Shifted built-in inclined u-shaped permanent magnet rotor
By designing a shift-type built-in tilting U-shaped permanent magnet rotor, and adopting a multi-layer U-shaped magnet assembly and an asymmetric shift structure, the problems of cogging torque vibration and noise in the built-in permanent magnet synchronous motor were solved, thereby improving motor efficiency and reducing torque fluctuation.
Patent Information
- Application Number
- CN202521768983.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-20
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-08-20
AI Technical Summary
Built-in permanent magnet synchronous motors suffer from vibration and noise problems caused by cogging torque in speed control systems, affecting low-speed performance and positioning accuracy. At the same time, they have a narrow high-speed constant power range and poor reliability.
A displacement-type built-in tilting U-shaped permanent magnet rotor is designed, which adopts a multi-layer U-shaped magnet group with inconsistent magnet widths to form an asymmetrical displacement structure, thereby reducing rotor centrifugal force, balancing radial force, optimizing magnetic flux density waveform, and reducing cogging torque fluctuation.
It effectively reduces motor noise and torque fluctuation, improves motor efficiency, reduces mechanical vibration and core loss, and optimizes magnetic flux density waveform.
Smart Images
Figure CN224683960U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of motor technology, and in particular to a technology for a displacement-type built-in tilting U-shaped permanent magnet rotor. Background Technology
[0002] Built-in permanent magnet synchronous motors have a small effective air gap, resulting in a significant impact from cogging torque. In speed control systems, when the frequency of the motor torque coincides with the mechanical resonant frequency of the stator or rotor, the vibration and noise generated by the cogging torque are significantly amplified, also affecting low-speed performance and positioning accuracy. Furthermore, drawbacks such as a narrow high-speed constant power range and poor reliability make it difficult to meet requirements.
[0003] Cogging torque, also known as reluctance torque, is a fatal flaw in speed control systems used in automated and mechatronic applications. Various methods to reduce motor torque ripple, such as fractional slot, auxiliary slot, auxiliary tooth, skewed slot, skewed pole, closed slot, and magnetized slot wedge methods, each have their advantages and disadvantages, but none are truly effective in eliminating cogging. Skewed slots or skewed poles are the most commonly used methods to reduce torque ripple, but these methods affect the air gap magnetic induction intensity and flat top width of square wave motors. Furthermore, stator skew complicates the manufacturing process and structure, reduces the stator slot area, lowers output power, and increases copper losses. Both skewed slots and skewed poles reduce output power and complicate the motor's manufacturing process and structure, increasing manufacturing costs. Utility Model Content
[0004] In view of the defects existing in the prior art, the technical problem to be solved by this utility model is to provide a shift-type built-in tilting U-shaped permanent magnet rotor that can reduce motor noise and torque fluctuation.
[0005] To solve the above-mentioned technical problems, this utility model provides a shift-type built-in tilting U-shaped permanent magnet rotor, including a rotor core, on which multiple permanent magnet units are provided. The permanent magnet units are symmetrically arranged around the axis of the rotor core. Its characteristic is that: The permanent magnet unit includes a first central horizontal magnet group, a central oblique magnet group, and two first side magnets; both the first central horizontal magnet group and the central oblique magnet group include at least two straight magnets with different widths, the straight magnets in the first central horizontal magnet group are perpendicular to the d-axis, and the straight magnets in the central oblique magnet group are inclined relative to the straight magnets in the first central horizontal magnet group; Two first side magnets are arranged symmetrically relative to the d-axis and are arranged in a narrow-mouthed inward V-shape. The first middle horizontal magnet group is arranged in the narrow mouth of the V-shape, so that the first middle horizontal magnet group and the two first side magnets form a first U-shaped magnet group. The middle oblique magnet group is arranged on the radial outer side of the first middle horizontal magnet group.
[0006] Furthermore, the permanent magnet unit also includes two second side magnets, which are respectively arranged on both sides of the d-axis and arranged in a narrow-mouthed inward figure-eight shape. The central oblique magnet group is arranged in the narrow mouth of the figure-eight shape, so that the central oblique magnet group and the two second side magnets form a second U-shaped magnet group.
[0007] Furthermore, the straight magnets in the first middle horizontal magnet group are divided into inner and outer rows along the radial direction of the rotor core, with multiple straight magnets in each row.
[0008] Furthermore, the narrow opening formed by the two second side magnets is provided with a second central horizontal magnet group. The second central horizontal magnet group is located on the radial inner side of the central oblique magnet group. The second central horizontal magnet group includes multiple straight magnets with different widths.
[0009] Furthermore, the straight-line magnets in the central oblique magnet group are divided into inner and outer rows along the radial direction of the rotor core, with multiple straight-line magnets in each row.
[0010] Furthermore, the inclination directions of the straight-line magnets in the middle oblique magnet groups of adjacent permanent magnet units are opposite.
