Motor rotor, method for determining skewed pole angle of motor rotor and motor

Abstract

The invention relates to a motor rotor, a method for determining the skewed pole angle of the motor rotor and a motor, the motor rotor comprises N skewed pole units, the N skewed pole units comprise a first skewed pole unit,..., an (N-1) th skewed pole unit and an Nth skewed pole unit which are sequentially arranged along the axial direction of the motor rotor, N is an integer greater than or equal to 3, and N is an integer greater than or equal to 1. The skewed pole angle between the first skewed pole unit and the second skewed pole unit is alpha 1, the skewed pole angle between the (N-1) th skewed pole unit and the Nth skewed pole unit is alpha (N-1), the total skewed pole angle of the multiple sections of skewed pole units is A, A > = alpha 1 / 2 + alpha 1 +... + alpha (N-1) + alpha (N-1) / 2, 0 < = alpha 1 < = 2 * A / N,..., 0 < = alpha (N-1) < = 2 * A / N, and at least alpha i is not equal to alpha (N-i), i is a positive integer smaller than or equal to N-1. According to the invention, the NVH of the motor can be maximally reduced.

Description

Technical Field

[0001] The present invention relates to the field of motors, and particularly to a motor rotor, a method for determining the skew angle of a motor rotor, and a motor. Background Art

[0002] In recent years, the new energy vehicle industry has developed rapidly. As a core component of new energy vehicles, the motor provides power output for new energy vehicles and greatly affects the performance of new energy vehicles. Therefore, the requirements for motors in the new energy vehicle market are getting higher and higher. NVH is an important standard for motor performance. The skew motor can reduce the distortion rate of no-load back electromotive force, load torque ripple, and load electromagnetic radial force wave by changing the skew angle between different segments of the rotor core. Further, the NVH of the motor can be reduced.

[0003] In the prior art, there are skew methods in the forms of "one" character and "V" character. The skew angles between multiple skew pole units follow certain rules, and the magnitudes of each skew angle are fixed or multiple skew angles are symmetrically arranged. Limited by the rule that each skew angle is the same, the effect of reducing the NVH of the motor is not significant. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0005] According to a first aspect of an embodiment of the present application, a motor rotor is provided, including N skew pole units. The N skew pole units include a first skew pole unit, a... (N - 1)th skew pole unit, and an Nth skew pole unit arranged in sequence along the axial direction of the motor rotor. Wherein, N is an integer greater than or equal to 3. The skew angle between the first skew pole unit and the second skew pole unit is α1, and the skew angle between the (N - 1)th skew pole unit and the Nth skew pole unit is α (N-1) , the total skew angle of multiple skew pole units is A, where A≥α1 / 2 + α1 +... + α (N-1) +α (N-1) / 2, 0≤α1≤2*A / N,..., 0≤α (N-1) ≤2*A / N, and at least there exists α i ≠α (N-i) , where i is a positive integer less than or equal to N - 1.

[0006] In some embodiments, each segment of the skewed pole unit has the same number of multiple magnetic poles evenly distributed circumferentially along the motor rotor. Each magnetic pole includes two pairs of magnet slots arranged in pairs and permanent magnets disposed in the magnet slots. The magnet slots penetrate both end faces of the core lamination stack along the axial direction of the motor rotor. Each pair of magnet slots arranged in pairs is inclined toward opposite sides in the circumferential direction of the motor rotor with respect to the radial direction of the motor rotor, so as to be configured such that the distance from the magnet slots to the axis of the motor rotor in the circumferential direction forms a V shape that gradually expands toward the radially outer side.

[0007] In some embodiments, magnetic isolation slots are provided on both sides of the magnet slots. The magnetic isolation slots penetrate the end face of the skewed pole unit along the axial direction of the motor rotor. The provision of the magnetic isolation slots reduces magnetic leakage.

[0008] In some embodiments, the motor rotor further includes a rotor shaft. The core lamination stack is hollow and sleeved on the rotor shaft. Key grooves are axially formed on the outer peripheral surface of the rotor shaft. Positioning keys connected to the key grooves are provided on the inner peripheral surface of the core lamination stack connected to the rotor shaft. The skewed pole angle is controlled at different circumferential positions on the inner peripheral surface of the core lamination stack by using the positioning keys, which is convenient, reliable, and easy to implement.

[0009] In some embodiments, auxiliary grooves recessed radially toward the axis of the core lamination stack are provided on the outer peripheral surface of the core lamination stack. The auxiliary grooves extend along the axial direction of the motor rotor and correspond to one end of the magnet slots far from the axis of the motor rotor. The provision of the auxiliary grooves can reduce the radial force and lower the noise.

[0010] In some embodiments, N≤7. If the number of segments of the skewed pole unit is too high, the manufacturing difficulty increases, and generally 7 segments of skewed poles can meet the motor performance requirements.

