Segmented skewed pole motor rotor structure and motor comprising same

Abstract

The invention discloses a segmented skewed pole motor rotor structure and a motor comprising the same, the rotor structure comprises a plurality of rotor core sections, and the adjacent rotor core sections are staggered by a certain angle along the circumferential direction. And if the circumferential position angle of any rotor core section is taken as a reference, the circumferential skewed pole angle of each rotor core section is defined, the circumferential skewed pole angles of all the rotor core sections are arranged in a sequence from small to large, and the arranged angles do not need to be an arithmetic progression. According to the scheme, the skewed pole angle sequence does not need equal difference distribution and axial symmetry, the amplitude and phase of the electromagnetic force generated by each rotor core section can be independently designed by setting the circumferential skewed pole angle of each rotor core section, the influence caused by non-uniform axial distribution of the structural modal shape of the stator or the rotor is effectively compensated, and the stability of the stator or the rotor is improved. And the suppression effect of the segmented skewed pole rotor structure on vibration noise is improved.

Description

Technical Field

[0001] This invention relates to a motor rotor structure, belonging to the field of motor technology. Background Technology

[0002] Permanent magnet brushless motors, especially those used in electric vehicles, face significant electromagnetic vibration and noise problems due to their complex electromagnetic forces, harmonics, and low-order modes. Segmented skewed-pole motor rotor structures are widely used to suppress motor back EMF harmonics, cogging torque, torque pulsation, and vibration and noise caused by electromagnetic forces.

[0003] The paper "Blum J, Merwerth J, Herzog H G. Investigation of the segment orderin step-skewed synchronous machines on noise and vibration [C]. In: 2014 4th International Electric Drives Production Conference. Nuremberg, Germany: IEEE, 2014" proposes that the uneven axial distribution of structural mode shapes leads to differences in the vibration and noise suppression effects of different motor rotor skew pole configurations. However, it only analyzes conventional skew pole configurations such as linear skew poles and V-shaped skew poles.

[0004] CN 111769670 A proposes a segmented skewed-pole motor rotor core and a permanent magnet synchronous motor. Each segment of the rotor core uses different auxiliary slot shapes and positions to suppress torque pulsation and electromagnetic force. However, this structure does not consider the axial distribution differences of the structural modes.

[0005] CN 113300514 B proposes a permanent magnet synchronous motor with non-uniformly segmented rotor poles and its optimization method. It suppresses torque pulsation and axial unbalanced magnetic pull through non-uniform skewed poles. However, since all rotor segments are axially symmetrically distributed, it cannot compensate for the influence of the non-uniform axial distribution of structural mode vibration modes.

[0006] In summary, existing rotor skew methods have limitations in suppressing electromagnetic noise and cannot accurately and effectively compensate for the effects of uneven axial distribution of structural mode shapes. Summary of the Invention

[0007] The technical problem to be solved by this invention is: addressing the shortcomings of existing permanent magnet brushless motor rotor structures in suppressing motor back EMF harmonics, cogging torque, torque pulsation, and electromagnetic vibration noise, especially the inability to accurately and effectively compensate for the electromagnetic force imbalance caused by the uneven distribution of stator or rotor structure mode modes along the axial direction. This invention proposes a segmented skewed-pole rotor core structure that can independently control the amplitude and phase of the electromagnetic force generated by each segment of the rotor, thereby improving the electromagnetic noise suppression effect.

[0008] To solve the above technical problems, the present invention adopts the following technical solution: First, this invention proposes a segmented skew-pole motor rotor core structure, the rotor core structure comprising: The rotor core segments are arranged sequentially along the motor axis, with adjacent rotor core segments being staggered relative to each other in the circumferential direction; each rotor core segment is formed by stacking multiple rotor laminations. The circumferential skew angle and axial thickness of each rotor core segment are set independently, thereby changing the amplitude and phase of the electromagnetic force generated by each rotor core segment on the stator and rotor, so that the generalized forces generated by different segments cancel each other out in amplitude and phase.

[0009] Furthermore, the segmented skew-pole motor rotor core structure proposed in this invention assigns each rotor core segment from 1 to 1 according to its axial position. Numbering, electromagnetic force at the response point The resulting vibration displacement response is: , in, It is the modal order. For motor stator / rotor First-order modal stiffness, For motor stator / rotor First-order modal mass, It is the stator / rotor of the motor. First-order modal damping, yes Point corresponding Mode shape values ​​of the first mode. It is the angular frequency of the electromagnetic force. It is the imaginary unit. It is the maximum modal order considered after modal truncation. It refers to the number of segments in the rotor core. It is a generalized force. It is angular frequency.

