Axial flux permanent magnet motor

Abstract

The invention provides an axial magnetic flux permanent magnet motor, which comprises a stator core, the stator core comprises a plurality of stator tooth structures arranged according to a preset arrangement mode, and each stator tooth structure is wound with a coil; the stator tooth structure comprises stator teeth and a surface structure fixedly arranged on the stator teeth. The area of the cross section of each stator tooth is gradually reduced towards the radial direction from outside to inside, and the cross section of each stator tooth is a cross section formed by wrapping a sector and a first arc and a second arc which extend along the two ends of the sector respectively, so that the perimeter of the coil is reduced through the stator tooth structure. A specific stator tooth structure is adopted, and the length of the winding is reduced under the condition that the magnetic density saturation degree is kept consistent, so that the resistance of the electrode winding is reduced, the loss of the winding is reduced, the average torque of the axial flux motor is improved, and the efficiency of the motor is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of motors, and in particular to an axial flux permanent magnet motor. Background Art

[0002] Axial flux permanent magnet motors have the advantages of compact structure, small size, light weight, and high power density. They have been widely used in many occasions with high requirements for volume or weight. The current processing technology of axial flux motor cores is mainly based on silicon steel sheet winding. The shape of the stator core made by the silicon steel sheet winding process cannot be changed at will, and there are large process limitations. The axial cross-sectional shape of the teeth of the stator core is mostly fan-shaped. The axial flux motor with fan-shaped stator teeth has low installation efficiency when installing the winding during production. The end winding length of the axial flux motor with fan-shaped stator teeth is longer, resulting in a larger phase resistance of the motor, larger winding losses during operation, and lower motor efficiency. Summary of the invention

[0003] The technical problem to be solved by the present disclosure is to provide an axial flux permanent magnet motor to overcome the defects in the prior art that the end winding length of the axial flux motor with sector-shaped stator teeth is relatively long, resulting in a larger phase resistance of the motor, larger winding losses during operation, and lower motor efficiency.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] In a first aspect, an axial flux permanent magnet motor is provided, the axial flux permanent magnet motor comprising a stator core, the stator core comprising a plurality of stator tooth structures arranged in a preset arrangement, each of the stator tooth structures being wound with a coil;

[0006] Wherein, the stator tooth structure comprises a stator tooth and a surface structure fixed to the stator tooth;

[0007] The cross-sectional area of ​​the stator tooth gradually decreases from the outside to the inside in the radial direction. The cross-sectional area of ​​the stator tooth is a sector-shaped cross-sectional area formed by a first circular arc and a second circular arc extending from both ends of the sector, so as to reduce the circumference of the coil through the stator tooth structure.

[0008] Optionally, the cross section of the stator tooth is a cross section formed by the first arc and the second arc being tangent to the boundaries at both ends of the sector;

[0009] Optionally, the cross-section of the stator tooth is pear-shaped;

[0010] The stator tooth is a columnar structure having the cross section as a cross section.

[0011] Optionally, the sector angle at the inner diameter of the sector corresponds to a first angle, and the sector angle at the outer diameter of the sector corresponds to a second angle;

[0012] Wherein, the first angle is smaller than the second angle.

[0013] Optionally, the first angle and the second angle are determined according to the following formula:

[0014]

[0015]

[0016] Among them, θ i is the first angle, θ o is the second angle, P s is the number of stator slots of the axial flux permanent magnet motor, A and B are angle parameters, and C is a constant.

[0017] Optionally, a first minimum distance between the first circular arc and the inner diameter of the motor, and a second minimum distance between the second circular arc and the outer diameter of the motor are both greater than or equal to 0 mm.

[0018] Optionally, the stator core of the axial flux permanent magnet motor is made of a soft magnetic composite material and / or the permanent magnet is a surface-mounted permanent magnet.

[0019] Optionally, the winding method of the axial flux permanent magnet motor adopts concentrated winding, and the number of turns of each winding is the same.

[0020] Optionally, the axial flux permanent magnet motor includes 10-pole permanent magnets, and the stator core includes 12 stator tooth structures.

[0021] Optionally, the first angle is 150° and the second angle is 210°.

[0022] Optionally, a coil with 224 turns is wound around each stator tooth, and four coils are connected in series to form a phase winding.

