Low-harmonic permanent magnet motor rotor lamination and rotor structure

Abstract

The application discloses a low-harmonic permanent magnet motor rotor lamination and a rotor structure, which comprises a rotor lamination body, first V-shaped magnetic steel grooves and second V-shaped magnetic steel grooves are symmetrically arranged on each magnetic pole unit, the first V-shaped magnetic steel groove is located between an axle hole and the second V-shaped magnetic steel groove; first auxiliary grooves, second auxiliary grooves and third auxiliary grooves are arranged on the outer circle of the rotor, and the auxiliary grooves are symmetrically arranged on the unit magnetic pole with respect to the d-axis center line; the first auxiliary groove is located between the q-axis center line and the first V-shaped magnetic steel groove, the second auxiliary groove is located between the first V-shaped magnetic steel groove and the second V-shaped magnetic steel groove, and the third auxiliary groove is located between the second V-shaped magnetic steel groove and the d-axis center line. Three pairs of auxiliary grooves are arranged on the outer circle of the rotor, the double-V-shaped rotor topological structure and the shape and position of the rotor auxiliary grooves are reasonably designed, the distribution of the air gap magnetic field is optimized, the motor magnetic field harmonic is weakened, the motor tooth slot torque and torque ripple are reduced, and the vibration noise of the motor is improved.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a low-harmonic permanent magnet motor rotor lamination and rotor structure. Background Technology

[0002] Existing technology discloses a rotor lamination and a permanent magnet motor rotor. This solution proposes an example of an embedded double-V-shaped topology structure, which improves the vibration and noise of the motor through a preferred double-layer permanent magnet structure and rotor outer contour. Its structure is as follows: Figure 1 As shown.

[0003] This patent divides the outer contour line under each pole of the rotor into three segments. Using its optimized rotor outer contour line calculation formula, it designs the rotor's outer circumference, reducing the air gap magnetic field waveform distortion rate and effectively lowering the rotor's cogging torque and back EMF harmonic content, thus improving the overall NVH performance. However, this lamination outer contour line design significantly increases the motor's equivalent air gap, reducing the motor's output torque. Furthermore, the rotor structure primarily focuses on the motor's no-load performance and d-axis magnetic circuit design, neglecting the influence of the motor's armature reaction and q-axis magnetic circuit, resulting in still relatively high motor torque ripple, which has not been significantly improved. Summary of the Invention

[0004] To address the aforementioned deficiencies in existing technologies, a low-harmonic permanent magnet motor rotor lamination and rotor structure are provided. The magnetic field line distribution of the rotor magnetic circuit is optimized, reducing the impact of the motor armature reaction and improving the harmonic distortion of the motor's air gap magnetic field without affecting the motor's output torque.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, a low-harmonic permanent magnet motor rotor lamination includes a rotor lamination body, on which 2p magnetic pole units are provided, where p is the number of motor pole pairs; on each magnetic pole unit, a first V-shaped magnetic steel groove and a second V-shaped magnetic steel groove are symmetrically arranged about the d-axis, and the first V-shaped magnetic steel groove is located between the shaft hole and the second V-shaped magnetic steel groove. The feature is that a first auxiliary slot, a second auxiliary slot, and a third auxiliary slot are provided on the outer circumference of the rotor. Two of each type of auxiliary slot are provided on each unit magnetic pole, and the various auxiliary slots on the unit magnetic pole are symmetrically arranged about the center line of the d-axis. Among them, the first auxiliary slot is located between the center line of the q-axis and the first V-shaped magnet slot, the second auxiliary slot is located between the first V-shaped magnet slot and the second V-shaped magnet slot, and the third auxiliary slot is located between the second V-shaped magnet slot and the center line of the d-axis. Trapezoidal air slots are provided between the first V-shaped magnet slots, and the air slots are symmetrically arranged along the d-axis. The inner circle of the rotor includes two protruding keys, which are symmetrically arranged on the inner circle of the rotor.

