Magnetic Field Direction Detection Method and System

Abstract

The present invention discloses a magnetic field direction detection method and system. The method includes: generating a magnetic field with two poles on the surface of a permanent magnet facing the sensor; arranging a plurality of Hall elements, and each Hall element detecting the change signal of the magnetic field component in a set direction; obtaining different signals according to the induction signals of different Hall elements, and calculating the magnetic field direction of the permanent magnet by analyzing each signal. The magnetic field direction detection method and system proposed by the present invention can improve the accuracy of permanent magnet angle detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic field detection, and relates to a magnetic field detection system, and particularly to a method and system for detecting the direction of a magnetic field. Background Art

[0002] An existing method for detecting the direction of a magnetic field is as follows. Refer to Figure 1 、 Figure 2 . A pair of pole-magnetized (N-S) permanent magnets are used, and four Hall elements 10, 20, 30, and 40 are arranged uniformly at 90° below the permanent magnets. By using the Hall effect, when the permanent magnet rotates around the central axis, the four Hall elements receive the change signal of the magnetic field component in the Z direction and output Hall voltages. By analyzing the Hall voltages, the rotation angle of the permanent magnet can be determined.

[0003] In some usage environments with relatively high safety requirements, such as in the automotive electronics field, the sensor needs to be made into two channels to prevent safety accidents caused by one channel not working. The existing solutions can only be arranged in the following ways: stacked or placed side by side. As shown in Figure 3-1 、 Figure 3-2 、 Figure 4-1 、 Figure 4-2 . For the stacked placement as shown in Figure 3-1 、 Figure 3-2 , the distances between the two groups of Hall elements and the permanent magnet are different, so the magnitudes and directions of the magnetic field components in the Z direction sensed by them will be different. For another example, as shown in Figure 4-1 Figure 4-1 、 Figure 4-2 for side-by-side placement, there is an offset distance between the centers of each of the two groups of Hall elements and the center of the permanent magnet. Although the signals obtained by the two groups of Hall elements are the same in this way, there is an influence of axis offset on the signal itself, and both groups of signals are not accurate enough. It can be seen that no matter which method is adopted, signals without differences or offsets cannot be obtained, and errors in measuring the magnetic field direction will be caused.

[0004] In view of this, there is an urgent need to design a new method for detecting the direction of a magnetic field to overcome at least some of the above-mentioned defects existing in the existing methods for detecting the direction of a magnetic field. Summary of the Invention

[0005] The present invention provides a method and system for detecting the direction of a magnetic field, which can improve the accuracy of detecting the angle of a permanent magnet.

[0006] To solve the above technical problems, according to one aspect of the present invention, the following technical solution is adopted:

[0007] A method for detecting the direction of a magnetic field, the method comprising:

[0008] Setting a plurality of Hall elements, and each Hall element detects a change signal of a magnetic field component in a set direction;

[0009] Obtain different signals according to the induction signals of different Hall elements, and calculate the magnetic field direction by analyzing each signal.

[0010] As an embodiment of the present invention, the method further includes: generating a magnetic field with two poles on the surface of the permanent magnet facing the sensor by the permanent magnet.

[0011] As an embodiment of the present invention, a magnetic sensor is provided, and 4 Hall elements are arranged inside the magnetic sensor. The 4 Hall elements are evenly and dispersedly arranged, and the included angle between the center connection line of adjacent Hall elements and the center of the magnetic field is 45°.

[0012] As an embodiment of the present invention, two magnetic sensors are provided. 4 Hall elements are arranged inside each magnetic sensor. The 4 Hall elements in one magnetic sensor are evenly and dispersedly arranged, and the included angle between the center connection line of adjacent Hall elements and the center of the magnetic field is 45°;

[0013] The two magnetic sensors are arranged side by side and can rotate around the rotation axis of the permanent magnet; the distances between the two magnetic sensors and the permanent magnet are the same, and there is no offset relative to the rotation axis of the permanent magnet.

