the encoder includes the aforementioned encoder magnet structure of the first and second pairs of

polar magnets

11, 12. In the present embodiment, the number m of the first multiple pairs of pole magnets 11 is 5, and the number n of the second multiple pairs of pole magnets 12 is 3.

According to an example embodiment, the encoder further comprises: a first group of switching hall sensors 110 disposed adjacent to the first multi-pole magnet 11 to output a first detection signal according to a magnetic pole signal of the first multi-pole magnet 11; and a second group of switching hall sensors 120 disposed adjacent to the second multi-pair pole magnet 12 to output a second detection signal according to a magnetic pole signal of the second multi-pair pole magnet 12.

Further, the encoder also includes two linear hall sensors 130. The linear hall sensor 130 is disposed adjacent to the first or second

multi-pair pole magnet

11 or 12 such that the output signals of the two linear hall sensors 130 are 90 degrees out of phase.

According to some embodiments, the number p of the first set of switched hall sensors 110 is equal to or greater than n, and the number q of the second set of switched hall sensors 120 is equal to or greater than m.

According to some embodiments, in the encoder structure described above, the first set of switched hall sensors 110 and the second set of switched hall sensors 120 are aligned at one end.

The first set of switched hall sensors 110 are arranged at 360/2mp intervals and the second set of switched hall sensors are arranged at 360/2nq intervals. See the detailed description below with specific regard to the arrangement of the hall element.

Fig. 3A and 3B show a schematic plan view and a schematic perspective view of a magnet structure two-axis arrangement encoder according to the present exemplary embodiment. As shown in fig. 3A and 3B, the magnetization directions of the first and second pairs of

polar magnets

11 and 12 are both axially arranged, and the other arrangements are the same as the embodiment in fig. 2A and 2B, and are not described again here.

Fig. 4A and 4B show a plan view and a perspective view of a single-axial single-radial-arrangement encoder of a magnet structure according to the present exemplary embodiment. As shown in fig. 4A and 4B, the magnetization directions of the first multi-pole magnet pair 11 are arranged in a radial direction, the magnetization directions of the second multi-pole magnet pair 12 are arranged in an axial direction, and the other arrangements are the same as the embodiments in fig. 2A and 2B, and are not described again here.

Sufficient conditions for setting the switching hall element are described below. In the encoder structure, each magnetic pole can only judge the N and S of the magnetic pole by using the switch Hall. For each pair of magnetic poles, the plurality of switch Hall devices can realize the angular subdivision in the period of the pair of magnetic poles. But cannot identify pairs of pole periods. The angular subdivision of 180 DEG/k can be realized by using k equally spaced distributed switch Hall devices. Therefore, the position sections of the magnetic poles can be divided by the hall switch, and the sections of the magnetic poles can be judged according to the difference of the relative positions of the magnetic poles between two magnetic pole poles.

As mentioned above, m, n are the numbers of the first and second pairs of magnetic pole magnets, respectively, and m>n is the same as the formula (I). Assuming that the total angle of the two sets of magnets is l, l _m 、l _n Respectively the angle of each antipole of the two groups of magnets, the common divisor of m and n is a, m ₁ 、m ₂ The result is obtained by dividing m and n by the common divisor a. Then:

l _m ×m×2＝l _n ×n×2＝l

l _m ×m ₁ ×2＝l _n ×n ₁ ×2＝l ₁

l＝al ₁

that is, the same relative position occurs a times in the two sets of magnetic poles, which results in a repeated position characteristic a times. Only when a is 1, i.e. the two pole pairs are relatively prime, the repetitive position feature cannot occur.

When m and n are coprime, l _m 、l _n There is also no common divisor, there is l between each pole (non-counter pole) of two sets of magnetic poles _n -l _m The x-th antipole will appear x (l) due to the angle difference _n -l _m ) The positional deviation of (2). Since there is no common divisor, when x ≠ n or x ≠ m, no positional deviation of an integer number of poles occurs. The relative position between each pole of the two sets of poles is not the same.

At this time, if the relative position between each pole of the two sets of magnetic poles can be identified and expressed in a specific manner, the discrimination of the magnetic pole period can be achieved.

