CN114459511B

CN114459511B - Magnetic encoder and working method thereof

Info

Publication number: CN114459511B
Application number: CN202210044045.3A
Authority: CN
Inventors: 武建峰; 钱振煌
Original assignee: Quanzhou Kuntaixin Microelectronic Technology Co ltd
Current assignee: Quanzhou Kuntaixin Microelectronic Technology Co ltd
Priority date: 2022-01-14
Filing date: 2022-01-14
Publication date: 2023-11-21
Anticipated expiration: 2042-01-14
Also published as: CN114459511A

Abstract

The invention belongs to the technical field of magnetic field detection, and mainly provides a magnetic encoder and a working method thereof, wherein a magnetic field angle detection assembly generates a magnetic field detection angle which circularly changes by 180 degrees according to the magnetic field angle change of an external magnetic field, a first vector direction of the magnetic field angle detection assembly is perpendicular to a second vector direction of the magnetic field angle detection assembly, a first magnetic field orientation sensitive module and a second magnetic field orientation sensitive module are arranged based on the first vector direction and the second vector direction, when the magnetic field direction of the external magnetic field is parallel to the first vector direction, a first magnetic field orientation signal generated by the first magnetic field orientation sensitive module is in a first level state, a second magnetic field orientation signal is in a second level state, and a data fusion module generates magnetic field angle information according to the first magnetic field orientation signal, the second magnetic field orientation signal and the magnetic field detection angle, so that the aim of expanding the detection range of the rotation angle of the external magnetic field is fulfilled, and the problem that the magnetic field rotation angle of 180 degrees is measured by an AMR sensor is solved.

Description

Magnetic encoder and working method thereof

Technical Field

The invention belongs to the technical field of magnetic field detection, and particularly relates to a magnetic encoder and a working method thereof.

Background

Position sensors are typically used to detect the position of an electric machine, in particular the position of the rotor of the electric machine. In the case of a linear motor, a position sensor detects a linear position, and in the case of a rotating motor, a position sensor detects a rotational angular position of the motor to control the rotational speed and direction of the motor, the position sensor also providing an absolute angular output relative to the mechanical position of the motor shaft for use as a position feedback to adjust the motor. Since the position sensor is used as a feedback sensor for the motor shaft position, alignment of the angular domain is required, which is called "zero angle programming".

However, the current position sensor generally generates voltages proportional to the magnetic field strength in the X-axis and Y-axis directions by the AMR sensor, and obtains an angle through digital logic operation, which has a problem that only a 180 ° rotation angle of the magnetic field can be measured.

Disclosure of Invention

The invention aims to provide a magnetic encoder and a working method thereof, which aim to solve the problem that in the current position detection mode, only 180-degree magnetic field rotation angle can be measured through an AMR sensor.

An embodiment of the present invention provides a magnetic encoder including:

a magnetic field angle detection component for generating a magnetic field detection angle cyclically changing by 180 degrees according to the magnetic field angle change of an external magnetic field, wherein the magnetic field angle detection component is provided with a first vector direction and a second vector direction, the first vector direction is perpendicular to the second vector direction, and when the magnetic field direction of the external magnetic field is parallel to the first vector direction, the magnetic field detection angle is 0 degrees or 180 degrees;

The first magnetic field azimuth sensitive module is used for generating a first magnetic field azimuth signal, the first magnetic field azimuth signal is in a first level state when the magnetic field direction of the external magnetic field is consistent with the first vector direction, and the first magnetic field azimuth signal is in a second level state when the magnetic field direction of the external magnetic field is opposite to the first vector direction;

the second magnetic field azimuth sensitive module is used for generating a second magnetic field azimuth signal, the second magnetic field azimuth signal is in the first level state when the magnetic field direction of the external magnetic field is consistent with the second vector direction, and the second magnetic field azimuth signal is in the second level state when the magnetic field direction of the external magnetic field is opposite to the second vector direction;

the data fusion module is connected with the magnetic field angle detection assembly, the first magnetic field direction sensitive module and the second magnetic field direction sensitive module and is used for generating magnetic field angle information according to the first magnetic field azimuth signal, the second magnetic field azimuth signal and the magnetic field detection angle.

In one embodiment, the magnetic field angle detection assembly includes a magnetic field angle sensing module and an arctangent processing module;

The magnetic field angle sensing module is used for generating a first differential signal and a second differential signal according to the magnetic field angle change of an external magnetic field;

the arctangent processing module is used for determining the magnetic field detection angle according to the first differential signal, the second differential signal and a preset arctangent function.

In one embodiment, the magnetic field angle sensitive module comprises a plurality of anisotropic magnetoresistors;

the anisotropic magneto resistors respectively form a first Wheatstone bridge and a second Wheatstone bridge, the first Wheatstone bridge is used for outputting a first differential signal according to the angle change of an external magnetic field, and the second Wheatstone bridge is used for outputting a second differential signal according to the angle change of the external magnetic field, wherein an included angle between the second Wheatstone bridge and the first Wheatstone bridge is 45 degrees.

In one embodiment, the arctangent processing module is specifically configured to determine the magnetic field detection angle according to the following arctangent function:

A＝(1/2)*arctan(Vx/Vy)；

wherein a is the magnetic field detection angle, vx= (vx+) - (Vx-), vy= (vy+) - (Vy-), vx+, vx-are the first line voltage and the second line voltage of the first differential signal, respectively, vy+, vy-are the first line voltage and the second line voltage of the second differential signal, respectively.

In one embodiment, the first magnetic field direction sensing module and the second magnetic field direction sensing module each include a tunnel magnetoresistance, a magnetization direction of a fixed layer of the tunnel magnetoresistance of the first magnetic field direction sensing module is consistent with the first vector direction, and a magnetization direction of a fixed layer of the tunnel magnetoresistance of the second magnetic field direction sensing module is consistent with the second vector direction.

In one embodiment, the data fusion module is specifically configured to:

when the angle A is more than or equal to 0 DEG and less than 45 DEG, determining theta=A if the second magnetic field azimuth signal is in the first level state; if the second magnetic field azimuth signal is in the second level state, determining θ=a+180°;

when the angle A is less than or equal to 45 degrees and less than 135 degrees, determining theta=A if the first magnetic field azimuth signal is in the first level state; if the first magnetic field azimuth signal is in the second level state, determining θ=a+180°;

when the angle A is more than or equal to 135 degrees and less than 180 degrees, determining theta=A if the second magnetic field azimuth signal is in the second level state; if the second magnetic field azimuth signal is in the first level state, determining θ=a+180°;

wherein A represents the magnetic field detection angle, and θ represents the rotation angle of the external magnetic field.