[0014] As an embodiment of the present invention, when the permanent magnet rotates one week, the 4 Hall elements will sense the change of the Z-direction magnetic field component; sense two pairs of opposite sine and cosine signals, and the sensed signals are two cycles; the 4 Hall elements are the first Hall element, the second Hall element, the third Hall element and the fourth Hall element in sequence;

[0015] By subtracting the first Hall element from the third Hall element and subtracting the second Hall element from the fourth Hall element; obtaining the amplified first signal and second signal, and calculating the magnetic field direction of the permanent magnet by analyzing the first signal and the second signal.

[0016] According to another aspect of the present invention, the following technical solution is adopted: a magnetic field direction detection system, the magnetic field direction detection system includes:

[0017] A plurality of Hall elements, each Hall element is used to detect the change signal of the magnetic field component in the set direction;

[0018] A magnetic field direction analysis module, which is used to obtain different signals according to the induction signals of different Hall elements, and calculate the magnetic field direction by analyzing each signal.

[0019] As an embodiment of the present invention, the magnetic field direction detection system further includes a permanent magnet, and a magnetic field with two poles is generated on the surface of the permanent magnet facing the sensor by the permanent magnet.

[0020] As an embodiment of the present invention, the magnetic field direction detection system includes a magnetic sensor, and 4 Hall elements are arranged inside the magnetic sensor. The 4 Hall elements are evenly and dispersedly arranged, and the included angle between the connection line of the centers of adjacent Hall elements and the center of the magnetic field is 45°.

[0021] As an embodiment of the present invention, the magnetic field direction detection system includes two magnetic sensors. 4 Hall elements are arranged inside each magnetic sensor. The 4 Hall elements in one magnetic sensor are evenly and dispersedly arranged, and the included angle between the connection line of the centers of adjacent Hall elements and the center of the magnetic field is 45°;

[0022] The two magnetic sensors are arranged side by side and can rotate around the rotation axis of the permanent magnet; the distances of the two magnetic sensors from the permanent magnet are the same, and there is no offset relative to the rotation axis of the permanent magnet.

[0023] As an embodiment of the present invention, the 4 Hall elements included in each magnetic sensor are successively the first Hall element, the second Hall element, the third Hall element, and the fourth Hall element;

[0024] The magnetic field direction analysis module subtracts the first Hall element from the third Hall element and subtracts the second Hall element from the fourth Hall element; to obtain the amplified first signal and second signal, and calculates the magnetic field direction of the permanent magnet by analyzing the first signal and the second signal.

[0025] The beneficial effect of the present invention is that the magnetic field direction detection method and system proposed by the present invention can improve the accuracy of permanent magnet angle detection.

[0026] In a usage scenario of the present invention, by changing the magnetization method of the permanent magnet, a 2-pole magnetic field (N-S-N-S) is presented on the sensor detection surface. One path of Hall elements in the sensor can be configured within the range of N-S, and the other path of Hall elements can be configured within the magnetic field range of the other half, so that after the permanent magnet rotates one week, the Z-direction magnetic field components detected by the two paths of Hall elements are completely the same, and there is no influence of offset relative to the rotation axis; making the detection of the angle of the permanent magnet more accurate. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the existing method for detecting the magnetic field direction.

[0028] Figure 2 It is another schematic diagram of the existing method for detecting the magnetic field direction.

[0029] Figure 3-1 It is a schematic diagram (front view) of two groups of Hall elements placed in a stacked manner to sense the Z-direction magnetic field.

[0030] Figure 3-2 It is a schematic diagram (top view) of two groups of Hall elements placed in a stacked manner to sense the Z-direction magnetic field.

[0031] Figure 4-1 Schematic diagram (front view) of sensing the magnetic field in the Z direction by placing two sets of Hall elements side by side.

[0032] Figure 4-2 Schematic diagram (top view) of sensing the magnetic field in the Z direction by placing two sets of Hall elements side by side.

