Motor angle detection device based on Hall sensor

Abstract

The utility model discloses a motor angle detection device based on a Hall sensor, which is arranged on a motor, the motor comprises a motor main body (1) with a stator and a rotor, one end of the motor main body (1) is provided with a main shaft (2) connected with the rotor, and the motor angle detection device comprises a slave shaft (3) connected with the rotor. The slave shaft (3) is provided with a radially magnetized annular permanent magnet (4); a circuit board (5) is arranged at the end part of the motor main body (1); a magnetic field detection and conversion circuit (6) and a voltage operation circuit (7) are arranged on the circuit board (5); according to the utility model, the slave shaft connected with the rotor is arranged, and the annular permanent magnet is arranged on the slave shaft, so that the rotation state of the rotor can be obtained by cooperating with the magnetic field detection conversion circuit and the voltage operation circuit at one side, thereby realizing motor angle detection. The transmission and installation space of the main shaft is not occupied, the practicability is good, and meanwhile the device has the advantage of being low in component cost.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a motor angle detection device based on a Hall sensor. Background Technology

[0002] Servo and stepper motors play a vital role in modern industrial control systems, widely used in precision positioning, speed control, and automated production lines. To ensure accurate position control and stable operation, they must be combined with encoders. Encoders include photoelectric encoders and magnetic encoders. Magnetic encoders, in particular, have strong anti-interference capabilities, are suitable for harsh environments such as oil and dust, and have a long service life.

[0003] Currently, magnetic encoders on the market are mainly of two types: coaxial and off-axis. Coaxial encoders require the magnetic sensor to be directly installed at the end of the shaft, which limits the installation space of the shaft and is also affected by the vibration caused by the rotation of the shaft, resulting in poor operational reliability. Off-axis magnetic encoders, as shown in Chinese invention patent publication number CN107565762A, include components such as a ring magnet and an encoder board. They detect rotation by the change in magnetic field generated during the rotation of the ring magnet causing different voltages to be generated by the Hall elements on the encoder board. However, the encoder board needs to be set on the tail end of the motor shaft, which still occupies the transmission and installation space of the motor shaft, resulting in poor practicality. In addition, this invention uses four evenly distributed ring Hall elements for detection, and the encoder board used for electrical connection also needs to have a large area, resulting in high component costs. Utility Model Content

[0004] The purpose of this invention is to provide a motor angle detection device based on a Hall sensor. This invention includes a slave shaft connected to the rotor, and a ring-shaped permanent magnet is mounted on the slave shaft. Combined with a magnetic field detection conversion circuit and a voltage calculation circuit on one side, the rotational state of the rotor can be obtained, thereby realizing motor angle detection. This invention does not occupy the transmission and installation space of the main shaft, has excellent practicality, and also features low component cost.

[0005] The technical solution of this utility model is as follows: A motor angle detection device based on a Hall sensor is installed on a motor. The motor includes a motor body with a stator and a rotor. One end of the motor body is provided with a main shaft connected to the rotor. The motor angle detection device includes a slave shaft connected to the rotor, and a radially magnetized annular permanent magnet is provided on the slave shaft. A circuit board is provided at the end of the motor body. The circuit board is provided with a magnetic field detection and conversion circuit and a voltage calculation circuit. The detection surface of the magnetic field detection and conversion circuit is parallel to the rotation surface of the annular permanent magnet. The magnetic field detection and conversion circuit includes a first Hall sensor and a second Hall sensor installed on the circuit board and connected to the voltage calculation circuit. The detection direction of the first Hall sensor is perpendicular to the detection direction of the second Hall sensor.

[0006] In the aforementioned motor angle detection device based on a Hall sensor, the voltage calculation circuit includes a signal conditioning circuit connected to a magnetic field detection and conversion circuit. The output terminal of the signal conditioning circuit is connected to a control chip, and the output terminal of the control chip is connected to a communication circuit.

[0007] In the aforementioned motor angle detection device based on a Hall sensor, the main shaft and the driven shaft are solid shafts.