In one embodiment, the data fusion module is specifically configured to:

when the angle A is more than or equal to 0 degrees and less than 45 degrees, if the second magnetic field azimuth signal is in the first level state, determining that the rotation angle range of the external magnetic field is 0-45 degrees; if the second magnetic field azimuth signal is in the second level state, determining that the rotation angle range of the external magnetic field is 180-225 degrees;

when the angle A is less than or equal to 45 degrees and less than 135 degrees, if the first magnetic field azimuth signal is in the first level state, determining that the rotation angle range of the external magnetic field is 45 degrees to 135 degrees; if the first magnetic field azimuth signal is in the second level state, determining that the rotation angle range of the external magnetic field is 225-315 degrees;

when the angle A is more than or equal to 135 degrees and less than 180 degrees, if the second magnetic field azimuth signal is in the second level state, determining that the rotation angle range of the external magnetic field is 135 degrees to 180 degrees; if the second magnetic field azimuth signal is in the first level state, determining that the rotation angle range of the external magnetic field is 315-360 degrees;

wherein a represents the magnetic field detection angle.

The second aspect of the embodiment of the application also provides a working method of the magnetic encoder, which comprises the following steps:

Generating a magnetic field detection angle circularly changing by 180 degrees according to the magnetic field angle change of an external magnetic field;

generating a first magnetic field orientation signal and a second magnetic field orientation signal;

generating magnetic field angle information according to the first magnetic field azimuth signal, the second magnetic field azimuth signal and the magnetic field detection angle;

a first vector direction and a second vector direction are set, the first vector direction is perpendicular to the second vector direction, and when the magnetic field direction of an external magnetic field is parallel to the first vector direction, the magnetic field detection angle is 0 degree or 180 degrees; when the magnetic field direction of the external magnetic field is consistent with the first vector direction, the first magnetic field azimuth signal is in a first level state; when the magnetic field direction of the external magnetic field is opposite to the first vector direction, the first magnetic field azimuth signal is in a second level state; when the magnetic field direction of the external magnetic field is consistent with the second vector direction, the second magnetic field azimuth signal is in the first level state; the second magnetic field orientation signal assumes the second level state when a magnetic field direction of the external magnetic field is opposite to the second vector direction.

In one embodiment, the generating magnetic field angle information from the first magnetic field orientation signal, the second magnetic field orientation signal, and the magnetic field detection angle includes:

when 0 DEG is less than or equal to A <45 DEG, if the second magnetic field azimuth signal is in the first level state, θ=A; if the second magnetic field azimuth signal is in the second level state, θ=a+180°;

when the angle A is less than or equal to 45 degrees and less than 135 degrees, if the first magnetic field azimuth signal is in the first level state, θ=A; if the first magnetic field azimuth signal is in the second level state, θ=a+180°;

when the angle A is more than or equal to 135 degrees and less than 180 degrees, if the second magnetic field azimuth signal is in the second level state, θ=A; if the second magnetic field azimuth signal is in the first level state, θ=a+180°;

the magnetic field detection angle is A, and the rotation angle of the external magnetic field is theta.

wherein a represents the magnetic field detection angle.

The embodiment of the application provides a magnetic encoder and a working method thereof, wherein a magnetic field angle detection assembly generates a magnetic field detection angle which circularly changes by taking 180 degrees as a period according to the magnetic field angle change of an external magnetic field, the first vector direction of the magnetic field angle detection assembly is perpendicular to the second vector direction of the magnetic field angle detection assembly, when the magnetic field direction of the external magnetic field is parallel to the first vector direction, the magnetic field detection angle is 0 degree or 180 degrees, a first magnetic field azimuth signal generated by a first magnetic field azimuth sensitive module is in a first level state, and when the magnetic field direction of the external magnetic field is opposite to the first vector direction, the first magnetic field azimuth signal is in a second level state; when the magnetic field direction of the external magnetic field is consistent with the second vector direction, the second magnetic field azimuth signal is in a first level state, and when the magnetic field direction of the external magnetic field is opposite to the second vector direction, the second magnetic field azimuth signal is in a second level state, and the data fusion module can determine the range of the rotation angle of the external magnetic field or a corresponding rotation angle calculation formula according to the first magnetic field azimuth signal and the second magnetic field azimuth signal, so that magnetic field angle information is generated based on the magnetic field detection angle, the purpose of expanding the detection range of the rotation angle of the external magnetic field is achieved, and the problem that the current AMR sensor can only measure the rotation angle of the magnetic field of 180 degrees is solved.

Drawings

FIG. 1 is a schematic diagram of the modular connection of a magnetic encoder according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a magnetic encoder according to an embodiment of the present application;

FIG. 3 is a schematic diagram of the module connection of a magnetic encoder according to an embodiment of the present application;

FIG. 4 is a schematic circuit diagram of a magnetic field angle sensing module according to an embodiment of the present application;

FIG. 5 is a schematic waveform diagram of a magnetic field angle detection assembly and a magnetic field orientation sensing module according to one embodiment of the present application;

FIG. 6 is a schematic circuit diagram of a magnetic encoder according to an embodiment of the present application;

FIGS. 7 and 8 are schematic diagrams of the ABZ signal output by a magnetic encoder provided by one embodiment of the present application;

FIG. 9 is a schematic diagram of the UVW signal output by a magnetic encoder according to one embodiment of the present application;

fig. 10 is a flowchart illustrating an operation method of a magnetic encoder according to an embodiment of the present application.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

Position sensors are typically used to detect the position of an electric machine, in particular the position of the rotor of the electric machine. In the case of a linear motor, the position sensor detects a linear position, and in the case of a rotary motor, the position sensor detects an angular position. The angular position must be determined to control an electrically commutated motor, abbreviated as EC motor, such as a brushless dc motor, abbreviated as BLDC motor, or a permanent magnet synchronous motor, abbreviated as PMSM. The EC motor is basically an absolute system within one rotor pole pair, the position sensor also providing an absolute angular output of the mechanical position relative to the motor shaft. Since the position sensor is used as a feedback sensor for the motor shaft position, alignment of the angular domain is required, however, the current position sensor is generally detected by an AMR sensor, which has a problem in that only a 180 ° rotation angle can be detected.

Example 1

Referring to fig. 1, a magnetic encoder according to an embodiment of the present application includes: the magnetic field angle detection assembly 10, the first magnetic field orientation sensing module 21, the second magnetic field orientation sensing module 22, and the data fusion module 32.