[0011] In some embodiments, the length of the skewed pole unit in the axial direction of the motor rotor is 10 - 20 mm. Being too long or too short will increase the process complexity.

[0012] In some embodiments, the skewed pole unit includes six magnetic poles.

[0013] According to the second aspect of the embodiments of the present application, a method for determining the skewed pole angle of a motor rotor is provided, which is used to determine the skewed pole angle of the motor rotor as described in any one of the embodiments in the first aspect. The motor rotor includes N segments of skewed pole units. The N segments of skewed pole units include a first skewed pole unit, ..., a (N - 1)th skewed pole unit, and an Nth skewed pole unit arranged in sequence along the axial direction of the motor rotor. Wherein, N is an integer greater than or equal to 3. The skewed pole angle between the first skewed pole unit and the second skewed pole unit is α1, and the skewed pole angle between the (N - 1)th skewed pole unit and the Nth skewed pole unit is α(N-1) For a multi-segment skewed pole unit with a total skewed pole angle of A, a motor stator with a number of winding slots B for use in conjunction with a motor rotor, and a total axial length C of the multi-segment skewed pole unit along the axial direction of the motor rotor, the method comprises the following steps:

[0014] S1: Determine the range of the total skewed pole angle A based on the number of winding slots B of the motor stator. The calculation formula is A ≤ 360 / B. Determine the range of the number of segments N of the rotor core based on the height C of the rotor core. The calculation formula is: N = C / 18 (3 ≤ N ≤ 7, rounded to the nearest integer). Define the range of the skewed pole angle between any adjacent skewed pole units based on the total skewed pole angle A and the number of core segments N between the multi-segment skewed pole units. Among them, A ≥ α1 / 2 + α1 +... + α (N-1) +α (N-1) / 2, 0 ≤ α1 ≤ 2*A / N,..., 0 ≤ α (N-1) ≤ 2*A / N;

[0015] S2: Select the total skewed pole angle A within the range of the total skewed pole angle determined in S1, select the number of segments N within the range of the skewed pole unit segments determined in S1, preset each skewed pole angle, then establish a motor rotor model and calculate the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force;

[0016] S3: Load the established model into simulation software;

[0017] S4: In the output options of the parameterization interface of the simulation software, select the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force and set them as optimization objectives, and set each skewed pole angle as a scanning parameter;

[0018] S5: Run the simulation software to verify the calculated no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force;

[0019] S6: If the verification is not completed, return to S5 and check whether there is interference in the motor rotor model and whether the set skewed pole angle is correct; if the verification is completed, set the sensitivity analysis conditions. After the sensitivity analysis conditions are set, perform a scanning operation to obtain different combinations of skewed pole angle values;

[0020] S7: Obtain a calculation model of the skewed pole angle to the optimization objective based on the obtained combination of skewed pole angles, judge the accuracy of the model. If the accuracy is greater than 90%, proceed to step S8. If the accuracy is less than 90%, return to step S6 and re-select the angle range.

[0021] S8: Select the optimal combination of skewed pole angles.

[0022] By performing parametric simulation on each skewed pole angle, within the range of the skewed pole angle defined in step S1, finally determine α1,..., α(N-1) 。

[0023] In some embodiments, in S6, the setting of the sensitivity analysis conditions includes:

[0024] S61. Adding the range of each skew pole angle obtained in S1 as the scanning range of the skew pole angle;

[0025] S62. Adding the optimization target values of the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force;

[0026] S63. Selecting the Latin hypercube algorithm.

[0027] In some embodiments, after S7 and before S8, it further includes:

[0028] Further narrowing the skew pole angle range within the range of S61 and setting the optimization target, and performing a scanning operation.

[0029] According to the third aspect of the embodiments of the present application, there is provided a motor, including the motor rotor described in any one of the embodiments in the first aspect, or the method for determining the skew pole angle of the motor rotor described in any one of the embodiments in the second aspect.

[0030] The additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Other features and advantages of the present invention are described below, which more specifically explains the present invention based on the embodiments in conjunction with the drawings.

[0032] Figure 1 is a schematic structural diagram of a motor rotor according to an embodiment of the present invention;

[0033] Figure 2 is a schematic structural diagram of a skew pole unit of a motor rotor according to an embodiment of the present invention;

[0034] Figure 3 is a schematic diagram of the skew pole angle between the rotor of the first skew pole unit and the second skew pole unit. The dashed part in the figure is the rotor punching group of the second skew pole unit;

[0035] Figure 4 is a schematic diagram of the skew pole angle between the second skew pole unit and the third skew pole unit. The dashed part in the figure is the rotor punching group of the second skew pole unit;

[0036] Figure 5 is a schematic diagram of the skew pole angle between the third skew pole unit and the fourth skew pole unit. The dashed part in the figure is the rotor punching group of the fourth skew pole unit;