[0006] According to the above technical solution, the three pairs of rotor auxiliary slots adopt an inverted triangular structure. Each auxiliary slot includes an outer edge line away from the d-axis and an inner edge line close to the d-axis. Chamfers are provided at the connection points between the inner edge line and the outer circle of the rotor, between the outer edge line and the outer circle of the rotor, and between the inner edge line and the outer edge. The line connecting the deepest point of the auxiliary slot and the center of the outer circle of the rotor is used as the center line of the auxiliary slot.

[0007] According to the above technical solution, the angle θ1 between the centerline of the first auxiliary groove and the centerline of the d-axis satisfies... The angle θ2 between the center line and the outer edge of the first auxiliary groove and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ3 between the centerline and inner edge of the first auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies ; The angle θ4 between the centerline of the second auxiliary groove and the centerline of the d-axis satisfies the following condition. The angle θ5 between the center line and the outer edge of the second auxiliary groove and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ6 between the centerline and inner edge of the second auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies ; The angle θ7 between the centerline of the third auxiliary groove and the centerline of the d-axis satisfies the following condition. The angle θ8 between the center line and the outer edge of the third auxiliary slot and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ9 between the centerline and inner edge of the third auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies .

[0008] According to the above technical solution, the outer diameter of the rotor lamination is 120mm~123mm, and p is taken as 4; The distance from the deepest part of the rotor auxiliary groove to the outer circle of the rotor is the depth of the rotor auxiliary groove. The depth w1 of the first auxiliary groove satisfies 0.6mm≤w1≤0.8mm, the depth w2 of the second auxiliary groove satisfies 0.5mm≤w2≤0.7mm, and the depth w3 of the third auxiliary groove satisfies 0.4mm≤w3≤0.6mm.

[0009] According to the above technical solution, the included angle α1 between the first V-shaped magnet grooves satisfies The polar arc angle α2 between the extensions of the inner edges of the two magnet slots near the d-axis and the outer circle of the rotor, respectively, and the lines connecting them to the center of the first V-shaped magnet slot, satisfies the following conditions: The distance H1 between the outer extension line of the first V-shaped magnet slot and the outer circle of the rotor gradually increases from the d-axis along the q-axis. The included angle α3 between the second V-shaped magnet grooves satisfies The polar arc angle α4 between the extensions of the inner edges of the two magnet slots near the d-axis and the outer circle of the rotor, respectively, and the lines connecting them to the center of the circle, satisfies the following conditions: The distance H4 between the outer extension line of the second V-shaped magnet slot and the outer circle of the rotor gradually increases from the d-axis along the q-axis; the lower side of the second V-shaped magnet slot is parallel to the d-axis.

[0010] According to the above technical solution, a trapezoidal air groove is provided between the first V-shaped magnet grooves. The air grooves are symmetrically arranged along the d-axis. The air grooves include parallel upper and lower side lines, as well as side lines connecting the upper and lower side lines. The side lines of the air grooves are parallel to the lower side of the magnet grooves and form a middle magnetic bridge. The center lines of the two middle magnetic bridges and the bottom extension lines of the two magnet grooves intersect at a point, and the lower side line is located on the line connecting the two intersection points. The upper side line is obtained by radially shifting the line connecting the two closest points of the magnets outward by H2, where H2 satisfies 0.5mm≤H2≤0.8mm.

[0011] According to the above technical solution, it also includes weight reduction holes and rivet holes. The 2p weight reduction holes are evenly distributed along the circumference between the magnet slot and the inner circle of the rotor; the center of the rivet holes is located on the q-axis.

[0012] According to the above technical solution, the inner circle of the rotor includes two convex keys, which are symmetrically arranged on the inner circle of the rotor. Based on the angle between the center line of the convex key and the d-axis, the convex keys are provided in various specifications. The angle between the symmetrical center line of the convex key and the d-axis of the rotor lamination satisfies... , N is the number of rotor segments, and n is an integer.