[0008] In the aforementioned motor angle detection device based on a Hall sensor, the circuit board is fan-shaped, with a gap between its inner edge and the annular permanent magnet.

[0009] In the aforementioned motor angle detection device based on a Hall sensor, the detection direction extension line of the first Hall sensor passes through the center of the annular permanent magnet.

[0010] In the aforementioned motor angle detection device based on a Hall sensor, the motor body is provided with a protective cover covering the circuit board, and the center of the protective cover has an opening adapted to the driven shaft.

[0011] In the aforementioned motor angle detection device based on a Hall sensor, a calibration module is electrically connected to the signal output terminal of the voltage calculation circuit.

[0012] Compared to existing technologies, this invention allows the rotor of the motor body to rotate simultaneously, driving the driven shaft to rotate as well. The annular permanent magnet on the driven shaft rotates accordingly. Because the annular permanent magnet is radially magnetized, the magnetic field on the side where the circuit board is located continuously changes. The magnetic field detection and conversion circuit receives these changes and outputs the resulting voltage to the voltage calculation circuit. The voltage calculation circuit then uses the voltage value to determine the rotor's rotation state, thereby enabling motor angle detection. Therefore, this invention performs detection from the driven shaft side, without occupying space on the main shaft side. Simultaneously, the magnetic field detection and conversion circuit detects magnetic field changes from one side, simplifying the circuit board area and reducing the number of components, thus lowering manufacturing costs. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model;

[0014] Figure 2 This is a schematic diagram of the installation of the circuit board and the driven shaft of this utility model;

[0015] Figure 3 This is a connection diagram of the calibration module of this utility model;

[0016] Figure 4 This is a schematic diagram of the working process of this utility model;

[0017] Figure 5 This is a schematic diagram of the circuit structure of the first Hall sensor of this utility model;

[0018] Figure 6 This is a schematic diagram of the circuit structure of the signal conditioning circuit of this utility model;

[0019] Figure 7 This is a schematic diagram of the circuit structure of the control chip of this utility model;

[0020] Figure 8 This is a schematic diagram of the circuit structure of the communication circuit of this utility model.

