Axial flux motor

Abstract

The present invention relates to an axial flux motor, and more specifically, to an axial flux motor that can reduce vibration and noise and maximize rotational efficiency by arranging permanent magnets in a multi-stage skew manner to reduce cogging torque and torque ripple generated in the axial flux motor. To this end, the present invention is characterized by reducing cogging torque and torque ripple generated in an axial flux motor comprising an upper rotor and a lower rotor formed at the top and bottom, respectively, centered on a stator, by selecting the upper rotor permanent magnet of the upper rotor and the lower rotor permanent magnet of the lower rotor, respectively, and then applying a multi-stage skew method to either the left or right side of the upper rotor permanent magnet and the lower rotor permanent magnet.

Description

Technology Field

[0001] The present invention relates to an axial flux motor, and more specifically, to an axial flux motor that can reduce vibration and noise and maximize rotational efficiency by arranging permanent magnets in a multi-stage skew manner to reduce cogging torque and torque ripple generated in the axial flux motor. Background Technology

[0002] Generally, a motor is a device that converts electrical energy into mechanical energy to obtain rotational power, and motors are classified into AC motors and DC motors depending on the type of power source applied from the outside.

[0003] These motors operate on the principle that torque is generated in the rotor by a rotating magnetic field created when current flows through the wound coils.

[0004] Conventional motors are mostly composed of a housing, a stator fixedly coupled inside the housing, a plurality of cores installed in the stator, a plurality of coils individually wound around the coils, a permanent magnet installed facing the core and rotating by the magnetic force with the coils, and a rotor coupled with the permanent magnet and rotating.

[0005] An axial flux motor refers to a motor in which the air gap is planar and the magnetic field distribution along the axial direction is perpendicular to the plane of the air gap. Since axial flux motors possess characteristics of high torque, low weight, and high efficiency compared to radial flux motors, they are suitable for industrial fields requiring high torque density and miniaturization.

[0006] Compared to conventional radial flux motors, these axial flux motors have complex shapes due to structural characteristics in which the magnetic circuit is formed along the axial direction and the stator and rotor are arranged coaxially.

[0007] Despite the advantage of providing high torque density and efficiency relative to the same volume, these axial flux motors have a large radius of rotation and the permanent magnet and stator teeth are close together, which raises concerns about relatively large cogging torque and torque ripple.

[0008] The skew technique, a representative method to mitigate these problems, can generally offset magnetic flux imbalance and improve torque characteristics by arranging permanent magnets or slots by tilting or dividing them at a certain angle.

[0009] However, since skew techniques, which have evolved around radial flux motors, fail to adequately reflect the structural complexity of axial motors when applying only a single skew angle, the current reality requires a multi-stage skew method that assigns different skew angles to each divided segment and a permanent magnet shape suitable for the direction of rotation to maximize the skew effect. The problem to be solved

[0010] The objective of the present invention is to provide an axial flux motor that can reduce vibration and noise and maximize rotational efficiency by arranging permanent magnets in a multi-stage skew manner to reduce cogging torque and torque ripple generated in the axial flux motor. means of solving the problem

[0011] The present invention, as a means to achieve the above-mentioned purpose, comprises an axial flux motor comprising an upper rotor and a lower rotor formed at the top and bottom, respectively, centered on a stator, wherein after selecting the upper rotor permanent magnet of the upper rotor and the lower rotor permanent magnet of the lower rotor, respectively, a multi-stage skew method is applied to either the left or right side of the upper rotor permanent magnet and the lower rotor permanent magnet to reduce cogging torque and torque ripple generated in the axial flux motor, and

[0012] Bidirectional rotation is applied in which the upper rotor rotates counterclockwise and the lower rotor rotates clockwise, and the skew directions of the upper rotor permanent magnets and the lower rotor permanent magnets are positioned opposite to each other, and

[0013] The basic technical feature of its configuration is obtaining a skew effect by distributing the angles of the upper rotor permanent magnets and the lower rotor permanent magnets differently. Effects of the invention

[0014] As seen above, the present invention has the effect of reducing vibration and noise and maximizing rotational efficiency by arranging permanent magnets in a multi-stage skew manner to reduce cogging torque and torque ripple generated in an axial flux motor. Brief explanation of the drawing

[0015] FIG. 1 is a perspective view of an axial flux motor according to the present invention. FIG. 2 is a front view of an axial flux motor according to the present invention. FIG. 3 is a configuration diagram showing the skew direction of the upper rotor and the lower rotor according to the present invention. FIG. 4 is a configuration diagram showing different angles of the upper rotor and the lower rotor according to the present invention. Figure 5 is a comparison of torque ripples of AFPM for Non-Skew (Unskew) and Skew shapes. Figure 6 is a comparison of the cogging torque of AFPM for Non-Skew (Unskew) and Skew shapes. Figure 7 is a comparison of torque ripple of AFPM according to the angle of the skew shape. Fig. 8 is a comparison of torque ripple of AFPM according to the difference in angle between the upper and lower plates of the multi-stage skew. FIG. 9 is a comparison of torque ripples of AFPM according to the difference in skew directions between the upper and lower plates of the skew, whether they are the same (CW-CW) or opposite (CW-CCW). Specific details for implementing the invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be implemented in various other forms. Furthermore, in order to clearly explain the present invention, parts unrelated to the explanation in the drawings have been omitted.