[0013] Secondly, a rotor structure is characterized by: employing the low-harmonic permanent magnet motor rotor laminations as described above, with V-shaped skewed poles along the axial direction on the rotor core section; on the rotor core section, the rotor skewed poles are symmetrically spaced along the axial direction in the middle, the skewed pole angle intervals between adjacent rotor laminations on one side of the core section are the same, and the maximum skewed pole angle of the rotor core section is... satisfy Where Q is the number of motor slots and N is the number of rotor segments.

[0014] Thirdly, a permanent magnet motor employs the rotor structure described above.

[0015] The present invention has the following beneficial effects: 1. The first auxiliary slot is located between the q-axis centerline and the first V-shaped magnet slot. It increases the q-axis magnetic reluctance, weakens the q-axis armature reaction of the motor, and reduces the torque ripple of the motor. The second auxiliary slot is located between the first and second V-shaped magnet slots. It can adjust the distribution of the air gap magnetic field of the motor and reduce the harmonic content in the air gap magnetic field. The third auxiliary slot is located between the second V-shaped magnet slot and the d-axis centerline. It increases the d-axis magnetic reluctance, improves the demagnetization resistance of the rotor permanent magnet, and weakens the cogging effect of the motor, thus reducing the cogging torque of the motor.

[0016] 2. The shape of the three pairs of auxiliary slots and their position relative to the double V-shaped rotor structure improve the distribution of the air gap magnetic field in the motor, effectively increase the sinusoidality of the air gap magnetic field, reduce the harmonic content, reduce the torque pulsation and electromagnetic force of the motor, and improve the vibration and noise performance of the motor. Furthermore, since the d-axis and q-axis inductance of the motor are reduced at the same time, the auxiliary slots have a smaller impact on the salient pole ratio of the motor, ensuring the peak torque and peak power performance of the motor output.

[0017] 3. The position and size of the auxiliary slot are defined by using the angle between the center line of the auxiliary slot and the center line of the d-axis, the angle between the center line of the auxiliary slot and the line connecting the other end of the outer edge to the center of the outer circle of the rotor, and the angle between the center line of the auxiliary slot and the line connecting the other end of the inner edge to the center of the outer circle of the rotor. This method is universally applicable to all outer diameter motor rotors.

[0018] 4. The distance H1 between the outer extension line of the first V-shaped magnet slot and the outer circle of the rotor gradually increases from the d axis along the q axis, and the distance H4 between the outer extension line of the second V-shaped magnet slot and the outer circle of the rotor gradually increases from the d axis along the q axis. This reduces the leakage of permanent magnets while satisfying the mechanical strength of the rotor.

[0019] 5. The trapezoidal air slot and the first V-shaped magnet slot approximately form a U-shaped topology. Compared with the traditional V-shaped magnetic pole structure, it reduces the saturation of the motor's q-axis magnetic circuit, increases the motor's q-axis inductance and salient pole ratio, reduces the motor's back EMF, improves the motor's output torque and peak power, reduces the amount of motor magnets used, and lowers the motor cost. At the same time, the trapezoidal air slot reduces the rotor weight and divides the middle magnetic bridge of the large V-shaped magnet slot in two, improving the mechanical strength of the rotor laminations.

[0020] 6. By using the rotor axial V-shaped skewed poles, the tooth harmonics of the motor are further reduced, the axial force of the motor is reduced, and the NVH performance of the motor is improved.

[0021] 7. Setting 2p weight reduction holes can reduce rotor weight, shorten the response time of motor acceleration and deceleration, and improve the power density and torque density of motor.