Specifically, the magnetic field angle detection assembly 10 is configured to generate a magnetic field detection angle that cyclically changes with 180 ° as a period according to a magnetic field angle change of an external magnetic field, the magnetic field angle detection assembly 10 has a first vector direction and a second vector direction, the first vector direction is perpendicular to the second vector direction, and when the magnetic field direction of the external magnetic field is parallel to the first vector direction, the magnetic field detection angle is 0 ° or 180 °.

Specifically, the magnetic field angle detection assembly 10 is configured to be sensitive to a magnetic field angle, and is configured to accurately detect a magnetic field angle within a certain range, for example, the magnetic field angle detection assembly 10 accurately detects a magnetic field angle between 0 ° and 180 ° with a period of 180 ° as a period, and generates two pairs of differential voltage signals corresponding to a magnetic field rotation angle according to a magnetic field intensity change generated when an external magnetic field rotates, where the two pairs of differential voltage signals may be a first differential signal and a second differential signal, respectively, and the first differential signal and the second differential signal are proportional to sin2A and cos2A of the magnetic field detection angle a, and at this time, the arctangent processing module 12 may calculate the magnetic field detection angle a based on sin2A, cos a and a preset arctangent function.

Specifically, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are configured to detect an orientation of a magnetic field rotation, where the first magnetic field orientation sensing module 21 generates a first magnetic field orientation signal based on a rotation angle of an external magnetic field, and the second magnetic field orientation sensing module 22 generates a second magnetic field orientation signal based on the rotation angle of the external magnetic field.

Referring to fig. 2, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 may be respectively provided in a first vector direction (see Y in fig. 2) and a second vector direction (see X in fig. 2) of the magnetic field angle detection assembly 10, and the first magnetic field orientation signal may be in a first level state when the magnetic field direction of the external magnetic field coincides with the first vector direction, and in a second level state when the magnetic field direction of the external magnetic field is opposite to the first vector direction, wherein the first level state may be in a high level state and the second level state may be in a low level state.

Since the first vector direction is perpendicular to the second vector direction, the positions of the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are also perpendicular to the position of the magnetic field angle detection assembly 10, when the magnetic field direction of the external magnetic field is consistent with the second vector direction, the second magnetic field orientation signal assumes a first level state, and when the magnetic field direction of the external magnetic field is opposite to the second vector direction, the second magnetic field orientation signal assumes a second level state.

In one specific application embodiment, the first vector direction may be the Y-axis direction of the magnetic field angle detection assembly 10, and the second vector direction may be the X-axis direction of the magnetic field angle detection assembly 10.

The data fusion module 32 is connected to the magnetic field angle detection assembly 10, the first magnetic field direction sensing module 21 and the second magnetic field direction sensing module 22, and the data fusion module 32 can perform fusion calculation according to the first magnetic field azimuth signal, the second magnetic field azimuth signal and the magnetic field detection angle, so as to generate magnetic field angle information.

For example, in one particular application embodiment, the magnetic field angle information includes a rotation angle of the external magnetic field, and the data fusion module 32 may determine a corresponding rotation angle range for determining the external magnetic field from the first magnetic field orientation signal and the second magnetic field orientation signal, and then determine the rotation angle of the external magnetic field based on the rotation angle range.

The data fusion module 32 may further determine a corresponding rotation angle calculation formula for determining the rotation angle of the external magnetic field according to the first magnetic field azimuth signal and the second magnetic field azimuth signal, and calculate according to the rotation angle calculation formula of the magnetic field detection angle, so as to obtain the rotation angle of the external magnetic field.

Since the magnetic field angle detection assembly 10 generates a magnetic field detection angle cyclically changing with 180 ° according to a magnetic field angle change of an external magnetic field, for example, when the magnetic field angle detection assembly 10 is an AMR sensor, it obtains 2A to be 90 ° and 450 ° through an arctangent function calculation under the condition of outputting the same set of differential signals (a first differential signal and a second differential signal), and at this time, the magnetic field rotation angle a can be 45 ° and 225 ° which are both in a range of 360 ° and are 180 ° different, and therefore, an angle range or a rotation angle calculation formula of the external magnetic field can be determined through the first magnetic field azimuth signal and the second magnetic field azimuth signal, so as to obtain an accuracy value of an angle represented by an output signal of the magnetic field angle detection assembly 10 based on the angle range or the rotation angle calculation formula.

In one embodiment, referring to FIG. 3, the magnetic field angle detection assembly 10 includes a magnetic field angle sensing module 11 and an arctangent processing module 12.

The magnetic field angle sensing module 11 is configured to generate a first differential signal and a second differential signal according to a magnetic field angle change of an external magnetic field.

The arctangent processing module 12 is connected with the magnetic field angle sensing module 11 and the data fusion module 32, and the arctangent processing module 12 is used for determining the magnetic field detection angle according to the first differential signal, the second differential signal and a preset arctangent function.

The magnetic field angle sensing module 11 is configured to accurately detect a magnetic field angle between 0 and 180 °, generate two pairs of differential voltage signals corresponding to the magnetic field rotation angle according to a magnetic field intensity change generated when the external magnetic field rotates, that is, a first differential signal and a second differential signal, where the first differential signal and the second differential signal are respectively proportional to sin2A and cos2A of the magnetic field detection angle a, and at this time, the arctangent processing module 12 may calculate the magnetic field detection angle a based on sin2A, cos a and a preset arctangent function.

In one embodiment, the magnetic encoder further comprises a substrate, and in particular, the magnetic field angle detection assembly 10, the first magnetic field orientation sensing module 21, and the second magnetic field orientation sensing module 22 are disposed on the same side of the substrate.

Specifically, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are disposed on the same plane with the magnetic field angle detection assembly 10, and the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are respectively disposed in the first vector direction and the second vector direction of the magnetic field angle detection assembly 10, so that the same horizontal plane is used as a reference monitoring position to detect the rotation of the magnetic field, and the error of magnetic field detection is avoided.

In one embodiment, the distance between the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 and the magnetic field angle detection assembly 10 is the same.

Specifically, the first magnetic field orientation sensing module 21 is located in a first vector direction of the magnetic field angle detection assembly 10, a distance between the first magnetic field orientation sensing module 21 and the magnetic field angle detection assembly 10 is a first distance, the second magnetic field orientation sensing module 22 is located in a second vector direction of the magnetic field angle detection assembly 10, and a distance between the second magnetic field orientation sensing module 22 and the magnetic field angle detection assembly 10 is a second distance.

In one embodiment, the angle between the first vector direction of the magnetic field angle detection assembly 10 and the second vector direction is 90 °, for example, with the magnetic field angle detection assembly 10 as the origin of coordinates, the first vector direction may be the Y-axis direction, and the second vector direction may be the X-axis direction.