The discrimination of the pole periods by the arrangement of the switched hall elements is described below. The switching hall element has the following operating characteristics:

each pair of magnetic poles can only use the switch Hall to judge the N and S of the magnetic poles, the switch Hall outputs 1 (set high) when approaching the N pole and outputs 0 (set low) when approaching the S pole;

for each pair of magnetic poles, the plurality of switch Hall devices can realize the angular subdivision in the period of the pair of magnetic poles. In a magnetic pole period, the angular subdivision of 180 degrees/k can be realized by using k equally-spaced distributed switch Hall devices;

the multiple switched hall effect does not allow discrimination of the period of the poles for only one set of poles.

Based on the above analysis, a plurality of switches, holrs, can be used to encode the region angles within a pair of pole periods to have unique encoded values. This encoded value will repeat for subsequent pole segments. And because the relative position between each magnetic pole in two groups of magnets is different, two codes of two groups of magnets in the same angle area can be combined to form a code value which does not repeatedly appear in the circumferential range. Each period of the magnetic pole can be judged according to the coding value as long as the range of the angle area is reasonably set.

Therefore, two groups of switch Hall devices which are arranged according to a certain rule can be arranged around two groups of coprime magnetic steels according to different relative positions to identify each period of the magnetic poles.

Assuming that m-n is d, a feasible scheme obtained by research is that the switch hall is arranged in one magnetic pole period of two groups of magnets at equal intervals, two switch hall in the initial position are aligned at one end, the two groups of switch hall are arranged in the same direction, and the angle area to be identified is the minimum relative position deviation between the magnetic poles

According to the working characteristics of the Hall switch, m poles are required

And each switch Hall needs m switches for n antipodes.

Therefore, as long as the switching hall elements can be arranged according to the number requirement and arranged around the magnetic poles at equal intervals, non-repeated coding can be realized, namely, each magnetic pole period can be identified.

Taking five pairs of poles and three pairs of poles as examples, the arrangement scheme of the switch hall and the working characteristics of the switch hall given by the analysis are combined. A truth table for determining the pole period can be obtained as shown below. The table is given according to the scheme of initial position alignment of two groups of magnets, and when the initial positions are not aligned, a truth table can be obtained in the same way.

TABLE 1 truth table of five and three pairs of poles under full condition

A method of reducing the number of hall elements using the truth table is described below. In the above sufficient condition for setting the switching hall element, the switching hall element may be too many, which is not favorable for practical use. Besides the above sufficient conditions, a scheme with fewer switch hall numbers can be obtained by adjusting the number and the angle of the switch hall in a truth table manner.

A truth table is prepared for the encoder in the present exemplary embodiment in which the number of the first multiple pairs of poles is 5 and the number of the second multiple pairs of poles is 3, and the magnetic pole periods are divided. The method comprises the following steps:

step 1: two columns of 1, 0 of equal length are established, as shown in table 1 for the first column of five pairs of poles and the first column of three pairs of poles. Where 1 represents the N pole of each pair of poles and 0 represents the S pole of each pair of poles. As can be seen from table 1, the first columns of the two pairs of poles show 5 and 31, 0 changes, i.e. five and three pairs of poles are represented. Since the five-pair and three-pair magnetic poles are 360 ° in an actual product, the purpose of setting equal-length series can be expressed as this.

The column length shown in table 2 is 30, i.e., 3 × 5 × N ═ 30, where N ═ 2. Where 3 × 5 is to ensure that the sequence is equal in length, and the following multiplication by N is to arrange the sequence in step 2. At this time, the magnetic poles are divided into 30 sections in this manner, and the angle occupied by each section is 12 °. Each interval corresponds to a row in the truth table.

Step 2: according to the selected magnetic pole pairs, the number of the selected switch Hall sensors is preliminarily determined, such as 3 and 5 pairs of poles, and two groups of 3 switch Hall sensors are respectively used. For the magnetic poles, if the Hall difference of the two switches is a certain angle, the phase difference generated by detection is reflected as a certain interval number from a truth table. As shown in table 2 for five antipodes, the second and third columns differ from the first column by one and two intervals, respectively. And taking the first column with five pairs of poles as a reference position, the difference between the two switch hall sensors and the first switch hall sensor is 12 degrees and 24 degrees of an actual angle respectively, namely the detected phase difference is 12 degrees and 24 degrees.

Adjusting the angle of the hall sensor in this way results in a truth table as shown in table 2.

And 3, step 3: considering that in the magnetic pole installation process, in order to simplify the magnetic pole installation process, two magnetic poles are not aligned at zero point, so that a true value for one of the opposite poles needs to be shifted by the interval number corresponding to the angle as a whole.