[0022] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0024] Figure 1 This is a schematic diagram of the existing structure; Figure 2 This is a schematic diagram of the structure of an embodiment provided by the present invention; Figure 3 This is a partial schematic diagram of an embodiment provided by the present invention; Figure 4 These are detailed diagrams of three auxiliary grooves provided in the embodiments of the present invention; Figure 5 This is a detailed view of the first V-shaped magnet groove provided in an embodiment of the present invention; Figure 6 This is a detailed view of the second V-shaped magnet groove provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the rotor inner circular keyway according to an embodiment of the present invention; Figure 8 This is a radial effect diagram of the rotor segmented skew poles according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the rotor axial V-shaped skew pole effect provided by the present invention; Figure 10 This is a comparison of the torque performance of the embodiments of the present invention with other solutions; Figure 11 This is a comparison of the radial electromagnetic force amplitude of the embodiments of the present invention and other solutions; In the figure, 1 is the rotor lamination body; 2 is the first V-shaped magnet slot; 3 is the second V-shaped magnet slot; 4 is the first auxiliary slot; 5 is the second auxiliary slot; 6 is the third auxiliary slot; 7 is the trapezoidal air slot; 8 is the weight reduction hole; 9 is the rivet hole; 10 is the protruding key; 11 is the magnet; and 12 is the shaft hole. Detailed Implementation

[0025] The following is in conjunction with the appendix Figures 2-11The principles and features of the present invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0026] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] Reference Figures 2-11 As shown, the present invention provides a low harmonic permanent magnet motor rotor lamination.

[0029] Example 1 It includes a rotor lamination body 1, on which 2p magnetic pole units are provided, where p is the number of motor pole pairs; on each magnetic pole unit, a first V-shaped magnetic steel groove 2 and a second V-shaped magnetic steel groove 3 are symmetrically arranged about the d-axis, and the first V-shaped magnetic steel groove is located between the shaft hole 12 and the second V-shaped magnetic steel groove.

[0030] The rotor outer circumference is provided with a first auxiliary slot 4, a second auxiliary slot 5, and a third auxiliary slot 6. Two of each type of auxiliary slot are provided on each unit magnetic pole. The various auxiliary slots on the unit magnetic pole are symmetrically arranged about the d-axis centerline. The first auxiliary slot is located between the q-axis centerline and the first V-shaped magnet slot, the second auxiliary slot is located between the first V-shaped magnet slot and the second V-shaped magnet slot, and the third auxiliary slot is located between the second V-shaped magnet slot and the d-axis centerline. Trapezoidal air slots 7 are provided between the first V-shaped magnet slots, and the air slots are symmetrically arranged along the d-axis. The inner circle of the rotor includes two protruding keys 10, which are symmetrically arranged on the inner circle of the rotor.

[0031] The first auxiliary slot, located between the q-axis centerline and the first V-shaped magnet slot, increases the q-axis magnetic reluctance, weakens the q-axis armature reaction, and reduces torque ripple. The second auxiliary slot, located between the first and second V-shaped magnet slots, adjusts the air gap magnetic field distribution, reducing harmonic content. The third auxiliary slot, located between the second V-shaped magnet slot and the d-axis centerline, increases the d-axis magnetic reluctance, improves the demagnetization resistance of the rotor permanent magnets, and weakens the cogging effect, reducing cogging torque.

[0032] In Embodiment 1, a preferred structural form of the auxiliary slot is given. The three pairs of rotor auxiliary slots adopt an inverted triangular structure. Each auxiliary slot includes an outer edge line away from the d-axis and an inner edge line close to the d-axis. Chamfers are provided at the connection points between the inner edge line and the outer circle of the rotor, between the outer edge line and the outer circle of the rotor, and between the inner edge line and the outer edge line. The line connecting the deepest point of the auxiliary slot and the center of the outer circle of the rotor is used as the center line of the auxiliary slot.

[0033] The shape of the three pairs of auxiliary slots and their position relative to the double V-shaped rotor structure improve the distribution of the air gap magnetic field in the motor, effectively increase the sinusoidality of the air gap magnetic field, reduce the harmonic content, reduce the motor's torque pulsation and electromagnetic force, and improve the motor's vibration and noise performance. Furthermore, since the motor's d-axis and q-axis inductance are reduced at the same time, the auxiliary slots have a smaller impact on the motor's salient pole ratio, ensuring the peak torque and peak power performance of the motor output.

