Brushless motor encoder based on Wiegand sensor

Abstract

The utility model relates to a brushless motor encoder based on Wiegand sensors, and belongs to the technical field of encoders, the brushless motor encoder comprises a turntable and a plurality of Wiegand sensors, a plurality of magnets are arranged on the turntable at equal intervals along the circumferential direction of the turntable, the connecting line of the N-pole end and the S-pole end of each magnet is parallel to the central axis of the turntable, and the polarities of the magnetic poles of two adjacent magnets are opposite. The plurality of Wiegand sensors are arranged around the rotating disc and are arranged at equal intervals in the circumferential direction of the rotating disc, and the central axis of sensitive wires of the Wiegand sensors is parallel to the central axis of the rotating disc. The encoder with the Wiegand sensor has the effects of improving the precision of the pulse signal output by the encoder applying the Wiegand sensor and adapting to a high-speed rotation application scene.

Description

Technical Field

[0001] The present application relates to the technical field of encoders, and in particular to a brushless motor encoder based on a Wiegand sensor. Background Art

[0002] In brushless motors, encoders play a crucial feedback role, primarily used to accurately detect the angle, position, and speed of the motor's rotor. Traditional Hall sensors are widely used in brushless motor encoders, but they suffer from low resolution, limited sensitivity, and susceptibility to environmental interference. With the increasing demand for high-performance motor drive systems, Wiegand sensors, which require no power supply, offer high temperature stability, and provide stable signal output, are gaining industry attention for their application in encoders. The advantages of Wiegand sensors make them a worthy option, particularly in applications requiring high precision, high speed, and high dynamic response.

[0003] For example, Chinese invention patent publication number CN107655510A discloses a multi-turn absolute value encoder and position detection method. The method utilizes the cooperation of a Wiegand sensor and a permanent magnet to enable the Wiegand sensor to output an electrical signal pulse. The electrical signal pulse divides the circumference of the permanent magnet into multiple angle intervals, allowing the microcontroller circuit to determine the multi-turn absolute angle value of the object to be measured based on the single-turn absolute angle value and the electrical signal pulse.

[0004] However, due to the characteristics of the Wiegand sensor, only when a certain polarity magnetic field parallel to the sensitive wire of the Wiegand sensor reaches the triggering magnetic induction intensity will the magnetic domains in the sensitive wire be stimulated to move, the magnetization direction instantly turning to the same direction, and the magnetic field in the space around the sensitive wire also changing instantaneously, so that the Wiegand sensor can induce an electrical pulse. In the magnetic ring structure adopted by the above-mentioned patent, most of the magnetic field lines are arranged along the radial direction of the sensitive wire, and the magnetic field lines cannot form a closed loop on the sensitive wire. Even if this design has some magnetic induction lines arranged along the circumference of the sensitive wire, the magnetic field strength is weak, so there is a situation where the Wiegand effect cannot be effectively triggered, and a usable electrical signal pulse cannot be accurately output. At the same time, under high-speed rotation, there may still be sinusoidal signals generated by the inductance and unusable pulse signals. Utility Model Content

[0005] In order to improve the accuracy of the pulse signal output by an encoder using a Wiegand sensor and adapt to high-speed rotation application scenarios, the present application provides a brushless motor encoder based on a Wiegand sensor.

[0006] The present application provides a brushless motor encoder based on a Wiegand sensor, which adopts the following technical solutions:

[0007] A brushless motor encoder based on a Wiegand sensor includes a turntable and several Wiegand sensors. The turntable is provided with several magnets arranged equidistantly along its circumference. The line connecting the N-terminal end and the S-terminal end of each magnet is parallel to the central axis of the turntable. The magnetic poles of two adjacent magnets have opposite polarities. The several Wiegand sensors are arranged around the turntable and equidistantly along the circumference of the turntable. The central axes of the sensitive wires of the Wiegand sensors are parallel to the central axis of the turntable. The number of magnets is an even number and is not an integer multiple of the number of Wiegand sensors.

[0008] By adopting the above technical solution, in such a magnet distribution, most of the magnetic field lines can form a closed loop along the sensitive wire of the Wiegand sensor, ensuring that the Wiegand effect can be accurately triggered;

[0009] And because the N and S poles of the magnet are arranged alternately, and every time the turntable rotates, the sensor can generate a clear pulse signal every time it detects a change in the magnetic poles, thereby providing clearer pulse edges and improving signal accuracy and resolution;

[0010] The number of magnets cannot be divided evenly by the number of Wiegand sensors. Therefore, every time the turntable rotates, only one Wiegand sensor can detect the change in the magnetic field and generate a pulse signal. This allows multiple sensors to generate pulse signals in sequence, allowing the system to perform calculations based on these signals and execute the next control action.