In one embodiment, the distance between the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 and the magnetic field angle detection assembly 10 is less than 3cm.

In one embodiment, miniaturization of the magnetic encoder can be achieved by setting the lengths of the first distance and the second distance to be less than 3cm, and detection errors caused by an excessively large volume of the magnetic encoder are avoided.

In one embodiment, the magnetic field angle sensing module 11 may be an AMR sensor.

Specifically, the AMR sensor may also be called an anisotropic magnetoresistive sensor, in which when the external magnetic field and the direction of the built-in magnetic field of the magnet form zero degrees, the resistance does not change with the change of the external magnetic field, and when a certain angle exists between the external magnetic field and the built-in magnetic field of the magnet, the magnetization vector inside the magnet shifts, and the sheet resistance decreases.

In one embodiment, the magnetic field angle sensitive module 11 comprises a plurality of anisotropic magneto resistances.

The anisotropic magneto resistors respectively form a first Wheatstone bridge and a second Wheatstone bridge, the first Wheatstone bridge is used for outputting a first differential signal according to the angle change of an external magnetic field, the second Wheatstone bridge is used for outputting a second differential signal according to the angle change of the external magnetic field, and an included angle between the second Wheatstone bridge and the first Wheatstone bridge is 45 degrees.

Specifically, referring to fig. 4, the first wheatstone bridge may be composed of a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4, and the second wheatstone bridge may be composed of a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8.

The first Wheatstone bridge is used for outputting a first differential signal according to the magnetic field angle change of the external magnetic field; the second wheatstone bridge is configured to output a second differential signal according to a magnetic field angle change of an external magnetic field, where the first differential signal and the second differential signal are both differential signal pairs, and an included angle between the second wheatstone bridge and the first wheatstone bridge is 45 °, for example, an included angle between the fifth resistor R5 and the first resistor R1 is 45 °, an included angle between the sixth resistor R6 and the second resistor R2 is 45 °, an included angle between the seventh resistor R7 and the third resistor R3 is 45 °, and an included angle between the eighth resistor R8 and the fourth resistor R4 is 45 °.

The AMR sensor outputs two pairs of differential voltages based on the detected magnetic field rotation angle, vx+ and Vx-are respectively the first line voltage and the second line voltage of the first differential signal, specifically, the common node of the fifth resistor R5 and the seventh resistor R7 outputs the first line voltage Vx+ of the first differential signal, the common node of the sixth resistor R6 and the eighth resistor R8 outputs the second line voltage Vx-, vy+ and Vy-of the first differential signal, respectively, the common node of the first resistor R1 and the third resistor R3 outputs the first line voltage vy+ of the second differential signal, the common node of the second resistor R2 and the fourth resistor R4 outputs the second line voltage Vy-, of the second differential signal, and Vx and Vy are respectively proportional to sin2A and cos2A of the magnetic field angle A, and the first Wheatstone bridge and the second Wheatstone bridge respectively output sine signals and cosine signals.

In one embodiment, the arctangent processing module 12 is specifically configured to determine the magnetic field detection angle according to the following arctangent function:

A＝(1/2)*arctan(Vx/Vy)； (1)

wherein a is a magnetic field detection angle, vx= (vx+) - (Vx-), vy= (vy+) - (Vy-), vx+, vx-are the first line voltage and the second line voltage of the first differential signal, respectively, and vy+, vy-are the first line voltage and the second line voltage of the second differential signal, respectively.

Specifically, the output range of the magnetic field angle sensing module 11 is 180 degrees, the output signal of the magnetic field angle sensing module 11 is two pairs of differential voltages, vx=sin2a, vy=cos 2a, and Vx/vy=tan 2A can be obtained; at this time, the arctangent function determines a magnetic field detection angle a= (1/2) arctan (Vx/Vy).

In one embodiment, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 each include a tunnel magnetoresistance, the magnetization direction of the fixed layer of the tunnel magnetoresistance of the first magnetic field orientation sensing module 21 coincides with the first vector direction, and the magnetization direction of the fixed layer of the tunnel magnetoresistance of the second magnetic field orientation sensing module 22 coincides with the second vector direction.

The magnetization direction of the fixed layer of the tunnel magnetoresistance is unchanged, the magnetization direction of the free layer is changed under the action of an external field, and at the moment, the magnetization intensities of the two magnetic layers are changed relative to each other, so that large resistance change can be observed on a magnetic tunnel junction crossing the insulating layer, thereby utilizing the angle change of a magnetic field to cause the magnetoresistance change, when the magnetization directions of the free layer and the fixed layer are parallel, the resistance becomes smaller, the current flowing at the moment becomes larger, and when the magnetization directions of the free layer and the fixed layer are antiparallel, the resistance changes, and the current flowing at the moment becomes smaller.

In one embodiment, the first magnetic field orientation sensing module 21 may be a TMR sensor.

In one embodiment, the second magnetic field orientation sensing module 22 may be a TMR sensor.

The TMR sensor comprises a free layer and a fixed layer, mainly based on TMR effect, for detecting the rotation angle of a magnetic field, wherein an insulator or a semiconductor is arranged between the magnetic fixed layer and the magnetic free layer at intervals, when the magnetization direction of the magnetic free layer is changed under the action of an external field, and the magnetization direction of the fixed layer is unchanged, at the moment, the relative orientation of the magnetization intensities of the two magnetic layers is changed, then a large resistance change can be observed on a magnetic tunnel junction crossing the insulating layer, therefore, the TMR sensor utilizes the angle change of the magnetic field to cause magneto-resistance change, when the magnetization directions of the free layer and the fixed layer are parallel, the resistance is reduced, the current flowing at the moment is increased, and when the magnetization directions of the free layer and the fixed layer are antiparallel, the resistance is changed, and the current flowing at the moment is reduced.

In one embodiment, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are each TMR sensors, and the magnetic field angle sensing module 11 comprises an anisotropic magnetoresistance. The magnetization direction of the fixed layer of the tunnel magnetoresistance of the first magnetic field orientation sensing module 21 coincides with the first vector direction, the magnetization direction of the fixed layer of the tunnel magnetoresistance of the second magnetic field orientation sensing module 22 coincides with the second vector direction, and the magnet built-in magnetic field direction of the anisotropic magnetoresistance coincides with the first vector direction. According to the anisotropic magnetoresistance effect of permalloy, the resistance value of the anisotropic magnetoresistance is cyclically changed by two cycles during 360 ° rotation of the external magnetic field relative to the anisotropic magnetoresistance.