[0010] Furthermore, the segmented skew-pole motor rotor core structure proposed in this invention, based on the axial coordinate, divides the first segmented skew-pole rotor core into segments with ... The axial coordinate range covered by each rotor core segment is defined as follows: The axial coordinate ranges of each rotor core segment correspond to: , … By setting the axial coordinate range of each rotor segment The amplitude and phase of the electromagnetic force generated internally on the stator / rotor are adjusted to compensate for the uneven axial distribution of the mode amplitude of the stator / rotor structure.

[0011] Furthermore, the segmented skew-pole motor rotor core structure proposed in this invention, wherein the first... The radial, tangential, and axial electromagnetic forces generated by each rotor core segment are represented by column vectors. , , Its dimension is equal to the number of nodes, and each element is the electromagnetic force phasor at each node. Axial coordinate range The radial, tangential, and axial mode shapes of the inner stator / rotor structure are represented by column vectors. , , Its dimension is equal to the number of nodes, and each element is the mode shape value at each node; electromagnetic force and generalized force generated by mode shapes. The calculation is as follows: ,in T represents the transpose, resulting in the generalized force generated by each rotor core segment. It is a phasor.

[0012] When suppressing vibration noise generated by electromagnetic forces acting on the motor stator, the structural mode shape column vector , , The column vector of mode shapes on the specified sub-core, the column vector of electromagnetic force , , Specify the column vector of electromagnetic forces on the sub-core; When suppressing the vibration noise generated by the electromagnetic force acting on the rotor magnet of the motor, the structural mode shape quantity , , The electromagnetic force column vector , , The electromagnetic force column vector on the rotor magnet; When suppressing the vibration noise generated by the electromagnetic force acting on the motor rotor core, the structural mode shape column vector , , The electromagnetic force column vector , , The electromagnetic force vector on the rotor core.

[0013] Furthermore, the segmented skew-pole motor rotor core structure proposed in this invention uses the circumferential position angle of the first rotor core segment as a reference. , will the The circumferential angular difference between the first rotor core segment and the first rotor core segment is defined as the... Circumferential skew angle of each rotor core segment ; The circumferential skew angle of all rotor core segments { , , , …, Rearrange the values ​​in ascending order, repeating the values ​​once. Given the uneven axial distribution of the mode shape amplitudes in the stator / rotor structure, the mode shapes ( , , In each axial coordinate range The amplitudes are not equal; the electromagnetic force is changed by independently controlling the skew angle of each rotor core section. , , The phase of the phase further alters the generalized force generated by each rotor core segment. The phase of the phase makes the sum of the generalized forces of all rotor core segments equal. To obtain a zero value or the minimum amplitude.

[0014] Furthermore, the present invention proposes a segmented skew-pole motor rotor core structure. , , In each axial coordinate range The amplitude values ​​are not equal; by independently controlling the stacking thickness of each rotor core section, the electromagnetic force is changed. , , The amplitude further alters the generalized force generated by each rotor core segment. The amplitude of the sum of the generalized forces in all rotor core segments is such that... To obtain a zero value or the minimum amplitude.

[0015] Furthermore, the segmented skewed-pole motor rotor core structure proposed in this invention simultaneously optimizes the skew angle and stacking thickness of each rotor core segment, thereby changing the generalized force generated by each rotor core segment. The amplitude and phase of the sum of the generalized forces in all rotor core segments are such that... To obtain a zero value or the minimum amplitude.

[0016] Meanwhile, this invention proposes an internal rotor motor that adopts the segmented skew-pole motor rotor core structure described above.

[0017] Finally, the present invention also proposes an external rotor motor that adopts the segmented skew-pole motor rotor core structure described above.

[0018] The present invention adopts the above technical solution and has the following technical effects compared with the prior art: Existing technologies do not consider the axial non-uniformity of mode shapes, and their rotor skew angles are generally an arithmetic sequence or axially centrally symmetrical. However, this invention considers the non-uniformity of axial modes, uses generalized force as the optimization target, and achieves the minimization of generalized force by independently setting the circumferential skew angle and axial thickness of any rotor core segment, and precisely controlling the phase and amplitude of the electromagnetic force generated by that segment. Its rotor skew angle sequence does not need to be arithmetic or axially symmetrical, and has a large degree of design freedom. It can perform customized compensation for the uneven distribution of stator or rotor structure mode shapes along the axial direction, so that the distribution and phase of electromagnetic forces in different segments in the axial direction are more in line with the target cancellation effect.