[0011] Moreover, each Wiegand sensor can evenly sense the change of the magnetic field without the situation where the magnetic field strength changes too little or too much, thereby generating a continuous and stable pulse signal, which is more suitable for use in precise control systems;

[0012] This design ensures uniform magnetic field changes when the turntable rotates at high speed, making it less prone to errors and more suitable for high-resolution or fast-response applications.

[0013] Optionally, the magnet is a magnetic bar structure, and the central axis of the magnet is parallel to the central axis of the turntable.

[0014] By adopting the above technical solution, this structure of the magnet can enhance the concentration of the magnetic field, ensure that the sensor can more stably sense changes in the magnetic field at a specific angle, and improve the accuracy of position detection.

[0015] Optionally, the number of the Wiegand sensors is three, and the angle between every two adjacent Wiegand sensors is 120 degrees; the number of the magnets is ten, and the angle between every two adjacent magnets is 36 degrees.

[0016] By adopting the above technical solution, it is suitable for three-phase control of brushless motors, and the 36-degree magnet arrangement ensures sufficient magnetic field change frequency to achieve high-precision angle measurement.

[0017] Optionally, the number of the magnets is consistent with the number of driving coils in the brushless motor.

[0018] By adopting this technical solution, the number of magnets matches the number of drive coils, and the encoder's output signal is more synchronized with the motor's magnetic pole position. The encoder's output signal can accurately correspond to the switching of a magnetic pole. This synchronization allows the motor controller to more accurately estimate the actual rotor position.

[0019] Furthermore, in motor drive and control systems, control algorithms often rely on accurate rotor position feedback. If the number of encoder poles matches the number of motor drive coils, the rotor angular position can be more directly linked to the motor control signal, reducing computational complexity, optimizing control strategies, and improving response speed and dynamic performance.

[0020] Optionally, a rotating shaft is coaxially arranged on the turntable, and the rotating shaft is coaxial with the driving shaft of the brushless motor.

[0021] By adopting the above technical solutions, the coaxial design ensures that the encoder can accurately reflect the rotation of the motor shaft, reduce error accumulation, and achieve higher-precision speed and angle detection.

[0022] Optionally, both ends of the induction coil of the Wiegand sensor extend from one end of the housing of the Wiegand sensor.

[0023] By adopting the above technical solution, the internal design of the encoder can be simplified, making it convenient to centrally design the circuit board on one side of the encoder.

[0024] Optionally, the material of the magnet is neodymium iron boron / samarium cobalt / ferrite / aluminum nickel cobalt.

[0025] By adopting the above technical solutions, the selection of materials such as NdFeB, SmCo, ferrite, AlNiCo, etc. can select the most suitable magnetic material according to different application scenarios, providing different magnetic field strengths, temperature resistance and corrosion resistance.

[0026] Optionally, it also includes a signal processing circuit, a digital processor, a housing, mechanical connectors, a power supply, a communication module and a software calibration tool.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. Based on the characteristics of the Wiegand sensor, the brushless motor can achieve encoded signal output under the conditions of a purely mechanical structure. Due to the characteristics of the Wiegand sensor, the motor can also achieve stable signal output at zero speed, that is, a stable signal similar to that of magnetic encoding such as Hall, and the environmental adaptability of the rotary transformer can be obtained;

[0029] 2. The arrangement of the magnet and the Wiegand sensor allows most of the magnetic field lines to form a closed loop along the sensitive wire of the Wiegand sensor, ensuring that the Wiegand effect can be accurately triggered;

[0030] 3. Since the north and south poles of multiple magnets are arranged alternately, every time the turntable rotates, each time the sensor detects a change in magnetic poles, it can generate a clear pulse signal, thereby providing clearer pulse edges and improving signal accuracy and resolution;

[0031] 4. Each Wiegand sensor can evenly sense the change of magnetic field without the situation that the magnetic field strength changes too little or too much, thus generating a continuous and stable pulse signal, which is more suitable for use in precise control systems;

[0032] 5. The number of magnets cannot be divided evenly by the number of Wiegand sensors. Therefore, every time the turntable rotates, only one Wiegand sensor can detect the change in the magnetic field and generate a pulse signal. This allows multiple sensors to generate pulse signals in sequence, allowing the system to perform calculations based on these signals and execute the next control action.

[0033] 6. This design allows the magnetic field to change evenly when the turntable rotates at high speed, making it less prone to errors and more suitable for high-resolution or fast-response applications.