[0033] Figure 5 Schematic diagram of magnetizing a permanent magnet in an embodiment of the present invention.

[0034] Figure 6 Schematic diagram of magnetizing a permanent magnet in an embodiment of the present invention.

[0035] Figure 7 Schematic diagram of magnetizing a permanent magnet in an embodiment of the present invention.

[0036] Figure 8 Schematic diagram of the layout of Hall elements in an embodiment of the present invention.

[0037] Figure 9 Schematic diagram of the layout of Hall elements in an embodiment of the present invention.

[0038] Figure 10 Graph showing the relationship between the rotation of the permanent magnet and the change in the Z - direction magnetic field component sensed by the Hall elements in the present invention. Detailed implementation manners

[0039] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] To further understand the present invention, the preferred implementation schemes of the present invention will be described below with reference to embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0041] The description of this part only focuses on several typical embodiments, and the present invention is not limited to the scope described in the embodiments. The mutual replacement of some technical features of the same or similar prior art means and the embodiments is also within the scope of the description and protection of the present invention.

[0042] The expression of the steps in each embodiment in the specification is only for convenience of description, and the implementation manner of the present application is not limited by the order of step implementation. The "connection" in the specification includes both direct connection and indirect connection.

[0043] The present invention discloses a method for detecting the magnetic field direction, and the method includes:

[0044] Setting a plurality of Hall elements, and each Hall element detects the change signal of the magnetic field component in a set direction;

[0045] Obtain different signals according to the induction signals of different Hall elements, and calculate the magnetic field direction by analyzing each signal.

[0046] In an embodiment of the present invention, the method further includes: generating a magnetic field with two poles on the surface of the permanent magnet facing the sensor direction by the permanent magnet. Figures 5 to 7 This is a magnetization schematic diagram of the permanent magnet in an embodiment of the present invention; there are many methods to generate a magnetic field with two poles, and two generation methods are listed here Figures 5 to 7 .

[0047] Figure 8 This is a layout schematic diagram of the Hall element in an embodiment of the present invention; please refer to Figure 8 , in an embodiment of the present invention, a magnetic sensor is provided, and 4 Hall elements are arranged inside the magnetic sensor, and the 4 Hall elements are arranged at 45°; the magnetic sensor is arranged within half of the corresponding magnetic field range. In one embodiment, the above-mentioned 45° arrangement means that the 4 Hall elements are evenly and dispersedly arranged, and the included angle between the center line of adjacent Hall elements and the center of the magnetic field (such as the center of the permanent magnet) is 45°. In another embodiment, the 45° arrangement means that the 4 Hall elements are distributed around a center point, and the central angle of any radius R distribution (such as the included angle between the center line of adjacent Hall elements and the magnetic field center)

[0048] Figure 9 This is a layout schematic diagram of the Hall element in an embodiment of the present invention; please refer to Figure 9 , in another embodiment of the present invention, two magnetic sensors are provided, and 4 Hall elements are arranged inside each sensor, and the two magnetic sensors are arranged side by side; 8 Hall elements are evenly distributed around the rotation axis of the permanent magnet. The distances of the two magnetic sensors from the permanent magnet are the same, and there is no offset relative to the rotation axis of the permanent magnet; the magnetic field directions detected by the two magnetic sensors are the same and accurate.

[0049] When the permanent magnet rotates one week, the 4 Hall elements will sense the change of the Z-direction magnetic field component; the positive and cosine signals that are opposite to each other in pairs and are two cycles; the 4 Hall elements are the first Hall element 1, the second Hall element 2, the third Hall element 3, and the fourth Hall element 4 in sequence. By subtracting the first Hall element 1 from the third Hall element 3, and subtracting the second Hall element 2 from the fourth Hall element 4; the amplified first signal and second signal are obtained, and the magnetic field direction of the permanent magnet is calculated by analyzing the first signal and the second signal (the signal diagram can be referred to Figure 10)。In one embodiment, the angle of 90° between the first Hall element 1 and the third Hall element 3 is twice the angle of 45° of a single polarity of the permanent magnet; therefore, the magnitudes of the magnetic fields detected by the first Hall element 1 and the third Hall element 3 are the same, but the magnetic poles are opposite; by subtraction, a signal amplified by a factor of 2 can be obtained. Similarly, subtracting the second Hall element 2 and the fourth Hall element 4 gives a signal amplified by a factor of 2.

