Axial flux motor and stepping control method thereof

Abstract

The invention discloses an axial magnetic flux motor and a stepping control method thereof. Accurate control over the motor is achieved in a stepping control mode. The method comprises the following steps: acquiring operation parameters of the axial magnetic flux motor, determining an initial angle and a stepping angle of the axial magnetic flux motor, further determining a power-on period of the axial magnetic flux motor, drawing a stator excitation waveform image, generating a three-phase current for controlling the axial magnetic flux motor, and controlling the stepping rotation of the axial magnetic flux motor by utilizing a PWL function. The technical scheme has the advantage of high precision, the rotation angle and speed of the axial magnetic flux motor are accurately controlled by controlling the number and frequency of current pulses, high-precision position positioning and motion control are realized, and the axial magnetic flux motor is applicable to application occasions such as communication and data transmission holders as a driving motor.

Description

Technical Field

[0001] The present invention relates to the technical field of axial flux motors, and more specifically, to an axial flux motor and a stepping control method thereof. Background Art

[0002] With the rapid development of science and technology, industrial automation and intelligent manufacturing have become the mainstay of modern manufacturing, leading the manufacturing industry to develop in a more efficient and intelligent direction. In this context, as a key component of the power system, the performance improvement and optimization of the motor is crucial to the stable operation and efficiency improvement of the entire system. The axial flux motor has the advantages of small size, high torque, high power density, high efficiency and precise positioning. Therefore, it can be used as a drive motor for communication and data transmission pan-tilt heads. At the same time, the axial flux motor also plays a key role in the fields of precision instrument manufacturing and electric vehicles.

[0003] However, the traditional control method of axial flux motor cannot achieve accurate stepping control of axial flux motor. In order to improve the positioning and motion control accuracy of axial flux motor, the rotation angle and speed of axial flux motor can be accurately controlled by controlling the number and frequency of current pulses, which is of great significance to the optimization of axial flux motor control method. Summary of the invention

[0004] In view of this, the present invention provides an axial flux motor and a control method for the axial flux motor, so as to realize step control of the axial flux motor and effectively improve the control accuracy.

[0005] To achieve the above object, the present invention adopts the following technical solution: an axial flux motor, comprising: a housing, a stator part and a rotor part, wherein: The housing comprises a cavity, and the stator part and the rotor part are placed in the cavity; The stator part includes a stator coil and a stator core, wherein the stator core is in a disc shape and is composed of an iron disc made of a wound tape core; The rotor part includes a rotor shaft, a magnetic steel and a rotor permanent magnet, wherein the rotor shaft passes through two sides of the cavity, the rotor shaft is rotatably connected to the housing, the magnetic steel is a solid steel disk, the rotor permanent magnet is composed of a NdFeB permanent magnet material and is embedded in the solid steel disk, the magnetic steel and the rotor permanent magnet are arranged in the cavity and sleeved on the rotor shaft, and are fixedly connected to the rotor shaft; The stator coil is a ring-shaped winding made of epoxy resin material.

[0006] A stepping control method for an axial flux motor, the method comprising the following steps: S1: Acquire operating parameters of the axial flux motor, wherein the operating parameters include a rated speed, an initial angle of the motor, and a step angle of the motor; S2: according to the operating parameters of the axial flux motor, setting the power-on pulse time of the three-phase stator coil, and determining the power-on period of the axial flux motor based on the power-on pulse time of the three-phase stator coil; S3: Draw a stator excitation waveform image, and use the PWL function to set the stator excitation waveform as the excitation of the axial flux motor, determine the power-on sequence of phases A, B, and C of the axial flux motor, and then generate a three-phase current for controlling the axial flux motor.

[0007] Furthermore, the S1 includes: S11: determining an initial angle of the axial flux motor according to a power supply mode of the axial flux motor and a force balance position of a magnetic field of the axial flux motor; S12: Determine the step angle of the axial flux motor according to the number of poles and the number of stator teeth of the axial flux motor.