[0023] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0024] The positive progressive effect of the present disclosure lies in: adopting a specific stator tooth structure, while maintaining the same magnetic flux saturation level, reducing the length of the winding, thereby reducing the resistance of the electrode winding, reducing the loss of the winding, and improving the torque density of the motor, thereby increasing the average torque of the axial flux motor, improving the motor efficiency, and improving the installation efficiency when installing the winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of an axial flux permanent magnet motor provided by an exemplary embodiment of the present disclosure;

[0026] Figure 2 A schematic structural diagram of a stator core in an axial flux permanent magnet motor provided by an exemplary embodiment of the present disclosure;

[0027] Figure 3 An axial cross-sectional view of a sector-shaped stator tooth in an axial flux permanent magnet motor provided by an exemplary embodiment of the present disclosure;

[0028] Figure 4 An axial cross-sectional view of a pear-shaped stator tooth in an axial flux permanent magnet motor provided by an exemplary embodiment of the present disclosure;

[0029] Figure 5 A schematic diagram of no-load magnetic flux density of a sector-shaped stator tooth provided by an exemplary embodiment of the present disclosure;

[0030] Figure 6 A schematic diagram of no-load magnetic flux density of a pear-shaped stator tooth provided for an exemplary embodiment of the present disclosure;

[0031] Figure 7 A comparison diagram of no-load back electromotive force between a sector-shaped stator tooth and a pear-shaped stator tooth provided in an exemplary embodiment of the present disclosure;

[0032] Figure 8 A torque comparison diagram of a sector-shaped stator tooth and a pear-shaped stator tooth provided for an exemplary embodiment of the present disclosure;

[0033] Fig. 9 A schematic diagram of the structure of a pear-shaped stator tooth in an axial flux permanent magnet motor provided by an exemplary embodiment of the present disclosure;

[0034] Fig.10 An axial cross-sectional view of an axial flux permanent magnet motor provided according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0035] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0036] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.

[0037] Figure 1A schematic diagram of an axial flux permanent magnet motor structure is provided for an exemplary embodiment of the present disclosure, wherein the axial flux permanent magnet motor includes a stator core, the stator core includes a plurality of stator tooth structures arranged in a preset arrangement (usually evenly distributed), each stator tooth structure is wound with a coil, wherein the stator tooth structure includes a stator tooth and a surface structure fixed to the stator tooth, the cross-sectional area of ​​the stator tooth gradually decreases from the outside to the inside in a radial direction, the cross-sectional area of ​​the stator tooth is a sector-shaped cross-sectional area and a first circular arc and a second circular arc extending from both ends of the sector respectively, so as to reduce the circumference of the wound coil through the stator tooth structure.

[0038] Specifically, Figure 1 As shown, the axial flux permanent magnet motor includes a rotor core 1, a surface mounted permanent magnet 2, a winding coil 3, and a stator core 4. Figure 2 As shown, the stator core 4 includes a plurality of stator tooth structures arranged in a preset arrangement, the stator tooth structure includes a stator tooth 21 and a surface 22 structure fixed to the stator tooth, and each stator tooth structure is wound with a coil. In the existing axial flux permanent magnet motor, the following is usually used Figure 3 In the present embodiment, the cross-sectional area of ​​the stator teeth gradually decreases from the outside to the inside in the radial direction, and both ends of the cross-sectional area are tangent to the boundaries corresponding to the surface structure, so as to reduce the circumference of the winding coil through the stator tooth structure. Due to the reduction in circumference, the resistance of the motor winding is reduced, the loss of the winding is reduced, and the efficiency of the motor is improved.

[0039] In this embodiment, a specific stator tooth structure is adopted to reduce the length of the winding while maintaining the same magnetic flux saturation level, thereby reducing the resistance of the electrode winding, reducing the loss of the winding, and improving the torque density of the motor, thereby increasing the average torque of the axial flux motor, improving the motor efficiency, and improving the installation efficiency when installing the winding.

[0040] In one embodiment, the cross section of the stator tooth is a cross section formed by the first arc and the second arc being tangent to the boundaries at both ends of the sector, and the stator tooth is a columnar structure with the cross section as the cross section.

[0041] In one embodiment, the cross section of the stator tooth is pear-shaped, and the stator tooth is a columnar structure with the cross section as its cross section.