[0034] 7. The number of magnets is consistent with the number of drive coils, and the encoder output signal is more synchronized with the motor's magnetic pole position. The encoder output signal can accurately correspond to the switching of a magnetic pole. This synchronization relationship allows the motor controller to more accurately estimate the actual position of the rotor;

[0035] 8. The number of encoder poles is consistent with the number of motor drive coils, which can more directly relate the rotor angle position to the motor control signal, reduce computational complexity, optimize the control strategy, and improve response speed and dynamic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application.

[0037] Figure 2 It is a structural diagram of an embodiment of the present application used to illustrate the arrangement of magnets and Wiegand sensors.

[0038] Figure 3 This is a signal diagram used to reflect the output of the Wiegand sensor in an embodiment of the present application.

[0039] Description of the accompanying symbols: 1. turntable; 2. Wiegand sensor; 3. magnet; 4. rotating shaft. DETAILED DESCRIPTION

[0040] The following is combined with Figure 1-3 This application is described in further detail.

[0041] The embodiment of the present application discloses a brushless motor encoder based on a Wiegand sensor.

[0042] like Figure 1 and Figure 2 The brushless motor encoder based on the Wiegand sensor includes a turntable 1 and three Wiegand sensors 2. The turntable 1 is coaxially connected to the rotating shaft 4. Ten magnets 3 are embedded in the turntable 1. The number of magnets 3 is consistent with the number of driving coils in the brushless motor. In the embodiment of the present application, the magnet 3 is a rod-shaped structure. In other embodiments, the magnet 3 can be a rectangular structure. The line connecting the S-level end and the S-level end of the magnet 3 is parallel to the central axis of the rotating shaft 4, that is, in the embodiment of the present application, the central axis of the magnet 3 is parallel to the central axis of the rotating shaft 4. The ten magnets 3 are arranged equidistantly along the circumference of the turntable 1, and the angle between each two adjacent magnets 3 is 36 degrees. The magnetic poles of two adjacent magnets 3 are opposite in polarity.

[0043] The magnet material can be NdFeB / SmCo / Ferrite / AlNiCo. In this embodiment, the magnet 3 is made of NdFeB. This material has extremely high magnetic properties and is suitable for applications requiring high magnetic force. It is also compact, enabling smaller design dimensions and greater magnetic field strength. It is suitable for applications requiring high magnetic field strength, such as motors and sensors.

[0044] Three Wiegand sensors 2 are equidistantly arranged around the circumference of the turntable 1. The central axis of the sensitive wire of the Wiegand sensor 2 is parallel to the central axis of the turntable 1, meaning that the angle between each two adjacent Wiegand sensors 2 is 120 degrees. Both ends of the induction coil of the Wiegand sensor 2 extend from one end of the housing of the Wiegand sensor 2.

[0045] In such a distribution of magnets 3, most of the magnetic field lines can form a closed loop along the sensitive wire of the Wiegand sensor 2, ensuring that the Wiegand effect can be accurately triggered;

[0046] And because the N poles and S poles of the magnet 3 are arranged alternately, every time the turntable 1 rotates, each time the sensor detects a change in the magnetic poles, it can generate a clear pulse signal, thereby providing clearer pulse edges and improving the accuracy and resolution of the signal;

[0047] Moreover, each Wiegand sensor 2 can evenly sense the change of the magnetic field without the situation where the magnetic field strength changes too little or too much, thereby generating a continuous and stable pulse signal. Moreover, each Wiegand sensor 2 can generate a pulse signal in sequence, which is more suitable for use in a precise control system.

[0048] This design allows the magnetic field to change evenly when the turntable 1 rotates at high speed, making it less prone to errors. This design is more suitable for high-resolution or fast-response application scenarios.

[0049] The number of magnets 3 matches the number of drive coils, allowing the encoder's output signal to be more synchronized with the motor's magnetic pole position. The encoder's output signal can precisely correspond to the switching of a magnetic pole. This synchronization allows the motor controller to more accurately estimate the actual rotor position.

[0050] Furthermore, in motor drive and control systems, control algorithms often rely on accurate rotor position feedback. If the number of encoder poles matches the number of motor drive coils, the rotor angular position can be more directly linked to the motor control signal, reducing computational complexity, optimizing control strategies, and improving response speed and dynamic performance.