[0019] Specifically, when the axial distribution of the mode shape amplitudes of the stator / rotor structure is uneven, the mode shape ( , , In each axial coordinate range The amplitudes are not equal. By independently controlling the skew angle of each rotor core section, the electromagnetic force is changed. , , The phase of the phase further alters the generalized force generated by each rotor core segment. The phase; by independently controlling the stacking thickness of each rotor core segment, the electromagnetic force is changed. , , The amplitude further alters the generalized force generated by each rotor core segment. The amplitude. By adjusting the amplitude and phase of the generalized force mentioned above in each rotor core segment, or by adjusting both simultaneously, the sum of the generalized forces in all rotor core segments is made so that... Achieving the minimum amplitude or zero value improves the suppression effect of vibration noise.

[0020] Therefore, the segmented skew-pole motor rotor structure proposed in this invention is easy to apply flexibly under different motor specifications and operating conditions. Without significantly increasing manufacturing complexity and cost, it can significantly improve the vibration and noise performance of the motor. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the rotor structure of a segmented skew-pole motor.

[0022] Figure 2 This is a schematic diagram defining the circumferential skew angle of each rotor core segment.

[0023] Figure 3 This is the stator mode shape diagram of the motor. The values ​​in the diagram represent the magnitude of the mode shape at each location.

[0024] Figure 4 It is a generalized force generated by the interaction of the rotor core segments and structural modes in a conventional segmented skewed-pole motor.

[0025] Figure 5 It refers to the circumferential skew angle of each rotor core segment proposed in this invention.

[0026] Figure 6 It is the generalized force generated by the interaction of each rotor segment and structural mode proposed in this invention.

[0027] Wherein: 1~5 are the 1st~5th rotor core segments respectively; 6 is the motor stator housing; 7 is the motor stator core; 8 is the motor end cover; ~ These are the generalized forces generated by the first to fifth rotor core segments, ~ The angle difference represents the time phase of the generalized force generated in each segment. ~ The length represents the amplitude of the generalized force generated by each segment. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] This invention proposes a segmented skew-pole motor rotor structure, wherein the rotor core structure consists of... It consists of rotor core segments arranged sequentially along the motor axis. The integer is greater than or equal to 2, and the rotor core segments are sequentially numbered from segment 1 to segment 2 according to their axial position. part; The resulting vibration displacement response is: , in, It is the modal order. For motor stator / rotor First-order modal stiffness, For motor stator / rotor First-order modal mass, It is the stator / rotor of the motor. First-order modal damping, yes Point corresponding Mode shape values ​​of the first mode. It is the angular frequency of the electromagnetic force. It is the imaginary unit. It is the maximum modal order considered after modal truncation. It refers to the number of segments in the rotor core. It is a generalized force. It is angular frequency.

[0030] Two adjacent rotor core segments are offset relative to each other by a predetermined oblique pole angle in the circumferential direction. Each rotor core segment is formed by stacking multiple rotor laminations, and the total axial thickness of each rotor core segment may not be equal. By changing the amplitude and phase of the electromagnetic force generated by each rotor core segment on the stator and rotor, the generalized forces generated by different segments cancel each other out in amplitude and phase.

[0031] Using the circumferential position angle of the first rotor core segment as a reference , will the The circumferential angular difference between the first rotor core segment and the first rotor core segment is defined as the... Circumferential skew angle of each rotor core segment ,and The circumferential skew angle of all rotor core sections can be set independently. , , , …, After arranging the values ​​in ascending order, it is not required that they form an arithmetic sequence, that is, the following equations are not required to hold true: The circumferential skew angle of the arrangement is not required to be symmetrical along the axial center; that is, the following equations are not required to hold: , , .

[0032] The axial thickness of each rotor core segment By changing the number of rotor laminations Independently set, defined according to the axial coordinate. The axial coordinate range covered by each rotor core segment Number of rotor laminations in each rotor core section axial thickness of each rotor core section Equality is not required. Furthermore, the segmented skew-pole motor rotor core structure proposed in this invention, based on the axial coordinate, divides the first... The axial coordinate range covered by each rotor core segment is defined as follows: The axial coordinate ranges of each rotor core segment correspond to: , … By setting the axial coordinate range of each rotor segment The amplitude and phase of the electromagnetic force generated internally on the stator / rotor are adjusted to compensate for the uneven axial distribution of the mode amplitude of the stator / rotor structure.