In another embodiment, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are TMR sensors, and the magnetic field angle sensing module 11 includes a first wheatstone bridge and a second wheatstone bridge, which are respectively composed of four anisotropic magneto-resistors (as shown in fig. 4). The magnetization direction of the fixed layer of the tunnel magnetoresistance of the first magnetic field orientation sensing module 21 coincides with the first vector direction, and the magnetization direction of the fixed layer of the tunnel magnetoresistance of the second magnetic field orientation sensing module 22 coincides with the second vector direction. In this case, the first vector direction is settable by software for the magnetic field angle-sensitive module 11.

Specifically, the angle detection range of the AMR sensor is 0-180 degrees, the angle detection range of the TMR sensor is 0-360 degrees, and the 360-degree angle detection with higher precision can be completed through the mutual matching of one AMR and two TMRs.

Table 1:

table 1 is a table of output changes of the first magnetic field orientation sensing module 21 (TMR 1) and the second magnetic field orientation sensing module 22 (TMR 2).

Referring to fig. 5 and table 1, in some cases, for example, because of being affected by a process error or a temperature drift, the output level states of the first magnetic field orientation sensing module 21 (TMR 1) and the second magnetic field orientation sensing module 22 (TMR 2) are not stable at their level switching points.

The level switching point of the first magnetic field orientation sensing module 21 (TMR 1) includes θ=0°, 180 °, and the level switching point of the second magnetic field orientation sensing module 22 (TMR 2) includes θ=90°, 270 °.

In some examples, the output of TMR1 is not stable when θ is located in an interval of (-45 °,45 °) or (135 °,225 °); when θ is located in an interval of (45 °,135 °) or (225 °,315 °), the output of TMR2 is not stable. If the magnetic encoder has only one of TMR1 and TMR2, the calculation result of the rotation angle θ of the external magnetic field may be affected by a process error or a temperature drift, which may be erroneous.

The magnetic encoder provided by the application is provided with TMR1 and TMR2, and the data fusion module 32 reads the output of the TMR1 or TMR2 according to the situation, so that the problem of influence of process errors or temperature drift on detection accuracy can be solved.

In one embodiment, the magnetic field angle information may include a rotation direction, a rotation angle, and a rotation period.

In one embodiment, the data fusion module 32 determines rotation angle information of the external magnetic field based on the first magnetic field orientation signal, the second magnetic field orientation signal, and the magnetic field detection angle.

Table 2:

table 2 is a table showing the relationship among the magnetic field detection angle a, the first magnetic field azimuth signal, the second magnetic field azimuth signal, and the rotation angle θ of the external magnetic field.

Referring to Table 2, when A <45 DEG is not less than 0 DEG, if the second magnetic field azimuth signal is in the first level state (i.e. high level, stable is 1), determining θ=A; if the second magnetic field azimuth signal is in the second level state (i.e., is low level and stable to 0), θ=a+180° is determined.

When a is less than or equal to 0 degrees and less than or equal to 45 degrees, a calculation formula of the rotation angle theta of the external magnetic field can be judged only according to the second magnetic field azimuth signal output by the second magnetic field azimuth sensitive module 22, at the moment, if the second magnetic field azimuth signal is in a first level state, theta=a is determined to be between 0 and 180 degrees, namely theta=a+180 degrees is determined to be between 180 degrees and 360 degrees, and if the second magnetic field azimuth signal is in a second level state, the first magnetic field azimuth signal output by the first magnetic field azimuth sensitive module 21 can be in a first level state or in a second level state.

When the angle A is less than or equal to 45 degrees and less than 135 degrees, determining theta=A if the first magnetic field azimuth signal is in the first level state; if the first magnetic field orientation signal is in the second level state, θ=a+180° is determined.

When the angle a is less than or equal to 45 degrees and less than 135 degrees, the calculation formula of the rotation angle θ of the external magnetic field can be judged only according to the first magnetic field azimuth signal output by the first magnetic field azimuth sensitive module 21, at this time, if the first magnetic field azimuth signal is in a first level state, θ=a, that is, θ is between 0 and 180 degrees, and if the first magnetic field azimuth signal is in a second level state, θ=a+180 degrees, that is, θ is between 180 degrees and 360 degrees, and the first magnetic field azimuth signal output by the second magnetic field azimuth sensitive module 22 can be in the first level state or the second level state.

When the angle A is more than or equal to 135 degrees and less than 180 degrees, determining theta=A if the second magnetic field azimuth signal is in the second level state; if the second magnetic field azimuth signal is in the first level state, determining θ=a+180°; wherein A represents the magnetic field detection angle, and θ represents the rotation angle of the external magnetic field.

When the angle a is less than or equal to 135 degrees and less than 180 degrees, the calculation formula of the rotation angle θ of the external magnetic field can be judged only according to the second magnetic field azimuth signal output by the second magnetic field azimuth sensitive module 22, at this time, if the second magnetic field azimuth signal is in the second level state, θ=a, that is, θ is between 0 and 180 degrees, and if the second magnetic field azimuth signal is in the first level state, θ=a+180 degrees, that is, θ is between 180 degrees and 360 degrees, and the first magnetic field azimuth signal output by the first magnetic field azimuth sensitive module 21 can be in the first level state or in the second level state.

Specifically, a rotation angle calculation formula of the external magnetic field can be determined according to the first magnetic field orientation signal and the second magnetic field orientation signal generated by the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22, and the rotation angle θ of the external magnetic field is calculated based on the rotation angle calculation formula and the magnetic field detection angle a outputted by the magnetic field angle detection assembly 10.

In one embodiment, the magnetic field angle information may also include a rotation angle range, a rotation period, a rotation direction, etc. of the external magnetic field.

For example, the received rotation angle signal is encoded to characterize the rotation angle of the magnetic field, and after each 360 rotation of the magnetic field, the output is increased by one rotation period,

in one embodiment, the magnetic field detection angle of the external magnetic field is described with reference to the output signals of the TMR sensor and the AMR sensor in fig. 5, wherein TMR1 represents the signal waveform of the first magnetic field orientation signal output by the first magnetic field orientation sensing module 21, TMR2 represents the signal waveform of the second magnetic field orientation signal output by the second magnetic field orientation sensing module 22, the AMR Y axis represents the waveform of the first differential signal, the AMR X axis represents the waveform of the second differential signal, θ represents the actual rotation angle of the external magnetic field, and a represents the magnetic field detection angle output by the AMR sensor.