[0008] Further, the determining of the initial angle of the axial flux motor based on the rotational force equilibrium position of the axial flux motor comprises: Taking phase C as an example, the two adjacent teeth of the stator of the axial flux motor are phase C+ and phase C-. Since phase C+ applies counterclockwise torque to the rotor and phase C- applies clockwise torque to the rotor, when the distance between C+ and the rotor permanent magnet is the same as the distance between C- and the rotor permanent magnet, the adjacent rotor permanent magnets are subjected to the same force, which is the force balance position of the magnetic field of the axial flux motor. The rotation angle when the rotor part of the axial flux motor rotates from the initial position to the magnetic field force balance position is the initial angle.

[0009] Further, determining the step angle of the axial flux motor includes: The step angle of the axial flux motor depends on the number of poles and stator teeth of the axial flux motor. When the axial flux motor rotates by a step angle, the next phase power supply is changed. At this time, the rotor permanent magnet is required to be in a balanced position. By rotating the axial flux motor, when the axial flux motor rotates a certain angle from the initial position, the rotor permanent magnet is in the next balanced position. The rotation angle is set as the step angle of the axial flux motor.

[0010] Further, the power-on period of the axial flux motor is determined based on the power-on time of the three-phase stator coils, wherein: The rotation speed of the axial flux motor is set to obtain the angular velocity of the axial flux motor. Based on the step angle and angular velocity of the axial flux motor, the power-on time of each phase is determined according to formula (1). (1), In formula (1), is the step angle of the axial flux motor, is the angular velocity of the axial flux motor. A+ phase, A- phase, B+ phase, B- phase, C+ phase, and C- phase are powered respectively according to one power-on cycle to determine one power-on cycle of the axial flux motor.

[0011] Furthermore, the step S3 specifically includes: S31: Determine the time and value pairs required for drawing the stator excitation waveform; S32: according to the time and value pairs determined in S31, based on one power-on cycle, rectangular waves that reach peak values ​​in sequence in time and have the same duty cycle are drawn, and the stator excitation waveforms defined as the PWL function are used as the stator current excitation of the axial flux motor in one cycle; S33: Setting the PWL function as the stator excitation of the axial flux motor, determining the power-on sequence of the three phases of the axial flux motor according to the stator excitation waveform, and then obtaining the three-phase current for controlling the axial flux motor.

[0012] After adopting the above technical solution, the present invention realizes the stepping control of the axial flux motor. Compared with the prior art, the present invention has the advantages that by drawing the stator excitation waveform image, the stator excitation waveform is set as the excitation of the axial flux motor using the PWL function, and then a three-phase current for controlling the axial flux motor is generated. The rotation angle and speed of the axial flux motor are precisely controlled by controlling the number and frequency of current pulses, thereby improving the position positioning and motion control accuracy of the axial flux motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 A schematic diagram of the structure of an axial flux motor according to an embodiment of the present invention; Figure 2 This is a flow chart of the core steps of the axial flux motor control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0016] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0017] like Figure 1 As shown, an axial flux motor comprises: a housing 1, a stator part T1 and a rotor part T2, wherein: The housing 1 includes a cavity 7 ; the stator part and the rotor part are placed in the cavity, the stator part T1 includes a stator coil 2 and a stator core 3 ; the rotor part T2 includes a rotor shaft 6 , a magnetic steel 4 and a permanent magnet 5 .

[0018] Specifically, the stator core is in a disc shape and is composed of an iron disc made of a wound core; the stator coil is a ring winding made of epoxy resin material.

[0019] Specifically, the rotor shaft passes through two sides of the cavity, the rotor shaft is rotatably connected to the shell, the magnetic steel is composed of a solid steel disk, and the permanent magnet is composed of NdFeB permanent magnet material and embedded in the solid steel disk.

[0020] Specifically, the magnetic steel and the permanent magnet are arranged in the cavity and sleeved on the rotor shaft, and are fixedly connected to the rotor shaft.