And 4, step 4: after the truth table is made, it needs to be checked. The binary code has the problem of repeatedly defining intervals, namely whether one binary code simultaneously defines a plurality of magnetic poles. If not, the truth table may be used. If present, this can be solved in three ways: firstly, under the condition that the quantity of Hall elements is not changed, the interval number of intervals among the Hall elements of the switch is adjusted; secondly, further refining the angle, namely subdividing the angle by increasing the N of 3 multiplied by 5 multiplied by N in the step 1; thirdly, the number of the Hall sensors is increased, namely the number of bits of binary codes is increased.

After the truth table is manufactured, the switch Hall element is installed according to the result of the truth table, and in the working process of the encoder, the truth table is searched according to the binary code output by the switch Hall element to judge the magnetic pole section where the magnetic pole is located. The simplest truth table of five pairs of poles and three pairs of poles is given in table 2.

TABLE 2 truth table of five pairs of poles and three pairs of poles

According to the simplest truth table in table 2, the number of the switching hall elements on the five pairs of magnetic poles and the three pairs of magnetic poles can be set to 3, so that the non-repetitive coding requirement can be met.

A single-cycle angle solution method according to an example embodiment is described below. The method may be applied to an encoder according to an embodiment of the present application.

After sine and cosine signals are obtained by applying the linear Hall element, a digital voltage value with a certain digit can be obtained through A/D conversion in the circuit. The digital voltage value at this time has a certain relationship with the measurement angle value of the encoder, but is not the measurement angle value of the encoder, and the angle calculation is also required.

For the signal of each antipole magnet, the position of the two Hall elements on the space is different by 90 degrees, so that the sine and cosine signals output by the two Hall signals are different by 90 degrees in phase, at the moment, the signal with the phase ahead is regarded as a sine signal, and the signal with the phase lagging is regarded as a cosine signal. And removing the cosine signal by using the sine signal to obtain the tangent value of the point signal, and then performing arc tangent treatment on the tangent value to obtain the actual angle value of the point position. However, if the angle is directly solved by the above method, since the interval of the tangent function is [ -90 °, 90 ° ], which will cause the interval error of the angle solution, it is necessary to solve the problem by the interval method.

The 360 degrees of each magnetic pole are divided into 8 equal-length sections at intervals of 45 degrees, and the position of the Hall signal at the moment is judged by judging the voltage of the two linear Hall elements and judging the positive and negative of the two linear Hall elements.

The principle of implementing the angle calculation by the inter-partition arctangent algorithm is shown in table 3. Wherein, VA and VB are linear Hall detection signals with phase difference of 90 degrees.

TABLE 3 division of the Angle intervals

Through the division of the angle intervals, the conversion from the Hall acquisition signals to the digital angle signals can be realized, and the converted digital angle intervals range is [0 degrees, 360 degrees ].

The actual angle calculation method according to the example embodiment is described below. The method may be applied to an encoder according to an embodiment of the present application.

The angle of the multi-pair pole encoder obtained through angle calculation is only the angle corresponding to one pair of magnetic poles, not the absolute angle, and the absolute angle of the multi-pair pole encoder needs to be obtained through the following formula:

θ＝PN+θ ₁ /P _max

in the formula: θ — absolute angle value;

p-the angle obtained by measurement belongs to the period of the magnetic pole, and P belongs to [0, P ] _max ]，P _max The number of pole pairs of the magnetic poles;

n-angle value corresponding to each pair of magnetic poles, N being 360 °/P _max ；

θ ₁ The angle value obtained by linear Hall calculation.

N, P in the formula _max 、θ ₁ Are all known numbers after angle resolution. P can obtain the current magnetic pole period according to the truth table during angle measurement.

An angle calibration method according to an example embodiment is described below. The method may be applied to an encoder according to an embodiment of the present application.

After the angle calculation and the actual angle calculation of the encoder are completed, the magnetoelectric encoder can measure the angle. But the angular accuracy of the measurement is low. Therefore, the magnetoelectric encoder needs to be calibrated.

After the multi-pair-pole encoder realizes continuous encoding, the multi-pair-pole encoder and the high-precision photoelectric encoder simultaneously measure the angle of the rotating shaft, and the two groups of angle values are simultaneously acquired through the data acquisition system. The photoelectric encoder is used as a standard measuring instrument, and the one-to-one corresponding relation between the multi-pair-pole encoder and the photoelectric encoder can be obtained by calibrating experimental data.

The encoder calibration process is as follows:

and sequencing the multi-pair polar data and the photoelectric encoder data by taking the multi-pair polar data after continuous encoding as a reference so as to increase the sample capacity and ensure that the established corresponding relation is more accurate. The sorted results are shown in fig. 5.