[0033] Through independent settings and Each rotor segment can be controlled separately within the axial coordinate range. The radial, tangential, and axial electromagnetic forces generated internally are oriented in the direction of , , The phase and amplitude are adjusted to regulate the electromagnetic force acting on the stator / rotor in that segment, and this is combined with the radial, tangential, and axial mode shape column vectors of the stator / rotor structural modes. , , Calculate its generalized force ; When suppressing vibration noise generated by electromagnetic forces acting on the motor stator, the structural mode shape column vector , , The column vector of mode shapes on the specified sub-core, the column vector of electromagnetic forces , , Specify the column vector of electromagnetic forces on the sub-core; When suppressing the vibration noise generated by the electromagnetic force acting on the rotor magnet of the motor, the structural mode shape quantity , , The electromagnetic force column vector refers to the mode shape column vector on the rotor magnet. , , The electromagnetic force column vector on the rotor magnet; When suppressing the vibration noise generated by the electromagnetic force acting on the motor rotor core, the structural mode shape column vector , , The electromagnetic force column vector refers to the mode shape column vector on the rotor core. , , The electromagnetic force vector on the rotor core.

[0034] Through optimized design and Combination enables the generalized forces generated by different segments. The amplitude and phase cancel each other out, thereby effectively reducing vibration and noise during motor operation and realizing the generalized force generated by each rotor core section. The offsetting effect makes The modulus is equal to zero or approaches the minimum.

[0035] Example 1: This embodiment of the invention discloses a segmented skew-pole motor rotor core, such as... Figure 1 As shown, the rotor core consists of five rotor core segments. Figure 2 As shown, taking the circumferential angle of the first rotor core segment as a reference, the circumferential skew angles of the five rotor core segments are defined as follows: ~ .

[0036] This invention takes the suppression of vibration noise generated by the interaction between the electromagnetic force at 96 times the rotational frequency on the stator core of a motor with 48 stator slots and 32 rotor poles and the 0th order structural mode of the stator as an example. Figure 3 As shown, the magnitude of the structural mode shape of the motor stator core is along the axial direction ( The axial coordinate range covered by the rotor core segment is unevenly distributed. , , , , Inner mode along As the amplitude increases, the proportion of its 0th-order structural mode amplitude is: The amplitude of the 0th-order structural mode can be expressed as , , , ,and ,in This is the scaling factor for the modal shape.

[0037] To suppress the vibration noise generated by the interaction between the 96 times rotational frequency electromagnetic force on the stator core and the stator's 0th order structural mode, the circumferential skew angle of the traditional skewed pole method is... , , , …, Arranged from smallest to largest, they form an arithmetic sequence with a difference of 0.75 degrees. The phase difference between the electromagnetic force of each rotor core segment and the generalized force generated by the 0th-order mode is as follows: Figure 4 As shown, ~ The phases differ by 72 degrees. This is combined with the amplitude of the 0th-order structural mode. , , , and Therefore, after the generalized forces are superimposed The amplitude is approximately Therefore, the resulting vibration response is not zero, and it is impossible to completely suppress the vibration noise generated by the interaction between the 96 times frequency electromagnetic force on the stator core of the motor and the 0th order structural mode of the stator.

[0038] The circumferential skew angle of each rotor core segment in this invention , , , , The numbers arranged from smallest to largest do not form an arithmetic sequence, meaning the circumferential skew angles of each rotor core segment are... Designed independently. For example... Figure 5 As shown, , , The generalized force generated by the interaction between the 96-fold frequency electromagnetic force on the stator core of the motor and the 0th-order structural mode of the stator. ~ The phase difference is no longer equal, reference Figure 6 As shown, the values ​​are 79.7. 80.9 69.4 63.0 With 67 Combining the amplitude of the 0th order structural mode , , , and At this point, the generalized forces generated by the five rotor core segments are superimposed. The amplitude is approximately equal to Compared to the traditional oblique pole generalized force amplitude, it reduces This almost completely suppresses the vibration noise generated by the interaction between the 96 times frequency electromagnetic force on the stator core of the motor and the 0th order structural mode of the stator.

[0039] Example 2: This invention proposes an internal rotor motor, employing the segmented skew-pole motor rotor core structure proposed in Example 1. Technical details not described in detail in this example can be found in Example 1.

[0040] Example 3: The present invention also proposes an external rotor motor, which adopts the segmented skew-pole motor rotor core structure proposed in Example 1. Technical details not described in detail in this example can be found in Example 1.

[0041] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A segmented skew-pole motor rotor core structure, characterized in that, The rotor core structure includes The rotor core segments are arranged sequentially along the motor axis, with adjacent rotor core segments being staggered relative to each other in the circumferential direction; each rotor core segment is formed by stacking multiple rotor laminations. The circumferential skew angle and axial thickness of each rotor core segment are set independently, thereby changing the amplitude and phase of the electromagnetic force generated by each rotor core segment on the stator and rotor, so that the generalized forces generated by different segments cancel each other out in amplitude and phase.