[0042] Specifically, Figure 2 The columnar structure in the middle is the stator tooth 21. Figure 4 Taking the pear-shaped structure shown in FIG. 1 as an example, the no-load magnetic flux density of the commonly used sector-shaped stator and the no-load magnetic flux density of the pear-shaped stator in this embodiment are as follows: Figure 5 and Figure 6As shown in the figure, the magnetic saturation (unit is Tesla) shows that the magnetic flux saturation of the stator teeth remains consistent when no-load, proving that when the magnetic flux passing through the teeth and the cross-sectional area of ​​the stator teeth remain unchanged, the magnetic flux density in the stator teeth remains basically unchanged, and the pear-shaped teeth have little effect on the magnetic flux saturation of the teeth. Figure 7 As shown (the vertical axis is the no-load back electromotive force, the unit is V; the horizontal axis is the rotor position electrical angle), the two are almost the same. Keep the two cross-sectional areas consistent, and keep the stator slot width and other motor parameters consistent. Calculation shows that the length of each phase winding of the sector gear motor is 80512.8mm, and the phase resistance is 11.21Ω, while the length of each phase winding of the pear gear motor is 72445.5mm, and the phase resistance is 10.09Ω, which is 10.02% smaller in comparison. Passing current to keep the copper loss of the two windings consistent, the torque comparison is Figure 8 As shown (the vertical axis is torque, the unit is mNm; the horizontal axis is the rotor position electrical angle), the average torque of the sector-tooth stator motor is 0.325Nm and the efficiency is 89.68%, and the average torque of the pear-tooth stator motor is 0.343Nm and the efficiency is 90.20%. In comparison, the torque density of the pear-tooth stator motor is increased by 5.54% and the efficiency is increased by 0.52%.

[0043] In this embodiment, a stator tooth structure formed by a cross section formed by wrapping the first arc and the second arc is adopted, which further reduces the winding resistance, improves the efficiency of the motor, and also further improves the efficiency of installing the winding.

[0044] In one embodiment, the fan angle at the inner diameter of the fan corresponds to a first angle, and the fan angle at the outer diameter of the fan corresponds to a second angle, wherein the first angle is smaller than the second angle.

[0045] Specifically, the pear-shaped tooth structure parameters are as follows: Fig. 9 As shown, the arc edge is tangent to the straight edge of the radial stator slot, and the first angle at the inner diameter of the pear-shaped stator tooth is the fan angle θ i , the second angle at the outer diameter of the pear-shaped stator tooth is the sector angle θ o , sector angle θ i Smaller than the fan angle θ o .

[0046] In one embodiment, the first angle and the second angle are determined according to the following formula:

[0047]

[0048]

[0049] Among them, θ i is the first angle, θ o is the second angle, P sis the number of stator slots of the axial flux permanent magnet motor, A and B are angle parameters, and C is a constant.

[0050] Specifically, taking an axial flux permanent magnet motor with 8 poles and 9 slots as an example, the axial flux permanent magnet motor includes 9 stator teeth. When A is 180°, B is 360°, and C is 2, the above formula is:

[0051]

[0052]

[0053] According to the above formula, the first angle θ at the inner diameter of the pear-shaped stator tooth in the axial flux permanent magnet motor with 8 poles and 9 slots is calculated as follows: i is 140°, and the second angle θ at the outer diameter of the pear-shaped stator tooth o is 220°.

[0054] In one embodiment, a first minimum distance between the first arc and the inner diameter of the motor, and a second minimum distance between the second arc and the outer diameter of the motor are both greater than or equal to 0 mm.

[0055] Specifically, Fig. 9 As shown, the stator teeth cannot extend beyond the stator surface structure, so the minimum distance h between the pear-shaped stator teeth and the inner diameter of the motor is i and the minimum distance h between the pear-shaped stator teeth and the motor outer diameter o Are both greater than or equal to 0mm.

[0056] In one embodiment, the stator core of the axial flux permanent magnet motor is a soft magnetic composite material.

[0057] In one embodiment, the permanent magnets of the axial flux permanent magnet motor are surface-mounted permanent magnets.

[0058] In one embodiment, the winding method of the axial flux permanent magnet motor adopts concentrated winding, and the number of turns of each winding is the same.

[0059] In one embodiment, Figure 1 As shown, the motor pole slot combination of the axial flux permanent magnet motor is 10 poles and 12 slots.

[0060] The structure diagram of the pear-shaped stator core is as follows: Figure 2 The iron core is made of soft magnetic composite materials and contains 12 stator teeth. A coil with 224 turns is wound around each tooth, and four coils are connected in series to form a phase winding.

[0061] The arc edge of the pear-shaped stator core is tangent to the straight edge of the radial stator slot, and the sector angle θ at the inner diameter of the pear-shaped stator tooth iis 150°, and the sector angle θ at the outer diameter of the pear-shaped stator teeth o is 210°.