For comparison, the data of the photoelectric encoder and the multi-pair polar encoder are converted into the same magnitude.

And dividing the continuously coded data of the photoelectric encoder into M intervals in a partitioned mode, and obtaining M +1 equidistant nodes.

And drawing an image by taking the multi-antipode data as an X axis and the photoelectric data as a Y axis, and compensating the data at the head node and the tail node in order to perform fitting operation. Wherein the half period before the first equidistant node is replaced by the half period before the last node minus the PN, and the half period after the last node is replaced by the half period after the first equidistant node plus the PN.

And (3) performing least square fitting on data in half intervals before and after the nodes by taking the M +1 equidistant nodes as centers. And after the fitting is finished, solving a fitting value corresponding to each node, and subtracting the multi-pair polar data corresponding to the node from the fitting value to obtain a calibrated error. The error is tabulated with the first column of the table as the node value and the second column as the error value.

After the table is manufactured, the table is placed in a storage area of a single chip microcomputer, after the multi-pair polar angle is obtained through calculation in the working process, the position of the multi-pair polar data is determined through a table looking-up mode, if the multi-pair polar angle is located on nodes, corresponding difference values are added to the multi-pair polar data, and if the multi-pair polar angle is located between the nodes, an output angle value is calculated according to linear interpolation.

The precision is greatly improved through the calibrated angle value.

An encoder work flow diagram according to an example embodiment is shown in fig. 6. As shown in fig. 6, the workflow diagram includes:

s1: collecting signals, including collecting linear Hall signals and switching Hall signals;

s2: transmitting signals, including converting the signals collected in S1 into digital voltage signals through an amplifier and an a/D converter;

s3: processing the signal, including calculating and processing the signal transmitted in S2 to obtain a final result;

s4: and outputting the measurement result.

In S3, the signal calculation and processing includes S310 single cycle angle resolution, S320 truth table determination of pole period, S330 actual angle calculation, S340 error compensation.

The use of encoders is well known to those skilled in the art and will not be described in detail herein.

It should be noted that the embodiments described above with reference to the drawings are only for illustrating the present invention and do not limit the scope of the present invention. It will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. Furthermore, unless the context indicates otherwise, words that appear in the singular include the plural and vice versa. Additionally, all or a portion of any embodiment may be utilized with all or a portion of any other embodiment, unless stated otherwise.

Claims

1. An encoder, comprising:

the encoder magnet structure comprises a first multi-pair-pole magnet and a second multi-pair-pole magnet which are coaxially and annularly arranged, the first multi-pair-pole magnet is positioned on the outer ring, the second multi-pair-pole magnet is positioned on the inner ring,

wherein the first multi-pair of pole magnets comprises m pairs of poles, the second multi-pair of pole magnets comprises n pairs of poles, m and n are natural numbers greater than 2 and are coprime to each other, m is greater than n, the first multi-pair of pole magnets are arranged such that the magnetization direction coincides with the radial or axial direction of the ring, and the second multi-pair of pole magnets are arranged such that the magnetization direction coincides with the radial or axial direction of the ring;

a first group of switching hall sensors disposed adjacent to the first multi-pair pole magnet so as to output a first detection signal according to a magnetic pole signal of the first multi-pair pole magnet;

a second group of switching hall sensors disposed adjacent to the second multi-pair pole magnets so as to output a second detection signal according to magnetic pole signals of the second multi-pair pole magnets;

two linear hall sensors, the two linear hall sensors being disposed adjacent to the first or second multi-pair of pole magnets such that phases of output signals of the two linear hall sensors differ by 90 degrees;

the number p of the first group of switch Hall sensors is equal to or larger than n, the number q of the second group of switch Hall sensors is equal to or larger than m, and the first group of switch Hall sensors and the second group of switch Hall sensors are respectively arranged around the corresponding magnetic poles at equal intervals.

2. The encoder of claim 1, wherein the first set of switched hall sensors and the second set of switched hall sensors are aligned at one end.

3. The encoder of claim 1, wherein the first set of switched hall sensors are arranged at 360/2mp intervals and the second set of switched hall sensors are arranged at 360/2nq intervals.

4. An electric machine, comprising:

an encoder according to any of claims 1-3.

5. An electrical device, comprising: the electric machine of claim 4.

6. A vehicle, characterized by comprising: the electric machine of claim 4.