[0021] The labels in the attached diagram are as follows: 1. Motor body; 2. Main shaft; 3. Slave shaft; 4. Ring permanent magnet; 5. Circuit board; 6. Magnetic field detection and conversion circuit; 7. Voltage calculation circuit; 8. Signal conditioning circuit; 9. Control chip; 10. Communication circuit; 11. First Hall sensor; 12. Second Hall sensor; 13. Protective cover; 14. Opening; 15. Calibration module; 16. Digital signal circuit. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0023] Example: A motor angle detection device based on a Hall sensor, as shown in the attached figure. Figure 1 As shown, the device is mounted on a motor, which includes a motor body 1 with a stator and a rotor. Torque is generated through the interaction of magnetic fields, causing the rotor to rotate. This is a technique well-known and mastered by those skilled in the art. One end of the motor body 1 is provided with a main shaft 2 connected to the rotor. The motor angle detection device includes a driven shaft 3 connected to the rotor. The main shaft and the driven shaft are rotatably connected to the end of the motor body via bearings, and the inner end transmits motion to the rotor through a keyway. (See attached diagram.) Figure 2As shown, a radially magnetized annular permanent magnet 4 is fixed on shaft 3, meaning the magnetic poles of the annular permanent magnet change from N pole to S pole radially. A circuit board 5 located on one side of shaft 3 is mounted at the end of the motor body 1. A magnetic field detection and conversion circuit 6 and a voltage calculation circuit 7 are mounted on the circuit board 5. The detection surface of the magnetic field detection and conversion circuit 6 is parallel to the rotation surface of the annular permanent magnet 4, ensuring that changes in the magnetic field during rotation can be captured. The magnetic field detection and conversion circuit 6 includes a first Hall sensor 11 and a second Hall sensor 12 mounted on the circuit board 5 and connected to the voltage calculation circuit 7. The detection direction of the first Hall sensor 11 is perpendicular to the detection direction of the second Hall sensor 12. The circuits of the first Hall sensor and the second Hall sensor are identical, and the circuit structure is shown in the attached figure. Figure 5 The techniques shown are well-known and mastered by those skilled in the art, and will not be described in detail here; the voltage calculation circuit 7 includes a signal conditioning circuit 8 connected to the magnetic field detection and conversion circuit 6, as shown in the attached figure. Figure 6 As shown, the signal conditioning circuit 8 is used to filter the output signal of the magnetic field detection and conversion circuit. The output terminal of the signal conditioning circuit 8 is connected to the control chip 9 (CPU), as shown in the attached diagram. Figure 7 As shown, after acquiring the signal, the magnetic field strength, position, and direction are determined by judging its magnitude. Then, a pulse signal containing the rotational position, speed, and direction of the shaft is output. The output terminal of the control chip 9 is connected to a communication circuit 10 and a digital signal circuit 16. The communication circuit is shown in the attached diagram. Figure 8As shown, signal output is achieved through a communication circuit. The magnetic field detection and conversion circuit 6 and voltage calculation circuit 7 in this embodiment are common processing circuits in the art, belonging to techniques well-known and mastered by those skilled in the art; therefore, this utility model will not elaborate further. The main shaft 2 and the driven shaft 3 are solid shafts, and the circuit board and related circuits are located on the side of the rotating component, freeing up space on the driven shaft and the main shaft. The circuit board 5 is fan-shaped, with a gap between its inner edge and the annular permanent magnet 4, simplifying the circuit board area and reducing space occupation. The magnetic field detection and conversion circuit 6 includes a first Hall sensor 11 and a second Hall sensor 12 mounted at the same position on the circuit board 5. The detection direction of the first Hall sensor 11 is perpendicular to the detection direction of the second Hall sensor 12. Both sensor 11 and the second Hall sensor 12 are connected to the voltage calculation circuit 7. They detect magnetic field strength in different directions and generate sine and cosine signals at 90° intervals. Since the first and second Hall sensors have different values ​​at different angles of the annular permanent magnet, an algorithm can be used to convert the values ​​to angles from 0 to 360°. The detection direction extension line of the first Hall sensor 11 passes through the center of the annular permanent magnet 4, making it more sensitive to changes in the magnetic field. The motor body 1 is equipped with a protective cover 13 covering the circuit board 5. The protective cover 13 has an opening 14 in the middle that matches the shaft 3. The protective cover is a magnetic shield to shield external magnetic fields, improving detection accuracy and preventing external dust and foreign objects from damaging the circuit board 5. (See attached...) Figure 3 As shown, the signal output terminal of the voltage calculation circuit 7 is electrically connected to a calibration module 15. The calibration module is a register, a high-speed storage unit for the control chip to temporarily store instructions, data, and addresses. The calibration module is used to store the compensation data calculated by the control chip. It calibrates the voltage calculation circuit through error calculation and interpolation calculation to compensate for deviations such as mechanical installation and Hall sensitivity. Since there are certain deviations in mechanical installation, Hall sensitivity, and magnetic ring magnetization, the voltage calculation circuit needs to be calibrated to improve accuracy. The rotor moves at a constant speed through an external control signal. The voltage calculation circuit continuously reads the angle signal value through the magnetic field detection conversion circuit. After the acquisition is completed, error calculation and interpolation calculation are performed, and the compensation data is updated in the voltage calculation circuit.

[0024] Working principle: Initialization phase: as shown in the appendix Figure 4 As shown, the control chip 9 and the calibration module 15 are initialized. After the calibration module 15 is initialized, the external control signal sends a signal to the drive circuit of the motor body 1, causing the rotor to start rotating at a constant speed.