[0037] Figure 6 is the magnetic force distribution diagram of a single skewed pole unit;

[0038] Figure 7 is the relationship between the frequency and the Fourier decomposition of the line back electromotive force of a skewed pole motor according to an embodiment of the present invention;

[0039] Figure 8 is the relationship between the frequency and the Fourier decomposition of the line back electromotive force of a non-skewed pole motor;

[0040] Figure 9 is the relationship between the frequency and the Fourier decomposition of the line back electromotive force of a one-word symmetric skewed pole motor;

[0041] Figure 10 is the relationship diagram between the space-frequency and the force density of a skewed pole motor according to an embodiment of the present invention;

[0042] Figure 11 is the relationship diagram between the space-frequency and the force density of a non-skewed pole motor;

[0043] Figure 12 is the relationship diagram between the space-frequency and the force density of a one-word symmetric skewed pole motor;

[0044] Figure 13 is the torque trend diagram of a skewed pole motor according to an embodiment of the present invention;

[0045] Figure 14 is the torque trend diagram of a non-skewed pole motor;

[0046] Figure 15 is the torque trend diagram of a one-word symmetric skewed pole motor.

[0047] Description of reference numerals:

[0048] Motor rotor - 100;

[0049] 10 - Skewed pole unit, 10a - First skewed pole unit, 10b - Second skewed pole unit, 10c - Third skewed pole unit, 10d - Fourth skewed pole unit, 11 - Rotor core punching set, 12 - Permanent magnet, 13 - Magnet steel slot, 14 - Magnetic isolation slot, 15 - Positioning key, 16 - Auxiliary slot; 20 - Rotor shaft, 21 - Keyway. Detailed implementation manners

[0050] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. It should be noted that the terms "upper", "lower", "left", "right", "front", "rear" and similar expressions used herein are for illustrative purposes only and are not limitations to the present invention.

[0051] The present invention provides a method for determining the skew angle of a motor rotor. The motor rotor includes N segments of skew pole units. The skew angle between the first skew pole unit and the second skew pole unit is α1, the skew angle between the second skew pole unit and the third skew pole unit is α2, and the skew angle between the (N - 1)th skew pole unit and the Nth skew pole unit is α (N-1) , each segment of skew pole unit has the same number of multiple magnetic poles evenly distributed along the circumferential direction of the motor rotor. The total skew angle of the multiple segments of skew pole units is A, the number of winding slots of the motor stator used in cooperation with the motor rotor is B, and the total axial length of the multiple segments of skew pole units along the motor rotor is C. It is characterized by including the following steps:

[0052] S1: Determine the range of the total skew angle A according to the number of winding slots B of the motor stator. The calculation formula is A ≤ 360 / B. Determine the range of the number of segments N of the rotor core according to the rotor core height C. The calculation formula is: N = C / 18 (3 ≤ N ≤ 7, rounded to the nearest integer). Limit the skew angle range between any adjacent skew pole units according to the total skew angle A between the multiple segments of skew pole units and the number of core segments N. Among them, A ≥ α1 / 2 + α1 + α2 +... α (N-1) + α (N-1) / 2, 0 ≤ α1 ≤ 2*A / N, 0 ≤ α2 ≤ 2*A / N,..., 0 ≤ α (N-1) ≤ 2*A / N; S2: Select the total skew angle A within the range of the total skew angle determined in step S1, select the number of segments N within the range of the number of skew pole unit segments determined in step S1. After presetting each skew angle, establish a motor rotor model in the ansoft maxwel software and calculate the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force; S3: Load the model established in ansoft maxwel into the OptiSLang simulation software; S4: In the output options of the parameterization interface of the OptiSLang simulation software, select the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force and set them as optimization objectives, and set each skew angle as a scanning parameter; S5: Run the OptiSLang simulation software to check the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force calculated by ansoftmaxwel; S6: If the check is not completed, return to step S5 and check whether there is interference in the motor rotor model and whether the skew setting angle is correct. After the check is completed, set the sensitivity analysis conditions: S61. Add the skew angle ranges obtained in step S1 as the scanning range of the skew angle; S62. Add the optimization target values of the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force; S63. Select the Latin hypercube algorithm. After the sensitivity analysis conditions are set, perform a scanning operation to obtain different skew angle values α1, α2,... and α (N-1)Combination; S7: Based on the skew pole angle combination obtained in step S6, derive a calculation model from the skew pole angle to the optimization target, and judge the accuracy of the model. If the accuracy is greater than 90%, proceed to step S8; if the accuracy is less than 90%, return to step S6 and reselect the angle range; S8: Further narrow the skew pole angle range within the range in S61 and set the optimization target; S9: Perform a scanning operation; S10: Select the optimal skew pole angle combination.