[0011] The displacement-type built-in tilting U-shaped permanent magnet rotor provided by this utility model is equipped with a multi-layer U-shaped magnet group. The transverse side uses straight magnets with different widths, which together with the rotor core form displacement block permanent magnet poles, creating an asymmetrical displacement on the d-axis. At the same time, the central tilting magnet group is asymmetrically tilted on the d-axis, forming a double asymmetrical displacement effect of the magnetic poles on the d-axis. This can reduce the rotor centrifugal force, reduce the torque fluctuation caused by tooth cogging, and make the radial force of the d-axis of the magnetic pole radial center line and the q-axis of the inter-pole center line tend to be balanced. This reduces mechanical vibration, noise and back EMF harmonics, reduces core loss, optimizes the magnetic flux density waveform, and reduces torque fluctuation. Attached Figure Description
[0012] Figure 1 This is a radial cross-sectional schematic diagram of the shift-type built-in tilting U-shaped permanent magnet rotor of the first embodiment of this utility model; Figure 2 This is a radial cross-sectional schematic diagram of the shift-type built-in tilting U-shaped permanent magnet rotor of the second embodiment of this utility model; Figure 3 This is a radial cross-sectional schematic diagram of the shift-type built-in tilting U-shaped permanent magnet rotor according to the third embodiment of this utility model; Figure 4 This is a radial cross-sectional schematic diagram of the shift-type built-in tilting U-shaped permanent magnet rotor according to the fourth embodiment of this utility model. Detailed Implementation
[0013] The embodiments of this utility model are described in further detail below with reference to the accompanying drawings. However, these embodiments are not intended to limit this utility model. Any similar structures or variations thereof that adopt this utility model should be included in the protection scope of this utility model. The commas in this utility model all indicate the relationship between and.
[0014] like Figure 1 As shown, the first embodiment of this utility model provides a displacement-type built-in tilting U-shaped permanent magnet rotor, including a rotor core 5, on which a plurality of permanent magnet units are provided, and each permanent magnet unit is symmetrically arranged around the axis of the rotor core 5. The permanent magnet unit includes a first central horizontal magnet group 11, a central oblique magnet group 12, two first side magnets 13, and two second side magnets 15; the first central horizontal magnet group 11 and the central oblique magnet group 12 each include at least two straight magnets with different widths, the straight magnets in the first central horizontal magnet group 11 are perpendicular to the d-axis, and the straight magnets in the central oblique magnet group 12 are inclined relative to the straight magnets in the first central horizontal magnet group 11; Two first side magnets 13 are arranged symmetrically relative to the d-axis and are arranged in a narrow-mouthed inward V-shape. The first middle horizontal magnet group 11 is arranged in the narrow mouth of the V-shape, so that the first middle horizontal magnet group 11 and the two first side magnets 13 form a first U-shaped magnet group. The middle oblique magnet group 12 is arranged on the radial outside of the first middle horizontal magnet group 11. Each first side magnet 13 has an air permanent magnet groove 14 at both its inner and outer ends. Two second side magnets 15 are respectively arranged on both sides of the d-axis and arranged in a narrow-mouthed inward figure-eight shape. The middle oblique magnet group 12 is arranged in the narrow mouth of the figure-eight shape, so that the middle oblique magnet group 12 and the two second side magnets 15 form a second U-shaped magnet group. Each second side magnet 15 has an air permanent magnet groove 16 at both its inner and outer ends. The straight magnets in the first middle horizontal magnet group 11 are divided into inner and outer rows along the radial direction of the rotor core 5, and multiple straight magnets are arranged in each row.
[0015] like Figure 2 As shown, the permanent magnet unit of the second embodiment of this utility model also includes a first central horizontal magnet group 21, a central oblique magnet group 22, and two first side magnets 23 and two second side magnets 25; the structure and arrangement of the first central horizontal magnet group 11, the central oblique magnet group 12, the first side magnets 23, and the second side magnets 25 are similar to those of the first embodiment; The difference between the second embodiment of this utility model and the first embodiment is that: the narrow opening of the figure-eight shape formed by the two second side magnets 25 is provided with a second middle horizontal magnet group 27, which is located on the radial inner side of the middle oblique magnet group 22, and the second middle horizontal magnet group 27 includes a plurality of straight magnets with different widths.
[0016] like Figure 3 As shown, the permanent magnet unit of the third embodiment of this utility model also includes a first central horizontal magnet group 31, a central oblique magnet group 32, and two first side magnets 33 and two second side magnets 35; the structure and arrangement of the first central horizontal magnet group 31, the central oblique magnet group 32, the first side magnets 33, and the second side magnets 35 are similar to those of the first embodiment; The difference between the third embodiment of this utility model and the first embodiment is that the straight magnets in the central oblique magnet group 32 are divided into inner and outer rows along the radial direction of the rotor core, and multiple straight magnets are arranged in each row.