Specifically, the first magnetic field orientation sensing module 21 is configured to monitor the embodiment of the magnetic field direction change on the Y axis, generate a first magnetic field orientation signal, and the second magnetic field orientation sensing module 22 is configured to monitor the embodiment of the magnetic field direction change on the X axis, generate a second magnetic field orientation signal, where "0" in the output signals of the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 indicates a low level, and "1" indicates a high level.

In one embodiment, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are TMR sensors, the magnetic field angle detection assembly 10 is an AMR sensor, and the phase difference between the first magnetic field orientation signal and the second magnetic field orientation signal is 90 ° because the magnetization directions of the fixed layers in the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are perpendicular as shown in table 2.

The magnetic field orientation sensing module may be used to detect the rotation angle range of the external magnetic field, for example, when the rotation angle of the external magnetic field is 80 °, the output of the magnetic field orientation sensing module may be high due to the process error or the temperature drift, and the level drift, and the second magnetic field orientation signal output by the second magnetic field orientation sensing module 22 may be influenced by the process error or the temperature drift, and the second magnetic field orientation signal may be low due to the fact that the angle a obtained by performing arctangent calculation on the differential signal output by the magnetic field angle detection assembly 10 may be 80 ° (see the point A1 in fig. 5) or 260 ° (see the point A2 in fig. 5), and the output result may be 80 ° or 260 ° due to the probability that the level of the output of the second magnetic field orientation sensing module 22 alone is hopped.

By adding the first magnetic field azimuth sensitive module 21, if the first magnetic field azimuth signal output by the first magnetic field azimuth sensitive module 21 is at a high level at this time, the rotation angle of the external magnetic field can be determined to be 80 °, if the first magnetic field azimuth signal output by the first magnetic field azimuth sensitive module 21 is at a low level, the rotation angle of the external magnetic field can be determined to be 260 °, and since the 80 ° distance from the level jump angle of the first magnetic field azimuth sensitive module 21 is larger than the angle difference between 0 ° and 180 °, the possibility of level jump does not exist, the level stability of the first magnetic field azimuth signal output by the first magnetic field azimuth sensitive module 21 is higher, thereby increasing the reliability of the detection result.

Further, if the rotation angle of the external magnetic field is 181 °, if only the first magnetic field orientation sensing module 21 detects the orientation of the rotation angle of the external magnetic field, the output of the first magnetic field orientation sensing module 21 may be at a high level or may be at a low level because 181 ° is close to 180 °, and at this time, the angle a obtained by performing arctangent calculation on the differential signal output by the magnetic field angle detection assembly 10 may be 181 ° or 1 °, and the output result may be 181 ° or 1 ° because of the probability of jump in the output level of the single first magnetic field orientation sensing module 21, so the reliability of the detection result is low.

By adding the second magnetic field azimuth sensitive module 22, if the second magnetic field azimuth signal output by the second magnetic field azimuth sensitive module 22 is at a high level at this time, the rotation angle of the external magnetic field can be determined to be 1 °, if the second magnetic field azimuth signal output by the second magnetic field azimuth sensitive module 22 is at a low level, the rotation angle of the external magnetic field can be determined to be 181 °, and since the angle difference between the level jump angle of 1 ° and the level jump angle of the first magnetic field azimuth sensitive module 21 is larger, the possibility of level jump does not exist, and the level stability of the first magnetic field azimuth signal output by the second magnetic field azimuth sensitive module 22 is higher, thereby increasing the reliability of the detection result.

In one embodiment, when 0 DEG.ltoreq.A <45 DEG, if the second magnetic field azimuth signal is in the first level state, determining that the rotation angle of the external magnetic field is in the range of 0 DEG to 45 DEG; if the second magnetic field azimuth signal is in the second level state, the rotation angle range of the external magnetic field is determined to be 180-225 degrees.

Specifically, as shown in the waveform diagram of fig. 5, if a is less than or equal to 0 ° and less than or equal to 45 °, since a is close to 0 °, the first magnetic field azimuth signal may be unstable in level due to a process error or a temperature drift of the magnetic field azimuth sensitive module, for example, may be in a first level state or may be in a second level state, and the level of the second magnetic field azimuth signal is stably output in the first level state or the second level state, so that the rotation angle range of the external magnetic field can be determined according to the level state of the second magnetic field azimuth signal, and further the rotation angle θ of the external magnetic field can be determined, for example, the first level state is high level, the second level state is low level, if the second magnetic field azimuth signal is low level, the rotation angle range of the external magnetic field is determined to be 180 ° to 225 °, and the rotation angle θ of the external magnetic field can be determined based on the rotation angle range and the magnetic field detection angle a, and the difference between θ and a is 180 °.

When the angle A is less than or equal to 45 degrees and less than 135 degrees, if the first magnetic field azimuth signal is in a first level state, determining that the rotation angle range of the external magnetic field is 45 degrees to 135 degrees; if the first magnetic field azimuth signal is in the second level state, the rotation angle range of the external magnetic field is determined to be 225-315 degrees.

Specifically, if a is 45 ° or less and less than 135 °, because a is close to 90 °, the second magnetic field azimuth signal may be unstable in level due to a process error or a temperature drift of the magnetic field azimuth sensitive module, for example, may be in a first level state or may be in a second level state, and the level of the first magnetic field azimuth signal is stably output in the first level state or the second level state, so that the rotation angle range of the external magnetic field can be determined according to the level state of the first magnetic field azimuth signal, and further the rotation angle θ of the external magnetic field can be confirmed.

For example, if the first magnetic field azimuth signal is at a high level, it is determined that the rotation angle range of the external magnetic field is 45 ° to 135 °, the rotation angle θ of the external magnetic field can be confirmed based on the rotation angle range and the magnetic field detection angle a, and when θ coincides with a, and if the first magnetic field azimuth signal is at a low level, it is determined that the rotation angle range of the external magnetic field is 225 ° to 315 °, the rotation angle θ of the external magnetic field can be confirmed based on the rotation angle range and the magnetic field detection angle a, and when θ differs from a by 180 °.

When the angle A is more than or equal to 135 degrees and less than 180 degrees, if the second magnetic field azimuth signal is in the second level state, determining that the rotation angle range of the external magnetic field is 135 degrees to 180 degrees; and if the second magnetic field azimuth signal is in the first level state, determining that the rotation angle range of the external magnetic field is 315-360 degrees.

Specifically, if a is less than or equal to 135 ° and less than 180 °, because a is close to 180 °, at this time, the first magnetic field azimuth signal may jump due to a process error or a temperature drift of the magnetic field azimuth sensitive module, and may be in a first level state or a second level state, and the level of the second magnetic field azimuth signal is stably output in the first level state or the second level state, so that the rotation angle range of the external magnetic field can be determined according to the level state of the second magnetic field azimuth signal, and the rotation angle θ of the external magnetic field can be further confirmed.