[0062] The no-load magnetic flux density of the sector-shaped tooth stator and the no-load magnetic flux density of the pear-shaped tooth stator are as follows Figure 5 and Figure 6 As shown, it can be seen that the magnetic flux saturation degree of the stator teeth remains consistent when no-load, proving that when the magnetic flux passing through the teeth and the cross-sectional area of ​​the stator teeth remain unchanged, the magnetic flux density in the stator teeth remains basically unchanged, and the pear-shaped teeth have little effect on the magnetic flux saturation degree of the teeth. Figure 7 As shown, the two are almost the same. Keep the two cross-sectional areas consistent, and keep the stator slot width and other motor parameters consistent. Calculation shows that the length of each phase winding of the sector gear motor is 80512.8mm, and the phase resistance is 11.21Ω, while the length of each phase winding of the pear gear motor is 72445.5mm, and the phase resistance is 10.09Ω, which is 10.02% smaller in comparison. Passing current to keep the copper loss of the two windings consistent, the torque comparison is Figure 8 As shown, the average torque of the sector-tooth stator motor is 0.325 Nm and the efficiency is 89.68%, while the average torque of the pear-tooth stator motor is 0.343 Nm and the efficiency is 90.20%. In comparison, the torque density of the pear-tooth stator motor is increased by 5.54% and the efficiency is increased by 0.52%.

[0063] In one embodiment, the motor pole slots of the axial flux permanent magnet motor are matched to 8 poles and 9 slots, and its axial cross section is as follows: Fig.10 shown.

[0064] The iron core is pressed from soft magnetic composite materials and contains 9 stator teeth. A coil with 224 turns is wound around each tooth, and three coils are connected in series to form a phase winding.

[0065] The pear-shaped stator core structure is adopted, the arc edge is tangent to the straight edge of the radial stator slot, and the sector angle θ at the inner diameter of the pear-shaped stator tooth i is 140°, and the sector angle θ at the outer diameter of the pear-shaped stator teeth o is 220°.

[0066] The axial cross section of the pear-shaped tooth stator is as follows Fig.10 As shown in the figure, in order to show the advantages of pear-shaped teeth, the two cross-sectional areas are kept consistent, and the stator slot width and other motor parameters are kept consistent. It is calculated that the winding length of each phase of the sector-shaped gear motor is 69192.5mm, and the phase resistance is 6.17Ω, while the winding length of each phase of the pear-shaped gear motor is 61337.2mm, and the phase resistance is 5.47Ω, which are both reduced by 11.35%.

[0067] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. An axial flux permanent magnet motor, characterized in that: The axial flux permanent magnet motor comprises a stator core, wherein the stator core comprises a plurality of stator tooth structures arranged in a preset arrangement, and each of the stator tooth structures is wound with a coil; Wherein, the stator tooth structure comprises a stator tooth and a surface structure fixed to the stator tooth; The cross-sectional area of ​​the stator tooth gradually decreases from the outside to the inside in the radial direction. The cross-sectional area of ​​the stator tooth is a sector-shaped cross-sectional area formed by a first circular arc and a second circular arc extending from both ends of the sector, so as to reduce the circumference of the coil through the stator tooth structure.

2. The axial flux permanent magnet motor according to claim 1, characterized in that: The cross section of the stator tooth is a cross section formed by the first arc and the second arc being tangent to the boundaries at both ends of the sector; and / or, The cross section of the stator tooth is pear-shaped; The stator tooth is a columnar structure having the cross section as a cross section.

3. The axial flux permanent magnet motor according to claim 2, characterized in that: A first angle corresponding to the sector angle at the inner diameter of the sector, and a second angle corresponding to the sector angle at the outer diameter of the sector; Wherein, the first angle is smaller than the second angle.

4. The axial flux permanent magnet motor according to claim 3, characterized in that: The first angle and the second angle are determined according to the following formula; Among them, θ i is the first angle, θ o is the second angle, P s is the number of stator slots of the axial flux permanent magnet motor, A and B are angle parameters, and C is a constant.

5. The axial flux permanent magnet motor according to claim 2, characterized in that: A first minimum distance between the first circular arc and the inner diameter of the motor, and a second minimum distance between the second circular arc and the outer diameter of the motor are both greater than or equal to 0 mm.

6. The axial flux permanent magnet motor according to claim 1, characterized in that: The stator core of the axial flux permanent magnet motor is made of a soft magnetic composite material and / or the permanent magnet is a surface-mounted permanent magnet.

7. The axial flux permanent magnet motor according to claim 1, characterized in that: The winding method of the axial flux permanent magnet motor adopts concentrated winding, and the number of turns of each winding is the same.

8. The axial flux permanent magnet motor according to claim 3, characterized in that: The axial flux permanent magnet motor includes 10-pole permanent magnets, and the stator core includes 12 stator tooth structures.

9. The axial flux permanent magnet motor according to claim 8, characterized in that: The first angle is 150°, and the second angle is 210°.

10. The axial flux permanent magnet motor according to claim 8, characterized in that: A coil with 224 turns is wound around each stator tooth, and four coils are connected in series to form a phase winding.

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