[0017] like Figure 4 As shown, the permanent magnet unit of the fourth embodiment of this utility model also includes a first central horizontal magnet group 41, a central oblique magnet group 42, and two first side magnets 43 and two second side magnets 45; the difference between the fourth embodiment and the first embodiment is that it also includes a second central horizontal magnet group 47, a third central horizontal magnet group 48, and two third side magnets 49; the second central horizontal magnet group 47 and the third central horizontal magnet group 48 each include multiple straight magnets of different widths, and the first central horizontal magnet group 45... 1. The second middle horizontal magnet group 47 and the third middle horizontal magnet group 48 are arranged in sequence from the inside to the outside along the radial direction of the rotor core. The first middle horizontal magnet group 41 is arranged in the narrow opening of the figure-eight shape formed by the two first side magnets 43. The second middle horizontal magnet group 47 is arranged in the narrow opening of the figure-eight shape formed by the two second side magnets 45. The third middle horizontal magnet group 48 is arranged in the narrow opening of the figure-eight shape formed by the two third side magnets 49. The inclination direction of the straight magnets in the middle oblique magnet groups of adjacent permanent magnet units is opposite.
[0018] The permanent magnet rotor motor of this embodiment was compared with the existing built-in permanent magnet synchronous motor of the same specification. The parameters of the existing built-in permanent magnet synchronous motor are: rated power of 20KW, rated current of 19.5A, efficiency of 94.2%, rated speed of 3000r / min, maximum speed of 6500r / min, rated torque of 63.6Nm, and maximum torque of 78Nm. Compared with existing permanent magnet rotor motors of the same specifications, the motor using the permanent magnet rotor of the first embodiment of this utility model has an efficiency that increases from 94.2% to 95.6%, a cogging torque that decreases from 3.75 Nm to 1.38 Nm, and a cogging torque fluctuation that decreases from 5.9% to 2.16%. Compared with existing permanent magnet rotor motors of the same specifications, the motor using the permanent magnet rotor of the second embodiment of this utility model has an efficiency that increases from 94.2% to 96.2%, a cogging torque that decreases from 3.75 Nm to 1.32 Nm, and a cogging torque fluctuation that decreases from 5.9% to 2.08%. Compared with existing permanent magnet rotor motors of the same specifications, the motor using the permanent magnet rotor of the third embodiment of this utility model has an efficiency that increases from 94.2% to 95.8%, a cogging torque that decreases from 3.75 Nm to 1.28 Nm, and a cogging torque fluctuation that decreases from 5.9% to 2.00%. Compared with existing permanent magnet rotor motors of the same specifications, the motor using the permanent magnet rotor of the fourth embodiment of this utility model has an efficiency that increases from 94.2% to 96.3%, a cogging torque that decreases from 3.75 Nm to 1.22 Nm, and a cogging torque fluctuation that decreases from 5.9% to 1.92%. Therefore, the present invention improves the air gap flux density waveform and reduces motor noise and torque fluctuation.
Claims
1. A shift-type built-in tilting U-shaped permanent magnet rotor, comprising a rotor core, wherein a plurality of permanent magnet units are provided on the rotor core, and the permanent magnet units are symmetrically arranged around the axis of the rotor core, characterized in that: The permanent magnet unit includes a first central horizontal magnet group, a central oblique magnet group, and two first side magnets; both the first central horizontal magnet group and the central oblique magnet group include at least two straight magnets with different widths, the straight magnets in the first central horizontal magnet group are perpendicular to the d-axis, and the straight magnets in the central oblique magnet group are inclined relative to the straight magnets in the first central horizontal magnet group; Two first side magnets are arranged symmetrically relative to the d-axis and are arranged in a narrow-mouthed inward V-shape. The first middle horizontal magnet group is arranged in the narrow mouth of the V-shape, so that the first middle horizontal magnet group and the two first side magnets form a first U-shaped magnet group. The middle oblique magnet group is arranged on the radial outer side of the first middle horizontal magnet group.
2. The shift-type built-in tilting U-shaped permanent magnet rotor according to claim 1, characterized in that: The permanent magnet unit also includes two second side magnets, which are respectively arranged on both sides of the d-axis and arranged in a figure-eight shape with the narrow opening facing inward. The central oblique magnet group is arranged in the narrow opening of the figure-eight shape, so that the central oblique magnet group and the two second side magnets form a second U-shaped magnet group.
3. The shift-type built-in tilting U-shaped permanent magnet rotor according to claim 2, characterized in that: The straight magnets in the first middle horizontal magnet group are divided into inner and outer rows along the radial direction of the rotor core, with multiple straight magnets in each row.
4. The shift-type built-in tilting U-shaped permanent magnet rotor according to claim 2 or 3, characterized in that: The narrow opening formed by the two second side magnets is provided with a second middle horizontal magnet group. The second middle horizontal magnet group is located on the radial inner side of the middle oblique magnet group. The second middle horizontal magnet group includes multiple straight magnets with different widths.
5. The shift-type built-in tilting U-shaped permanent magnet rotor according to claim 2 or 3, characterized in that: The straight magnets in the central inclined magnet group are divided into inner and outer rows along the radial direction of the rotor core, with multiple straight magnets in each row.
6. The shift-type built-in tilting U-shaped permanent magnet rotor according to claim 1, characterized in that: The inclination directions of the straight-line magnets in the middle of the adjacent permanent magnet units are opposite.