[0021] Based on the axial flux motor provided in the above embodiment, the present case also provides a stepping control method for the axial flux motor, comprising the following steps: S1: Acquire operating parameters of the axial flux motor, wherein the operating parameters include a rated speed, an initial angle of the motor, and a step angle of the motor; S2: according to the operating parameters of the axial flux motor, setting the power-on pulse time of the three-phase stator coil, and determining the power-on period of the axial flux motor based on the power-on pulse time of the three-phase stator coil; S3: Based on Ansys Maxwell, the stator excitation waveform image is drawn, and the stator excitation waveform is set as the excitation of the axial flux motor using the PWL function. The power-on sequence of phases A, B, and C of the axial flux motor is determined, and then the three-phase current for controlling the axial flux motor is generated.

[0022] like Figure 2As shown, the key steps of the axial flux motor control method of this embodiment are demonstrated; The S1 includes: S11: determining an initial angle of the axial flux motor according to a power supply mode of the axial flux motor and a force balance position of a magnetic field of the axial flux motor; S12: Determine the step angle of the axial flux motor according to the number of poles and the number of stator teeth of the axial flux motor.

[0023] Specifically, the initial angle of the axial flux motor is determined based on the rotation force equilibrium position of the axial flux motor, including: Taking phase C as an example, the two adjacent teeth of the axial flux motor stator are phase C+ and phase C-. Since phase C+ applies counterclockwise torque to the rotor and phase C- applies clockwise torque to the rotor, when the distance between C+ and the rotor permanent magnet is the same as the distance between C- and the rotor permanent magnet, the adjacent rotor permanent magnets are subjected to the same force, which is the force balance position of the axial flux motor magnetic field. The rotation angle when the rotor part of the axial flux motor rotates from the initial position to the magnetic field force balance position is the initial angle.

[0024] Specifically, in step S12, the step angle of the axial flux motor is determined, wherein: The step angle of the axial flux motor depends on the number of poles and stator teeth of the axial flux motor. When the axial flux motor rotates by a step angle, the next phase power supply is changed. At this time, the rotor permanent magnet is required to be in a balanced position. By rotating the axial flux motor model, it is obtained that when the axial flux motor rotates a certain angle from the initial position, the rotor permanent magnet happens to be in the next balanced position, so the rotation angle is set as the step angle of the axial flux motor.

[0025] Specifically, in S2, the power-on period of the axial flux motor is determined based on the power-on time of the three-phase stator coils, wherein: The rotation speed of the axial flux motor is set to obtain the angular velocity of the axial flux motor. Based on the step angle and angular velocity of the axial flux motor, the power-on time T of each phase is determined according to formula (1). (1), In formula (1), is the step angle of the axial flux motor, is the angular velocity of the axial flux motor. A+ phase, A- phase, B+ phase, B- phase, C+ phase, and C- phase are powered respectively according to one power-on cycle to determine one power-on cycle of the axial flux motor.

[0026] Specifically, the S3 includes: S31: Determine the time and value pairs required for drawing the stator excitation waveform; S32: According to the time and value pairs determined in S31, in Ansys Maxwell simulation software, rectangular waves that reach peak values ​​in time sequence and have the same duty cycle are drawn based on one power-on cycle, and the stator excitation waveforms defined as the PWL function are used as the stator current excitation of the axial flux motor in one cycle; S33: Setting the PWL function as the stator excitation of the axial flux motor, determining the power-on sequence of the three phases of the axial flux motor according to the stator excitation waveform, and then obtaining the three-phase current for controlling the axial flux motor.

[0027] This embodiment energizes the three-phase stator coils in sequence, utilizes the magnetic field generated around the stator coils to interact with the magnetic field of the permanent magnets on the rotor to generate suction, and causes the rotor to rotate in steps under the action of the suction, thereby realizing step control of the axial flux motor.

[0028] This embodiment controls the number and frequency of current pulses to accurately control the rotation angle and speed of the axial flux motor, thereby achieving high-precision positioning and motion control. It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0029] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An axial flux motor, characterized in that: include: housing, a stator portion and a rotor portion, wherein The housing comprises a cavity, and the stator part and the rotor part are placed in the cavity; The stator part includes a stator coil and a stator core, wherein the stator core is in a disc shape and is composed of an iron disc made of a wound tape core; The rotor part includes a rotor shaft, a magnetic steel and a rotor permanent magnet, wherein the rotor shaft passes through two sides of the cavity, the rotor shaft is rotatably connected to the housing, the magnetic steel is a solid steel disk, the rotor permanent magnet is composed of a NdFeB permanent magnet material and is embedded in the solid steel disk, the magnetic steel and the rotor permanent magnet are arranged in the cavity and sleeved on the rotor shaft, and are fixedly connected to the rotor shaft; The stator coil is a ring-shaped winding made of epoxy resin material.