[0034] Preferably, the specific design dimensions of the auxiliary groove are given.

[0035] like Figures 3-4 As shown, the angle θ1 between the centerline of the first auxiliary groove and the centerline of the d-axis satisfies The angle θ2 between the center line and the outer edge of the first auxiliary groove and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ3 between the centerline and inner edge of the first auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies ; The angle θ4 between the centerline of the second auxiliary groove and the centerline of the d-axis satisfies the following condition. The angle θ5 between the center line and the outer edge of the second auxiliary groove and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ6 between the centerline and inner edge of the second auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies ; The angle θ7 between the centerline of the third auxiliary groove and the centerline of the d-axis satisfies the following condition. The angle θ8 between the center line and the outer edge of the third auxiliary slot and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ9 between the centerline and inner edge of the third auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies .

[0036] In the above preferred embodiments, the position and size of the auxiliary slot are defined by using the various included angles described above, which is universally applicable to all outer diameter motor rotors. In some embodiments, the outer diameter of the rotor lamination is 120mm~123mm, and p is 4. Then, the width of the center line of the first auxiliary slot and the center line of the d-axis on the outer circumference of the rotor satisfies 21.7mm~24.2mm, the width of the line connecting the other end of the center line and the outer edge of the first auxiliary slot to the center of the outer circle of the rotor on the outer circumference satisfies 0.7mm~1.4mm, and the width of the line connecting the other end of the center line and the inner edge of the first auxiliary slot to the center of the outer circle of the rotor on the outer circumference satisfies 0.7mm~1.4mm.

[0037] The width of the center line of the second auxiliary groove and the center line of the d-axis on the outer circumference of the rotor is 13.2mm~15.0mm. The width of the line connecting the other end of the center line and outer edge of the second auxiliary groove to the center of the outer circle of the rotor on the outer circumference is 2.8mm~3.9mm. The width of the line connecting the other end of the center line and inner edge of the second auxiliary groove to the center of the outer circle of the rotor on the outer circumference is 0.7mm~1.4mm.

[0038] The width of the center line of the third auxiliary groove and the center line of the d-axis on the outer circumference of the rotor is 6.6mm~8.2mm. The width of the line connecting the other end of the center line and outer edge of the third auxiliary groove to the center of the outer circle of the rotor on the outer circumference is 1.4mm~2.4mm. The width of the line connecting the other end of the center line and inner edge of the third auxiliary groove to the center of the outer circle of the rotor on the outer circumference is 1.4mm~2.4mm.

[0039] The distance from the deepest part of the rotor auxiliary groove to the outer circle of the rotor is the depth of the rotor auxiliary groove. The depth w1 of the first auxiliary groove satisfies 0.6mm≤w1≤0.8mm, the depth w2 of the second auxiliary groove satisfies 0.5mm≤w2≤0.7mm, and the depth w3 of the third auxiliary groove satisfies 0.4mm≤w3≤0.6mm.

[0040] Example 2 The structure and principle of Embodiment 2 are similar to those of Embodiment 1, except that a preferred structural form of the magnetic steel groove is provided based on Embodiment 1. However, the structure of the present invention is not limited to the following structural dimensions.

[0041] like Figure 3 , 5 As shown in Figure 6, the included angle α1 between the first V-shaped magnet slots satisfies The polar arc angle α2 between the extensions of the inner edges of the two magnet slots near the d-axis and the outer circle of the rotor, respectively, and the lines connecting them to the center of the first V-shaped magnet slot, satisfies the following conditions: The distance H1 between the outer extension line of the first V-shaped magnet slot and the outer circle of the rotor gradually increases from the d axis along the q axis, which reduces the leakage flux of the permanent magnet while satisfying the mechanical strength of the rotor. The included angle α3 between the second V-shaped magnet grooves satisfies The pole arc angle α4 between the extensions of the inner edges of the two magnet slots 11 placed in the second V-shaped magnet slots near the d-axis and the intersection points of the rotor outer circle and the line connecting the center of the circle satisfies the following conditions: The distance H4 between the outer extension line of the second V-shaped magnet slot and the outer circle of the rotor gradually increases from the d-axis along the q-axis direction, which reduces the leakage flux of the permanent magnet while satisfying the mechanical strength of the rotor; the lower side of the second V-shaped magnet slot is parallel to the d-axis.