For example, if the second magnetic field azimuth signal is at a low level, it is determined that the rotation angle range of the external magnetic field is 135 ° +.a <180 °, the rotation angle θ of the external magnetic field can be confirmed based on the rotation angle range and the magnetic field detection angle a, and when θ coincides with a, and if the second magnetic field azimuth signal is at a high level, it is determined that the rotation angle range of the external magnetic field is 315 ° to 360 °, the rotation angle θ of the external magnetic field can be confirmed based on the rotation angle range and the magnetic field detection angle a, and when θ differs from a by 180 °.

In one embodiment, the output range of the magnetic field angle detection assembly 10 is 180 degrees, the output signals thereof are two pairs of differential voltages, vx=sin2a, vy=cos 2a, thereby obtaining Vx/vy=tan 2A, and since the period of the tangent function is 180 degrees, the magnetic field detection angle a= (1/2) arctan (Vx/Vy) is determined based on the arctangent function, the resulting rotation angle has two different values within 360 °, and the two different values differ by 180 °.

Specifically, since the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 have already determined the rotation angle range of the external magnetic field, the calculation unit selects the corresponding rotation angle calculation formula based on the rotation angle range, and calculates the rotation angle of the external magnetic field.

For example, when the rotation angle range is 0 ° to 45 °, the rotation angle of the calculated magnetic field is θ=a, when the rotation angle range is 45 ° to 135 °, the rotation angle of the calculated magnetic field is θ=a, when the rotation angle range is 180 ° to 225 °, the rotation angle of the calculated magnetic field is θ=a+180°, and when the rotation angle range is 225 ° to 315 ° and 315 ° to 360 °, the rotation angle of the calculated magnetic field is θ=a+180°.

In one embodiment, fig. 6 is a schematic structural diagram of a magnetic encoder, and referring to fig. 6, the data fusion module 32 may be integrated in the magnetic encoder chip 41, and the data reading module 42 may be an MCU or other data reading chip for reading data from the magnetic encoder chip 41.

Specifically, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 are respectively connected to a pin TMRX and a pin TMRY of the magnetic encoder chip 41, and are used for sending a first magnetic field orientation signal and a second magnetic field orientation signal to the magnetic encoder chip 41, and differential signal output pins of the magnetic field angle detection assembly 10 are respectively connected to differential signal input pins (pins SINP, SINN, COSP, COSN) of the magnetic encoder chip 41 in a one-to-one correspondence manner, and are used for sending a first differential signal and a second differential signal to the magnetic encoder chip 41, and SCLK pin, CSEL pin, MOSI pin and MISO pin of the magnetic encoder chip 41 are respectively connected to SCLK pin, CSEL pin, MOSI pin and MISO pin of the data reading module 42 in a one-to-one correspondence manner.

The plurality of data pins (pin P0, pin P1, pin P2, pin P3, pin P4, pin P5) of the magnetic encoder chip 41 are used to transmit rotation angle data, which may include at least one of a digital signal in ABZ form, a digital signal in UVW form, and a digital signal in PWM form, to the data reading module 42.

For example, fig. 7 is a schematic diagram of a rotation direction of the angle encoding unit according to the rotation angle signal, and as described below with reference to fig. 7, ABZ may be used to characterize the rotation direction of the magnetic field, where the B output signal leads the a signal by one quarter period when the magnetic field rotates in the forward direction, and conversely, where the a output signal leads the B signal by one quarter period when the magnetic field rotates in the reverse direction, and the Z signal indicates that the current position is 0.

Specifically, the Z signal may be used to indicate that the current angle is 0, and its width may be adjusted by the 6-bit OTP parameter ABZIND, and the specific parameter corresponds to the pattern shown in fig. 8.

Further, the resolution of ABZ can be adjusted by the OTP12 bit parameter AZBPPT, which can range from 4PPR to 16384PP.

Further, in order to control the over 0 point stability of the ABZ signal, a certain hysteresis may be inserted into the ABZ output, and the inserted hysteresis range may be directly input with the corresponding hysteresis angle value by the 16-bit MTP parameter ABZHYS.

In one specific application embodiment, the ABZ signal may be normally output 16ms after the magnetic encoder chip 41 is powered up.

In one embodiment, fig. 9 is a schematic diagram of a rotation period of the angle encoding unit performing encoding processing according to a rotation angle signal, a digital signal in a UVW form may be used to represent the number of rotation periods of a magnetic field, and after the magnetic field rotates 360 degrees, the angle encoding unit outputs 1 period (antipole number) respectively, and fig. 9 is a schematic diagram of signals with an antipole number of 1 and a duty ratio of 1:1, where UVW signals have a delay of one third period between each other, and the number of UVW antipole can be changed to 256 by adjusting an 8-bit parameter UVWPOLS of the OTP.

Example 2

The embodiment of the application also provides a working method of the magnetic encoder, and the working method in the embodiment can be applied to the magnetic encoder in any one of the embodiments.

Referring to fig. 10, the working method includes steps S10, S20, and S30.

In step S10, a magnetic field detection angle cyclically varying by 180 ° is generated from a magnetic field angle variation of the external magnetic field.

In step S20, a first magnetic field orientation signal and a second magnetic field orientation signal are generated.

In step S30, magnetic field angle information is generated from the first magnetic field azimuth signal, the second magnetic field azimuth signal, and the magnetic field detection angle.

Specifically, as shown in fig. 1, in step S10, the magnetic field angle detection assembly 10 may be configured to generate a magnetic field detection angle that cyclically changes by 180 ° according to a magnetic field angle change of an external magnetic field, where the first vector direction and the second vector direction of the magnetic field angle detection assembly 10 are set to be perpendicular, and when the magnetic field direction of the external magnetic field is parallel to the first vector direction, the magnetic field detection angle output by the magnetic field angle detection assembly 10 is 0 ° or 180 °.

In step S20, the azimuth signals of the external magnetic field may be detected by the two magnetic field azimuth sensitive modules, and the first magnetic field azimuth signal and the second magnetic field azimuth signal are generated according to the change of the external magnetic field, and when the magnetic field direction of the external magnetic field is consistent with the first vector direction, the first magnetic field azimuth signal is in the first level state; when the magnetic field direction of the external magnetic field is opposite to the first vector direction, the first magnetic field azimuth signal is in a second level state; when the magnetic field direction of the external magnetic field is consistent with the second vector direction, the second magnetic field azimuth signal is in the first level state; the second magnetic field orientation signal assumes the second level state when a magnetic field direction of the external magnetic field is opposite to the second vector direction.