2. A stepping control method for an axial flux motor, used for controlling the axial flux motor according to claim 1, characterized in that: The method comprises the following steps: S1: Acquire operating parameters of the axial flux motor, wherein the operating parameters include a rated speed, an initial angle of the motor, and a step angle of the motor; S2: according to the operating parameters of the axial flux motor, setting the power-on pulse time of the three-phase stator coil, and determining the power-on period of the axial flux motor based on the power-on pulse time of the three-phase stator coil; S3: Draw a stator excitation waveform image, and use the PWL function to set the stator excitation waveform as the excitation of the axial flux motor, determine the power-on sequence of phases A, B, and C of the axial flux motor, and then generate a three-phase current for controlling the axial flux motor.

3. The stepping control method of the axial flux motor according to claim 1, characterized in that: The S1 includes: S11: determining an initial angle of the axial flux motor according to a power supply mode of the axial flux motor and a force balance position of a magnetic field of the axial flux motor; S12: Determine the step angle of the axial flux motor according to the number of poles and the number of stator teeth of the axial flux motor.

4. The stepping control method of the axial flux motor according to claim 3, characterized in that: The method of determining the initial angle of the axial flux motor based on the rotation force equilibrium position of the axial flux motor comprises: Taking phase C as an example, the two adjacent teeth of the stator of the axial flux motor are phase C+ and phase C-. Since phase C+ applies counterclockwise torque to the rotor and phase C- applies clockwise torque to the rotor, when the distance between C+ and the rotor permanent magnet is the same as the distance between C- and the rotor permanent magnet, the adjacent rotor permanent magnets are subjected to the same force, which is the force balance position of the magnetic field of the axial flux motor. The rotation angle when the rotor part of the axial flux motor rotates from the initial position to the magnetic field force balance position is the initial angle.

5. The stepping control method for an axial flux motor according to claim 3, characterized in that: Determine the step angle of an axial flux motor, including: The step angle of the axial flux motor depends on the number of poles and stator teeth of the axial flux motor. When the axial flux motor rotates by a step angle, the next phase power supply is changed. At this time, the rotor permanent magnet is required to be in a balanced position. By rotating the axial flux motor, when the axial flux motor rotates a certain angle from the initial position, the rotor permanent magnet is in the next balanced position. The rotation angle is set as the step angle of the axial flux motor.

6. The stepping control method for an axial flux motor according to claim 3, characterized in that: The energization period of the axial flux motor is determined based on the energization time of the three-phase stator coils, wherein: The rotation speed of the axial flux motor is set to obtain the angular velocity of the axial flux motor. Based on the step angle and angular velocity of the axial flux motor, the power-on time of each phase is determined according to formula (1). （1）， In formula (1), is the step angle of the axial flux motor, is the angular velocity of the axial flux motor. A+ phase, A- phase, B+ phase, B- phase, C+ phase, and C- phase are powered respectively according to one power-on cycle to determine one power-on cycle of the axial flux motor.

7. The stepping control method for an axial flux motor according to claim 3, characterized in that: The step S3 specifically includes: S31: Determine the time and value pairs required for drawing the stator excitation waveform; S32: according to the time and value pairs determined in S31, based on one power-on cycle, rectangular waves that reach peak values ​​in sequence in time and have the same duty cycle are drawn, and the stator excitation waveforms defined as the PWL function are used as the stator current excitation of the axial flux motor in one cycle; S33: Setting the PWL function as the stator excitation of the axial flux motor, determining the power-on sequence of the three phases of the axial flux motor according to the stator excitation waveform, and then obtaining the three-phase current for controlling the axial flux motor.

Images