[0042] Example 3 The structure and principle of Example 3 are similar to those of Example 2, except that the trapezoidal air slot and the first V-shaped magnet slot approximately form a U-shaped topology. Compared with the traditional V-shaped magnetic pole structure, this reduces the saturation of the motor's q-axis magnetic circuit, increases the motor's q-axis inductance and salient pole ratio, reduces the motor's back EMF, improves the motor's output torque and peak power, reduces the amount of motor magnets used, and lowers the motor cost. At the same time, the trapezoidal air slot reduces the rotor weight and divides the middle magnetic bridge of the large V-shaped magnet slot in two, improving the mechanical strength of the rotor laminations.

[0043] Trapezoidal air slots are provided between the first V-shaped magnet slots. The air slots are symmetrically arranged along the d-axis. Each air slot includes a parallel upper and lower side line, as well as a side line connecting the upper and lower side lines. The side line of the air slot is parallel to the lower side of the magnet slot and forms a middle magnetic bridge. The center line of the middle magnetic bridge on both sides and the extension line of the bottom of the magnet slot on both sides intersect at a point. The lower side line is located on the line connecting the two intersection points. The line connecting the two closest points of the magnets is translated radially outward by H2 to obtain the upper side line. H2 satisfies 0.5mm≤H2≤~0.8mm.

[0044] In embodiments 1-3, weight-reducing holes 8 and rivet holes 9 are also included. 2p weight-reducing holes are evenly distributed along the circumference between the magnet slots and the inner circle of the rotor; the center of the rivet holes is located on the q-axis. The rivet holes are used for rotor lamination stacking, and the weight-reducing holes are used to reduce the rotor's moment of inertia.

[0045] Example 4 The structure and principle of Example 4 are similar to those of Examples 1-3, except that: Figures 7-9 As shown, based on the angle between the center line of the convex key and the d-axis, the convex key is configured in various specifications. The angle between the symmetrical center line of the convex key and the d-axis of the rotor lamination satisfies... , N is the number of rotor segments, and n is an integer.

[0046] The rotor's inner circle is equipped with a key that matches the slots on the shaft. The placement of this key allows for segmented skewed pole configuration along the rotor's axial direction. As shown in the figure, rotor skew effectively reduces tooth harmonic components in the motor's magnetic field, suppressing vibration and noise. The angle β between the key's centerline and the d-axis is the skew angle for that segment of the rotor; the value of β varies for different rotor core segments. The figure shows the effect of three skewed pole configurations, with skew angles of β, 0, and -β, respectively. As shown, the rotor employs a V-shaped skew configuration along the axial direction, with symmetrical skew angles along the middle. The difference in skew angle between adjacent core segments on each side is the same, reducing axial force and improving the motor's NVH performance.

[0047] The present invention also provides a rotor structure.

[0048] The low-harmonic permanent magnet motor rotor laminations described above employ a V-shaped skewed pole configuration along the axial direction on the rotor core section. On the rotor core section, the skewed poles are symmetrically spaced along the axial direction, with adjacent laminations on each side having the same skewed pole angle interval. The maximum skewed pole angle of the rotor core section is... satisfy Where Q is the number of motor slots and N is the number of rotor segments.

[0049] by Figure 9 For example, its sloping polar angles are -β, 0, β, β, 0, -β.

[0050] The present invention also provides a motor, such as Figures 7-9 As shown, it includes the rotor structure described above.