[0017] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0018] FIG. 1 is a perspective view of an axial flux motor according to the present invention, FIG. 2 is a front view of an axial flux motor according to the present invention, FIG. 3 is a configuration diagram showing the skew direction of an upper rotor and a lower rotor according to the present invention, and FIG. 4 is a configuration diagram showing the angles of an upper rotor and a lower rotor distributed differently according to the present invention.

[0019] The axial flux motor (100) of the present invention is composed of an upper rotor (200) and a lower rotor (400) formed at the top and bottom, respectively, centered around a stator (300), as in the prior art, and the operating principle is the same as in the prior art. Therefore, a detailed description thereof will be omitted below.

[0020] The present invention is based on the configuration of an axial flux motor (100) as shown in FIGS. 1 to 4, which reduces cogging torque and torque ripple generated in the axial flux motor, thereby reducing vibration and noise and maximizing rotational efficiency.

[0021] Here, cogging torque refers to the torque that occurs even in a no-load state due to magnetic flux interaction between the permanent magnet and the stator teeth, and torque ripple refers to the torque in which the magnitude of the torque changes periodically during the rotation of the motor.

[0022] The basic configuration of the axial flux motor (100) according to the present invention is configured such that, after selecting the upper rotor permanent magnet (210) of the upper rotor (200) and the lower rotor permanent magnet (410) of the lower rotor (400) respectively, a multi-stage skew method is applied to either the left or right side of the upper rotor permanent magnet (210) and the lower rotor permanent magnet (410) to reduce the cogging torque and torque ripple generated in the axial flux motor (100).

[0023] In addition, when the upper rotor (200) rotates counterclockwise, the lower rotor (400) rotates clockwise, and bidirectional rotation is applied. The skew directions of the upper rotor permanent magnet (210) and the lower rotor permanent magnet (410) are positioned opposite to each other, and the angles of the upper rotor permanent magnet (210) and the lower rotor permanent magnet (410) are distributed differently to maximize the skew effect.

[0024] Below, the cogging torque and torque ripple according to changes in the shape, rotation direction, and angle of the upper rotor permanent magnet (210) and the lower rotor permanent magnet (410) are compared as follows.

[0026] Figure 5 is a comparison of the torque ripple of AFPM for Non-Skew (Unskew) and Skew shapes.

[0027] According to Figure 5, torque ripple component analysis shows that the peak-to-peak size of the Skew shape is reduced by 25% compared to the Non-Skew shape.

[0028] Non-skew max 1.83 min 1.18 = 0.65,

[0029] Skew max 1.62 min 1.13 = 0.49

[0031] Figure 6 is a comparison of the cogging torque of AFPM for Non-Skew (Unskew) and Skew shapes.

[0032] According to Figure 6, cogging torque analysis shows that the magnitude of the period deviation of the Skew shape is reduced by 26% compared to the Non-Skew shape.

[0033] Non-skew 0.27 = 0.5

[0034] Skew 0.16 = 0.37

[0036] Figure 7 is a comparison of the torque ripple of AFPM according to the angle of the skew shape.

[0037] According to Fig. 7, torque ripple component analysis shows that the peak-to-peak magnitude decreases by 17% and 26% at 5 and 7 degrees compared to 0 degrees.

[0038] 0 degrees : Max 1.79 Min 1.11 = 0.68

[0039] 5 degrees : Max 1.70 Min 1.14 = 0.56

[0040] 7 degrees : Max 1.63 Min 1.13 = 0.50

[0042] Figure 8 is a comparison of torque ripples of AFPM according to the difference in angle between the upper and lower plates of the multi-stage skew.

[0043] According to Fig. 8, torque ripple component analysis shows that the peak-to-peak magnitude at 3 and 6 degrees increased by 14% and decreased by 36% compared to 0 degrees.

[0044] 0 degrees : Max 1.63 Min 1.13 = 0.50

[0045] 3 degrees : Max 1.60 Min 1.03 = 0.57

[0046] 6 degrees : Max 1.54 Min 1.22 = 0.32

[0048] Figure 9 is a comparison of torque ripples of AFPM according to the difference in skew directions between the upper and lower plates of the skew, whether they are the same (CW-CW) or opposite (CW-CCW).

[0049] According to Fig. 9, torque ripple component analysis shows that the Peak to Peak magnitude decreases by 30% in different directions compared to the same direction.

[0050] CW-CW : Max 1.63 Min 1.13 = 0.50

[0051] CW-CCW : Max 1.46 Min 1.11 = 0.35

[0053] Although the invention has been described above with reference to embodiments, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims. Explanation of the symbols

[0054] 100 ; Axial flux motor 200 ; Upper rotor 210 ; Upper rotor permanent magnet 300 ; stator 400 ; Lower rotor 410 ; Lower rotor permanent magnet

Claims

Claim 1 An axial flux motor comprising an upper rotor and a lower rotor formed at the top and bottom, respectively, centered on a stator, characterized by reducing cogging torque and torque ripple generated in the axial flux motor by selecting the upper rotor permanent magnet of the upper rotor and the lower rotor permanent magnet of the lower rotor, respectively, and applying a multi-stage skew method to either the left or right side of the upper rotor permanent magnet and the lower rotor permanent magnet. Claim 2 An axial flux motor according to claim 1, characterized in that when the upper rotor rotates counterclockwise, bidirectional rotation is applied such that the lower rotor rotates clockwise, and the skew directions of the upper rotor permanent magnet and the lower rotor permanent magnet are positioned opposite to each other. Claim 3 An axial flux motor according to claim 1, characterized by obtaining a skew effect by distributing the angles of the upper rotor permanent magnet and the lower rotor permanent magnet differently.

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