[0050] The present invention also discloses a magnetic field direction detection system, which includes: a plurality of Hall elements and a magnetic field direction analysis module. Each Hall element is used to detect the change signal of the magnetic field component in a set direction; the magnetic field direction analysis module is used to obtain different signals according to the induction signals of different Hall elements, and calculate the magnetic field direction by analyzing each signal.

[0051] In one embodiment of the present invention, the magnetic field direction detection system further includes a permanent magnet, which generates a magnetic field with two poles on the surface of the permanent magnet facing the sensor.

[0052] Please refer to Figure 8 , in one embodiment of the present invention, the magnetic field direction detection system includes a magnetic sensor, and 4 Hall elements are arranged inside the magnetic sensor in a 45° layout; the magnetic sensor occupies half of the magnetic field range. The above 45° layout means that the 4 Hall elements are evenly and dispersedly arranged, and the included angle between the center line connecting the centers of adjacent Hall elements and the center of the magnetic field is 45°.

[0053] Please refer to Figure 9 , in another embodiment of the present invention, the magnetic field direction detection system includes two magnetic sensors, and 4 Hall elements are arranged inside each magnetic sensor. The two magnetic sensors are arranged side by side; around the rotation axis of the permanent magnet, 8 Hall elements are evenly distributed; the distances between the two magnetic sensors and the permanent magnet are the same, and there is no offset relative to the rotation axis of the permanent magnet; the magnetic field directions detected by the two magnetic sensors are the same and accurate.

[0054] In one embodiment, the 4 Hall elements in each magnetic sensor are successively the first Hall element, the second Hall element, the third Hall element, and the fourth Hall element. The magnetic field direction analysis module subtracts the first Hall element and the third Hall element, and subtracts the second Hall element and the fourth Hall element; to obtain the amplified first signal and second signal, and calculates the magnetic field direction of the permanent magnet by analyzing the first signal and the second signal.

[0055] In summary, the magnetic field direction detection method and system proposed by the present invention can improve the accuracy of permanent magnet angle detection.

[0056] In a usage scenario of the present invention, by changing the magnetization method of the permanent magnet, a two-pole magnetic field (N-S-N-S) is presented on the detection surface of the sensor. One path of Hall elements in the sensor can be configured within the range of N-S, and the other path of Hall elements can be configured within the magnetic field range of the other half. After the permanent magnet rotates one week, the Z-direction magnetic field components detected by the two paths of Hall elements are exactly the same, and there is no influence of offset relative to the rotation axis, making the detection of the angle of the permanent magnet more accurate.

[0057] It should be noted that the present application can be implemented in software and / or a combination of software and hardware. For example, it can be implemented using an application-specific integrated circuit (ASIC), a general-purpose computer, or any other similar hardware device. In some embodiments, the software program of the present application can be executed by a processor to implement the above steps or functions. Similarly, the software program of the present application (including related data structures) can be stored in a computer-readable recording medium, such as a RAM memory, a magnetic or optical drive, or a floppy disk and similar devices. Additionally, some steps or functions of the present application can be implemented using hardware, such as a circuit that cooperates with the processor to execute each step or function.

[0058] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as these combinations of technical features do not conflict, they should be considered as falling within the scope described in this specification.