[0051] Taking an 8-pole, 48-slot motor as an example, the rotor has 4 pole pairs (p) and 6 axial segments (N). The included angle α1 of the first V-shaped magnet is in the range of 76.5° to 85.5°, the included angle α2 of the pole arc of the first V-shaped magnet slot is in the range of 30.15° to 32.4°, the included angle α3 of the second V-shaped magnet is in the range of 99° to 135°, and the included angle α4 of the second pole arc of the second V-shaped magnet slot is in the range of 17.1° to 18.9°. The rotor is distributed axially as follows... Figure 9 The 6-segment skew configuration shown has β in the range of 2.25° to 2.75°.

[0052] Eight rotor poles are distributed along the outer circumference of the rotor. Each rotor pole has three pairs of auxiliary slots, which are symmetrical about the d-axis. Auxiliary slot 1 is located between the first V-shaped magnet slot and the q-axis, with its central angle θ1 ranging from 20.7° to 22.5°, and its outer side angles θ2 and θ3 both ranging from 0.675° to 1.35°. Auxiliary slot 2 is located between the first and second V-shaped magnet slots, with its central angle θ4 ranging from 12.6° to 14.4°, its outer side angle θ5 ranging from 2.7° to 3.6°, and its inner side angle θ6 ranging from 0.675° to 1.35°. Auxiliary slot 3 is located between the second V-shaped magnet slot and the d-axis, with its central angle θ7 ranging from 6.3° to 7.65°, and its outer side angles θ8 and θ9 both ranging from 1.35° to 2.25°.

[0053] As shown in Table 1, the double V-shaped rotor structure described in Examples 2-4 can achieve lower motor torque ripple. Traditional designs often only have auxiliary slots on the rotor d-axis, which can effectively reduce motor torque ripple, but have little effect on weakening the radial and tangential electromagnetic forces of the motor. However, by further adopting the three-pair rotor auxiliary slot structure described in Example 1, under the same current excitation, the peak output torque of the motor remains basically unchanged, while the torque ripple is further reduced. The amplitudes of the main order radial and tangential electromagnetic forces of the motor are also effectively attenuated, which can greatly improve the NVH performance of the motor.

[0054] Table 1

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A low harmonic permanent magnet motor rotor lamination, comprising a rotor lamination body, wherein the rotor lamination body is provided with 2p magnetic pole units, where p is the number of motor pole pairs; and a first V-shaped magnetic steel groove and a second V-shaped magnetic steel groove are symmetrically arranged about the d-axis on each magnetic pole unit, wherein the first V-shaped magnetic steel groove is located between the shaft hole and the second V-shaped magnetic steel groove. Its features are: The rotor has a first auxiliary slot, a second auxiliary slot, and a third auxiliary slot on its outer circumference. Two of each type of auxiliary slot are provided on each unit magnetic pole. The various auxiliary slots on the unit magnetic pole are symmetrically arranged about the d-axis centerline. The first auxiliary slot is located between the q-axis centerline and the first V-shaped magnet slot, the second auxiliary slot is located between the first V-shaped magnet slot and the second V-shaped magnet slot, and the third auxiliary slot is located between the second V-shaped magnet slot and the d-axis centerline. Trapezoidal air slots are provided between the first V-shaped magnet slots, and the air slots are symmetrically arranged along the d-axis. The inner circle of the rotor includes two protruding keys, which are symmetrically arranged on the inner circle of the rotor. The three pairs of rotor auxiliary slots adopt an inverted triangular structure. Each auxiliary slot includes an outer edge line away from the d-axis and an inner edge line close to the d-axis. Chamfers are provided at the connection points between the inner edge line and the outer circle of the rotor, between the outer edge line and the outer circle of the rotor, and between the inner edge line and the outer edge line. The line connecting the deepest part of the auxiliary slot with the center of the outer circle of the rotor is used as the center line of the auxiliary slot. The angle θ1 between the centerline of the first auxiliary groove and the centerline of the d-axis satisfies the following condition. The angle θ2 between the center line and the outer edge of the first auxiliary groove and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ3 between the centerline and inner edge of the first auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies ; The angle θ4 between the centerline of the second auxiliary groove and the centerline of the d-axis satisfies the following condition. The angle θ5 between the center line and the outer edge of the second auxiliary groove and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ6 between the centerline and inner edge of the second auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies ; The angle θ7 between the centerline of the third auxiliary groove and the centerline of the d-axis satisfies the following condition. The angle θ8 between the center line and the outer edge of the third auxiliary slot and the line connecting the other end of the outer edge to the center of the rotor's outer circle satisfies The angle θ9 between the centerline and inner edge of the third auxiliary groove and the line connecting the other end of the inner edge to the center of the outer circle of the rotor satisfies .