2. The segmented skew-pole motor rotor core structure according to claim 1, characterized in that, Each rotor core segment is assigned a number from 1 to 1 according to its axial position. Numbering, electromagnetic force at the response point The resulting vibration displacement response is: ， in, It is the modal order. For motor stator / rotor First-order modal stiffness, For motor stator / rotor First-order modal mass, It is the stator / rotor of the motor. First-order modal damping, yes Point corresponding Mode shape values ​​of the first mode. It is the angular frequency of the electromagnetic force. It is the imaginary unit. It is the maximum modal order considered after modal truncation. It refers to the number of segments in the rotor core. It is a generalized force. It is angular frequency.

3. The segmented skew-pole motor rotor core structure according to claim 1, characterized in that, Based on the axial coordinate, the first The axial coordinate range covered by each rotor core segment is defined as follows: The axial coordinate ranges of each rotor core segment correspond to: , … By setting the axial coordinate range of each rotor segment The amplitude and phase of the electromagnetic force generated internally on the stator / rotor are adjusted to compensate for the uneven axial distribution of the mode amplitude of the stator / rotor structure.

4. The segmented skew-pole motor rotor core structure according to any one of claims 1 to 3, characterized in that, The first The radial, tangential, and axial electromagnetic forces generated by each rotor core segment are represented by column vectors. , , Its dimension is equal to the number of nodes, and each element is the electromagnetic force phasor at each node, with an axial coordinate range. The radial, tangential, and axial mode shapes of the inner stator / rotor structure are represented by column vectors. , , Its dimension is equal to the number of nodes, and each element is the mode shape value at each node; electromagnetic force and generalized force generated by mode shapes. The calculation is as follows: The superscript T indicates transpose, and the generalized force generated by each rotor core segment is obtained. It is a phasor.

5. The segmented skew-pole motor rotor core structure according to claim 4, characterized in that, When suppressing vibration noise generated by electromagnetic forces acting on the motor stator, the structural mode shape column vector , , The column vector of mode shapes on the specified sub-core, the column vector of electromagnetic force , , Specify the column vector of electromagnetic forces on the sub-core; When suppressing the vibration noise generated by the electromagnetic force acting on the rotor magnet of the motor, the structural mode shape quantity , , The electromagnetic force column vector refers to the mode shape column vector on the rotor magnet. , , The electromagnetic force column vector on the rotor magnet; When suppressing the vibration noise generated by the electromagnetic force acting on the rotor core of the motor, the structural mode shape column vector , , The electromagnetic force column vector refers to the mode shape column vector on the rotor core. , , The electromagnetic force vector on the rotor core.

6. The segmented skew-pole motor rotor core structure according to claim 4, characterized in that, Using the circumferential position angle of the first rotor core segment as a reference , will the The circumferential angular difference between the first rotor core segment and the first rotor core segment is defined as the... Circumferential skew angle of each rotor core segment ; The circumferential skew angle of all rotor core segments { , , , …, Rearrange the values ​​in ascending order, repeating the values ​​once. Given the uneven axial distribution of the mode shape amplitudes in the stator / rotor structure, the mode shapes ( , , In each axial coordinate range The amplitudes are not equal; the electromagnetic force is changed by independently controlling the skew angle of each rotor core section. , , The phase of the phase further alters the generalized force generated by each rotor core segment. The phase of the phase makes the sum of the generalized forces of all rotor core segments equal. To obtain a zero value or the minimum amplitude.

7. The segmented skew-pole motor rotor core structure according to claim 4, characterized in that, When the axial distribution of the mode amplitudes of the stator / rotor structure is non-uniform, the mode shapes ( , , In each axial coordinate range The amplitude values ​​are not equal; by independently controlling the stacking thickness of each rotor core section, the electromagnetic force is changed. , , The amplitude further alters the generalized force generated by each rotor core segment. The amplitude of the sum of the generalized forces in all rotor core segments is such that... To obtain a zero value or the minimum amplitude.

8. A segmented skew-pole motor rotor core structure according to claims 6-7, characterized in that, By simultaneously using the skew angle and stack thickness of each rotor core segment as optimization variables, the generalized force generated by each rotor core segment is changed simultaneously. The amplitude and phase of the sum of the generalized forces in all rotor core segments are such that... To obtain a zero value or the minimum amplitude.

9. An internal rotor motor, characterized in that, The segmented skew-pole motor rotor core structure described in any one of claims 1 to 8 is adopted.

10. An external rotor motor, characterized in that, The segmented skew-pole motor rotor core structure described in any one of claims 1 to 8 is adopted.

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