[0059] The description and application of the present invention here are illustrative and do not intend to limit the scope of the present invention to the above embodiments. The effects or advantages involved in the embodiments may not be reflected in the embodiments due to various factors. The description of the effects or advantages is not used to limit the embodiments. The deformations and changes of the embodiments disclosed here are possible, and the substitutions and equivalent components of the embodiments are well-known to those of ordinary skill in the art. Those skilled in the art should clearly understand that the present invention can be implemented in other forms, structures, arrangements, proportions, and using other components, materials, and parts without departing from the spirit or essential characteristics of the present invention. Other deformations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A method for detecting the magnetic field direction, characterized in that, The method includes: Generating a magnetic field with two pairs of poles on the surface of the permanent magnet facing the sensor by the permanent magnet; Setting a plurality of Hall elements, and each Hall element detects the change signal of the magnetic field component in the set direction; Obtaining different signals according to the induction signals of different Hall elements, and calculating the magnetic field direction by analyzing each signal; Setting two magnetic sensors, with 4 Hall elements arranged inside each magnetic sensor. The 4 Hall elements in one magnetic sensor are evenly and dispersedly arranged, and the included angle between the center connection line of adjacent Hall elements and the center of the magnetic field is 45°; The two magnetic sensors are arranged side by side and can rotate around the rotation axis of the permanent magnet; the two magnetic sensors are at the same distance from the permanent magnet and do not deviate from the rotation axis of the permanent magnet; A magnetic field of two pairs of poles N-S-N-S is presented on the sensor detection surface. One path of Hall elements in the sensor is arranged within the range of N-S, and the other path of Hall elements is arranged within the other half of the magnetic field range, so that after the permanent magnet rotates one week, the Z-direction magnetic field components detected by the two paths of Hall elements are exactly the same, and there is no influence of deviation relative to the rotation axis.

2. The method for detecting the magnetic field direction according to claim 1, characterized in that: When the permanent magnet rotates one week, the 4 Hall elements will sense the change of the Z-direction magnetic field component; sense two pairs of opposite sine and cosine signals, and the sensed signals are two cycles; the 4 Hall elements are successively the first Hall element, the second Hall element, the third Hall element and the fourth Hall element; By subtracting the first Hall element from the third Hall element, and subtracting the second Hall element from the fourth Hall element; Obtaining the amplified first signal and second signal, and calculating the magnetic field direction of the permanent magnet by analyzing the first signal and the second signal.

3. A magnetic field direction detection system, characterized in that, The magnetic field direction detection system includes: A plurality of Hall elements, and each Hall element is used to detect the change signal of the magnetic field component in the set direction; A magnetic field direction analysis module, which is used to obtain different signals according to the induction signals of different Hall elements, and calculate the magnetic field direction by analyzing each signal; A permanent magnet, which generates a magnetic field with two pairs of poles on the surface of the permanent magnet facing the sensor; The magnetic field direction detection system includes two magnetic sensors, with 4 Hall elements arranged inside each magnetic sensor. The 4 Hall elements in one magnetic sensor are evenly and dispersedly arranged, and the included angle between the center connection line of adjacent Hall elements and the center of the magnetic field is 45°; The two magnetic sensors are arranged side by side and can rotate around the rotation axis of the permanent magnet; the two magnetic sensors are at the same distance from the permanent magnet and do not deviate from the rotation axis of the permanent magnet; A magnetic field of two pairs of poles N-S-N-S is presented on the sensor detection surface. One path of Hall elements in the sensor is arranged within the range of N-S, and the other path of Hall elements is arranged within the other half of the magnetic field range, so that after the permanent magnet rotates one week, the Z-direction magnetic field components detected by the two paths of Hall elements are exactly the same, and there is no influence of deviation relative to the rotation axis.

4. The magnetic field direction detection system according to claim 3, characterized in that: The 4 Hall elements included in each magnetic sensor are successively the first Hall element, the second Hall element, the third Hall element and the fourth Hall element; The magnetic field direction analysis module subtracts the first Hall element from the third Hall element, and subtracts the second Hall element from the fourth Hall element; Obtain the amplified first signal and second signal, and calculate the magnetic field direction of the permanent magnet by analyzing the first signal and the second signal.

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