2. The low harmonic permanent magnet motor rotor lamination according to claim 1, characterized in that: The outer diameter of the rotor lamination is 120mm~123mm, and p is 4; The distance from the deepest part of the rotor auxiliary groove to the outer circle of the rotor is the depth of the rotor auxiliary groove. The depth w1 of the first auxiliary groove satisfies 0.6mm≤w1≤0.8mm, the depth w2 of the second auxiliary groove satisfies 0.5mm≤w2≤0.7mm, and the depth w3 of the third auxiliary groove satisfies 0.4mm≤w3≤0.6mm.

3. The low harmonic permanent magnet motor rotor lamination according to claim 1, characterized in that: The included angle α1 between the first V-shaped magnet grooves satisfies The polar arc angle α2 between the extensions of the inner edges of the two magnet slots near the d-axis and the outer circle of the rotor, respectively, and the lines connecting them to the center of the first V-shaped magnet slot, satisfies the following conditions: The distance H1 between the extended line of the outer side of the first V-shaped magnet slot and the outer circle of the rotor gradually increases from the d-axis to the q-axis. The included angle α3 between the second V-shaped magnet grooves satisfies The polar arc angle α4 between the extensions of the inner edges of the two magnet slots near the d-axis and the outer circle of the rotor, respectively, and the lines connecting them to the center of the circle, satisfies the following conditions: The distance H4 between the outer extension line of the second V-shaped magnet slot and the outer circle of the rotor gradually increases from the d-axis to the q-axis; the lower side of the second V-shaped magnet slot is parallel to the d-axis.

4. The low harmonic permanent magnet motor rotor lamination according to claim 3, characterized in that: The air trough includes a parallel upper and lower edge line, and a side line connecting the upper and lower edge lines; the side line of the air trough is parallel to the lower side of the magnet trough and forms a middle magnetic bridge; the center line of the middle magnetic bridge on both sides and the extension line of the bottom of the magnet trough on both sides intersect at a point, and the lower edge line is located on the line connecting the two intersection points; the line connecting the two closest points of the magnets is translated radially outward by H2 to obtain the upper edge line, where H2 satisfies 0.5mm≤H2≤0.8mm.

5. The low harmonic permanent magnet motor rotor lamination according to claim 1, characterized in that: It also includes weight reduction holes and rivet holes. The 2p weight reduction holes are evenly distributed along the circumference between the magnet slot and the inner circle of the rotor; the center of the rivet holes is located on the q-axis.

6. The low harmonic permanent magnet motor rotor lamination according to any one of claims 1-5, characterized in that: Based on the angle between the centerline of the convex key and the d-axis, the convex key is available in various specifications. The angle between the symmetrical centerline of the convex key and the d-axis of the rotor lamination satisfies... , N is the number of rotor segments, and n is an integer.

7. A rotor structure, characterized in that: The low-harmonic permanent magnet motor rotor laminations as described in claim 6 employ a V-shaped skewed pole configuration along the axial direction on the rotor core section. On the rotor core section, the rotor skewed poles are symmetrically positioned along the axial direction, and the skewed pole angle interval between adjacent rotor laminations on one side of the core section is the same. The maximum skewed pole angle 2nβ of the rotor core section satisfies... Where Q is the number of motor slots and N is the number of rotor segments.

8. A permanent magnet motor, characterized in that: The rotor structure described in claim 7 is adopted.

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