[0051] The brushless motor encoder based on Wiegand sensor 2 also includes a signal processing circuit, a digital processor, a housing, mechanical connectors, a power supply, a communication module and a software calibration tool;

[0052] The housing is used to fix the magnet 3, the turntable 1 and the Wiegand sensor 2 to ensure that they maintain accurate relative positions during the operation of the encoder;

[0053] The mechanical connector generally includes a connecting shaft and a bearing, and is connected to the motor drive shaft to ensure the synchronous rotation of the turntable 1;

[0054] The output of Wiegand sensor 2 is connected to a signal processing circuit board via a wire. The signal processing circuit board receives the pulse signal from Wiegand sensor 2 and converts it into an appropriate voltage or frequency signal. A microcontroller receives the signal from the signal processing circuit board through its input port. Based on the received pulse signal, the microcontroller performs tasks such as pulse counting, position calculation, or speed calculation. The microcontroller uses the processed data for motor control and can also transmit the data to external systems via a communication module.

[0055] The signal output state of the brushless motor encoder based on the Wiegand sensor 2 of the present application is as follows: Figure 3As shown, Wiegand sensor 2 outputs periodic positive and negative pulse signals under an alternating magnetic field. This signal logically conveys the same information as a square wave signal and can be converted into a square wave signal using a simple bistable trigger. Based on the characteristics of Wiegand sensor 2, the entire motor achieves coded signal output with a purely mechanical structure. Due to the characteristics of Wiegand sensor 2, the motor also achieves stable signal output at zero speed, achieving a stable signal from magnetic encoding such as Hall effect, while also maintaining the environmental adaptability of a resolver.

[0056] It should be noted that, in other embodiments, we can also have a variety of combinations of magnets and Wiegand sensors, as long as the following formula is satisfied: M=2k and M mod N ≠0;

[0057] M is the number of magnets, N is the number of Wiegand sensors, and k is a positive integer;

[0058] That is, the number of magnets is an even number and is not an integer multiple of the number of Wiegand sensors;

[0059] Specific examples are:

[0060] There are 12 magnets and 5 sensors, 8 magnets and 3 Wiegand sensors, or 10 magnets and 4 Wiegand sensors. The magnets are arranged equidistantly along the circumference of the turntable, and the Wiegand sensors are arranged equidistantly along the circumference of the turntable. In this way, multiple Wiegand sensors can be staggered in sequence to generate pulse signals, and the time intervals between the pulse signals are fixed and equal.

[0061] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A brushless motor encoder based on a Wiegand sensor, characterized by: The invention comprises a turntable (1) and a plurality of Wiegand sensors (2), wherein a plurality of magnets (3) are arranged equidistantly along the circumference of the turntable (1), a line connecting the N-terminal end and the S-terminal end of each magnet (3) is parallel to the central axis of the turntable (1), and the magnetic poles of two adjacent magnets (3) are opposite in polarity, a plurality of Wiegand sensors (2) are arranged around the turntable (1), a plurality of Wiegand sensors (2) are arranged equidistantly along the circumference of the turntable (1), the central axis of the sensitive wire of the Wiegand sensor (2) is parallel to the central axis of the turntable (1), the number of the magnets (3) is an even number, and the number of the magnets (3) is not an integer multiple of the number of the Wiegand sensors (2).

2. The brushless motor encoder based on Wiegand sensor according to claim 1, characterized in that: The magnet (3) is a magnetic bar structure, and the central axis of the magnet (3) is parallel to the central axis of the turntable (1).

3. The brushless motor encoder based on Wiegand sensor according to claim 1, characterized in that: The number of the Wiegand sensors (2) is three, and the angle between each two adjacent Wiegand sensors (2) is 120 degrees; the number of the magnets (3) is ten, and the angle between each two adjacent magnets (3) is 36 degrees.

4. The brushless motor encoder based on Wiegand sensor according to claim 1, characterized in that: The number of the magnets (3) is consistent with the number of driving coils in the brushless motor.

5. The brushless motor encoder based on Wiegand sensor according to claim 1, characterized in that: A rotating shaft (4) is coaxially arranged on the rotating disk (1), and the rotating shaft (4) is coaxial with the driving shaft of the brushless motor.

6. The brushless motor encoder based on Wiegand sensor according to claim 1, characterized in that: Both ends of the induction coil of the Wiegand sensor (2) extend from one end of the housing of the Wiegand sensor (2).

7. The brushless motor encoder based on Wiegand sensor according to claim 1, characterized in that: The material of the magnet (3) is neodymium iron boron / samarium cobalt / ferrite / aluminum nickel cobalt.

8. The brushless motor encoder based on Wiegand sensor according to claim 1, characterized in that: It also includes signal processing circuitry, a digital processor, a housing, mechanical connectors, a power supply, a communication module, and software calibration tools.

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