[0025] Calibration data acquisition and processing stage: During the uniform rotation of the rotor, the driven shaft 3 rotates synchronously, and the annular permanent magnet 4 on the driven shaft 3 also rotates together. Since the annular permanent magnet 4 is radially magnetized, its rotation causes the magnetic field on the side where the circuit board 5 is located to change continuously. The first Hall sensor 11 and the second Hall sensor 12 in the magnetic field detection and conversion circuit 6, because their detection directions are perpendicular to each other, can detect changes in magnetic field strength in different directions and convert the magnetic field changes into changing voltage signals, which are output to the voltage calculation circuit 7. The signal conditioning circuit 8 in the voltage calculation circuit 7 first filters these voltage signals to remove noise interference and make the signals more stable and accurate. The filtered signals are input to the control chip 9. The control chip 9 calculates the driven shaft angle value under the corresponding magnetic field line based on these signals and outputs the angle value and the corresponding data of the magnetic field line to the calibration module 15. After collecting the data, the calibration module 15 performs error calculation and interpolation calculation to obtain compensation data and updates the compensation data in the voltage calculation circuit 7, completing the calibration of the voltage calculation circuit 7 and improving the accuracy of subsequent angle detection.

[0026] Normal operating phase: After calibration, the motor enters normal operating mode. When the rotor rotates, it simultaneously drives the main shaft 2 and the driven shaft 3 to rotate. The ring-shaped permanent magnet 4 on the driven shaft 3 rotates continuously, causing the magnetic field on the side where the circuit board 5 is located to change continuously. The magnetic field detection and conversion circuit 6 continuously receives the changes in the magnetic field and outputs the changing voltage to the voltage calculation circuit 7. The voltage calculation circuit 7 analyzes and calculates the input voltage signal based on the angle value and magnetic field line data obtained from the previous calibration, thereby achieving accurate detection of the rotor's rotation state, including information such as rotation position, speed, and direction. The calculated rotation state information is processed by the control chip 9 and output through the communication circuit 10 and the digital signal circuit for use by external devices to achieve precise control of the motor. The two different output methods better meet different application needs.

[0027] The above embodiments merely illustrate the implementation of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. Furthermore, in these embodiments, "up," "down," "left," "right," "front," and "back" represent relative positions only, not absolute positions. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A motor angle detection device based on a Hall sensor, mounted on a motor, the motor comprising a motor body (1) having a stator and a rotor, wherein one end of the motor body (1) is provided with a main shaft (2) connected to the rotor, characterized in that: The motor angle detection device includes a slave shaft (3) connected to the rotor, and a radially magnetized annular permanent magnet (4) is provided on the slave shaft (3); a circuit board (5) is provided at the end of the motor body (1), and a magnetic field detection conversion circuit (6) and a voltage calculation circuit (7) are provided on the circuit board (5). The detection surface of the magnetic field detection conversion circuit (6) is parallel to the rotation surface of the annular permanent magnet (4); the magnetic field detection conversion circuit (6) includes a first Hall sensor (11) and a second Hall sensor (12) disposed on the circuit board (5) and connected to the voltage calculation circuit (7). The detection direction of the first Hall sensor (11) is perpendicular to the detection direction of the second Hall sensor (12).

2. The motor angle detection device based on a Hall sensor according to claim 1, characterized in that: The voltage calculation circuit (7) includes a signal conditioning circuit (8) connected to the magnetic field detection and conversion circuit (6). The output terminal of the signal conditioning circuit (8) is connected to a control chip (9), and the output terminal of the control chip (9) is connected to a communication circuit (10).

3. The motor angle detection device based on a Hall sensor according to claim 1, characterized in that: The main shaft (2) and the slave shaft (3) are solid shafts.

4. The motor angle detection device based on a Hall sensor according to claim 1, characterized in that: The circuit board (5) is fan-shaped, and there is a gap between its inner edge and the annular permanent magnet (4).

5. The motor angle detection device based on a Hall sensor according to claim 1, characterized in that: The detection direction extension line of the first Hall sensor (11) passes through the center of the annular permanent magnet (4).

6. The motor angle detection device based on a Hall sensor according to claim 1, characterized in that: The motor body (1) is provided with a protective cover (13) covering the circuit board (5), and the center of the protective cover (13) has an opening (14) adapted to the driven shaft (3).

7. The motor angle detection device based on a Hall sensor according to claim 1, characterized in that: The voltage calculation circuit (7) is electrically connected to a calibration module (15) at its signal output terminal.

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