Specifically, as shown in fig. 1, the direction of the magnetic field rotation can be detected by the first magnetic field direction sensing module 21 and the second magnetic field direction sensing module 22, wherein the first magnetic field direction sensing module 21 generates a first magnetic field direction signal based on the rotation angle of the external magnetic field, and the second magnetic field direction sensing module 22 generates a second magnetic field direction signal based on the rotation angle of the external magnetic field.

As shown in fig. 2, the first magnetic field orientation sensing module 21 and the second magnetic field orientation sensing module 22 may be respectively disposed in a first vector direction (see Y in fig. 2) and a second vector direction (see X in fig. 2) of the magnetic field angle detection assembly 10, and the first magnetic field orientation signal may be in a first level state when the magnetic field direction of the external magnetic field coincides with the first vector direction, and may be in a second level state when the magnetic field direction of the external magnetic field is opposite to the first vector direction, wherein the first level state may be in a high level state and the second level state may be in a low level state.

In a specific application embodiment, the magnetization direction of the fixed layer of the first magnetic field orientation sensing module 21 is parallel to the first vector direction of the magnetic field angle detection assembly 10, and the magnetization direction of the fixed layer of the second magnetic field orientation sensing module 22 is parallel to the second vector direction of the magnetic field angle sensing module, and since the first vector direction is perpendicular to the second vector direction, the first vector direction may be the Y-axis direction and the second vector direction may be the X-axis direction, so that the angular range of the magnetic field rotation and the number of rotations of the external magnetic field may be determined based on the first magnetic field orientation signal and the second magnetic field orientation signal.

In one embodiment, in step S30, when 0 is less than or equal to A <45, if the second magnetic field orientation signal is in the first level state (i.e., high level, stable 1), then θ=A; if the second magnetic field azimuth signal is in a second level state (i.e., is in a low level and is stable to be 0), determining θ=a+180°; wherein A represents the magnetic field detection angle, and θ represents the rotation angle of the external magnetic field.

When the angle A is more than or equal to 135 degrees and less than 180 degrees, determining theta=A if the second magnetic field azimuth signal is in the second level state; if the second magnetic field orientation signal is in the first level state, θ=a+180° is determined.

The magnetic field orientation sensing module may be used to detect the rotation angle range of the external magnetic field, for example, when the rotation angle of the external magnetic field is 80 °, the output of the magnetic field orientation sensing module may be high due to the process error or the temperature drift, and the level drift, and the second magnetic field orientation signal output by the second magnetic field orientation sensing module 22 may be influenced by the process error or the temperature drift, and the second magnetic field orientation signal may be low due to the fact that the angle a obtained by performing arctangent calculation on the differential signal output by the magnetic field angle detection assembly 10 may be 80 ° (see the point A1 in fig. 6) or 260 ° (see the point A2 in fig. 6), and the output result may be 80 ° or 260 ° due to the probability that the level of the output of the second magnetic field orientation sensing module 22 alone is hopped.

Further, if the rotation angle of the external magnetic field is 181 °, if only the first magnetic field orientation sensing module 21 detects the orientation of the rotation angle of the external magnetic field, since 181 ° is close to 180 °, the output of the first magnetic field orientation sensing module 21 may be at a high level or at a low level, and at this time, the angle a obtained by performing arctangent calculation on the differential signal output by the magnetic field angle detecting module 10 may be 180 ° or 1 °, and since there is a possibility of jump in the output level of the single first magnetic field orientation sensing module 21, the output result may be displayed as 180 ° or 1 °, and thus the reliability of the detection result is low.

In one embodiment, in step S30, when 0 DEG.ltoreq.A <45 DEG, if the second magnetic field azimuth signal is in the first level state, determining that the rotation angle of the external magnetic field is in the range of 0 DEG to 45 DEG; if the second magnetic field azimuth signal is in the second level state, the rotation angle range of the external magnetic field is determined to be 180-225 degrees.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.

The functional units in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated modules/units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present application may implement all or part of the flow in the above embodiments, or may be implemented by a computer program instructing related hardware, and the computer program may be stored in a computer readable storage medium, which when executed by a processor, may implement the steps of the respective method embodiments described above. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, executable files or in some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. A magnetic encoder, the magnetic encoder comprising:

the first magnetic field direction sensing module is used for generating a first magnetic field azimuth signal, the first magnetic field azimuth signal is in a first level state when the magnetic field direction of the external magnetic field is consistent with the first vector direction, and the first magnetic field azimuth signal is in a second level state when the magnetic field direction of the external magnetic field is opposite to the first vector direction;

The second magnetic field direction sensing module is used for generating a second magnetic field azimuth signal, the second magnetic field azimuth signal is in the first level state when the magnetic field direction of the external magnetic field is consistent with the second vector direction, and the second magnetic field azimuth signal is in the second level state when the magnetic field direction of the external magnetic field is opposite to the second vector direction;

2. The magnetic encoder of claim 1, wherein the magnetic field angle detection assembly comprises a magnetic field angle sensing module and an arctangent processing module;

3. The magnetic encoder of claim 2, wherein the magnetic field angle sensitive module comprises a plurality of anisotropic magnetoresistors;

4. The magnetic encoder of claim 3, wherein the arctangent processing module is specifically configured to determine the magnetic field detection angle according to the following arctangent function:

A＝(1/2)*arctan(Vx/Vy)；

5. The magnetic encoder of claim 1, wherein the first magnetic field direction sensing module and the second magnetic field direction sensing module each comprise a tunneling magnetoresistance, a magnetization direction of a fixed layer of the tunneling magnetoresistance of the first magnetic field direction sensing module is coincident with the first vector direction, and a magnetization direction of a fixed layer of the tunneling magnetoresistance of the second magnetic field direction sensing module is coincident with the second vector direction.

6. The magnetic encoder of any of claims 1 to 5, wherein the data fusion module is specifically configured to:

7. The magnetic encoder of any of claims 1 to 5, wherein the data fusion module is specifically configured to:

wherein a represents the magnetic field detection angle.

8. A method of operating a magnetic encoder, the method comprising:

9. The method of operation of claim 8, wherein said generating magnetic field angle information from said first magnetic field orientation signal, said second magnetic field orientation signal, and said magnetic field detection angle comprises:

10. The method of operation of claim 8, wherein said generating magnetic field angle information from said first magnetic field orientation signal, said second magnetic field orientation signal, and said magnetic field detection angle comprises:

wherein a represents the magnetic field detection angle.