[0053] Using the method for determining the skew pole angle of a motor rotor provided by the present invention, with the aim of reducing the distortion rate of no-load back electromotive force, load torque ripple, and load electromagnetic radial force, scan combinations of multiple skew pole angles, and finally obtain the optimal solution. The irregular skew pole angles obtained after parameter simulation by the simulation software, compared with the regular skew pole angles in the prior art, can effectively reduce the motor NVH indicators (distortion rate of no-load back electromotive force, load torque ripple, and load electromagnetic radial force), improve the motor performance, and reduce the noise, vibration, and harshness exhibited by the motor during operation.

[0054] Ansoft maxwell (ansoft maxwell EM) is an electromagnetic software in industrial applications, an electromagnetic field analysis software. OptiSLang is a tool for parameter optimization, which can utilize the excellent algorithms of OptiSLang to make the optimization design process more rapid and convenient.

[0055] Another object of the present invention is to propose a motor rotor 100, the motor rotor includes N segments of skew pole units, the skew pole angle between the first skew pole unit and the second skew pole unit is α1, the skew pole angle between the second skew pole unit and the third skew pole unit is α2, and the skew pole angle between the (N - 1)th skew pole unit and the Nth skew pole unit is α (N-1) , each segment of skew pole unit has the same number of multiple magnetic poles evenly distributed along the circumferential direction of the motor rotor, and at least there is α i ≠α (N-i) , where i is a positive integer less than or equal to N - 1. For example, when N is 5, at least there is α1≠α4, or at least there is α2≠α3. Of course, it is also possible to have both α1≠α4 and α2≠α3 simultaneously. Each segment of skew pole unit has the same number of multiple magnetic poles evenly distributed along the circumferential direction of the motor rotor, and the total skew pole angle of multiple segments of skew pole units is A, where A≥α1 / 2 + α1 + α2 +...α (N-1) +α (N-1) / 2, 0≤α1≤2*A / N, 0≤α2≤2*A / N,..., 0≤α (N-1) ≤2*A / N.

[0056] The skew pole angle combination used in the motor rotor of the present application has the advantages of reducing the motor NVH indicators and improving the motor performance.

[0057] like Figure 1 and Figure 2 As shown, each magnetic pole of the oblique pole unit 10 includes two pairs of magnetic steel slots 13 arranged in pairs and permanent magnets 12 arranged in the magnetic steel slots 13. The magnetic steel slots penetrate the end faces of the core punching group 11 on both sides along the axial direction of the motor rotor. Each pair of magnetic steel slots 13 is inclined toward the opposite side of the circumferential direction of the motor rotor relative to the radial direction of the motor rotor, so that the distance between the magnetic steel slots and the axis of the motor rotor in the circumferential direction is gradually expanded toward the radial outside. Magnetic isolation grooves 14 are arranged on both sides of the magnetic steel slots. The magnetic isolation grooves 14 penetrate the end faces of the oblique pole unit 10 along the axial direction of the motor rotor. The provision of the magnetic isolation grooves 14 is beneficial to reducing magnetic leakage.

[0058] like Figure 1 As shown, the motor rotor also includes a rotor shaft 20, the core punching sheet group 11 is hollow and sleeved on the rotor shaft 20, a keyway 21 is axially provided on the outer circumference of the rotor shaft, a positioning key 15 connected to the keyway is provided on the inner circumference of the rotor core connected to the rotor shaft, a keyway is provided on the rotor shaft, and positioning keys at different angles on the oblique pole units are used to realize the misalignment and deflection of each oblique pole unit on the circumference of the motor rotor, which is convenient, reliable and easy to implement.

[0059] like Figures 1 to 5 As shown, in this embodiment, the motor rotor is divided into four sections of oblique pole units 10, and the structure of the core punching group in each oblique pole unit on the end faces on both sides is the same: it includes six groups of two pairs of V-shaped magnetic steel grooves 13, and the six groups of magnetic steel grooves are evenly distributed along the circumferential direction of the core punching group 11 and penetrate the core punching group. The paired magnetic steel grooves are distributed with the radius of the core punching group as the symmetrical center line. Adjacent oblique pole units are staggered at a certain angle along the circumferential direction of the motor rotor to achieve the oblique poles of different oblique pole units. The oblique pole angles of different oblique pole units are controlled by changing the circumferential position of the positioning key on the inner circumferential surface of the core punching group.

[0060] In some embodiments, the motor rotor includes N segments of bevel pole units, 3≤N≤7. Generally, 7 segments of bevel poles can meet the use requirements of new energy vehicle motors. When the bevel pole unit is greater than 7 segments, the manufacturing difficulty of the process will increase. When it is less than 3 segments, it is the same as the symmetrical bevel pole and the straight bevel pole, which does not conform to the design concept of irregular random combination and distribution of multiple bevel pole angles proposed in the present invention.

[0061] In some embodiments, the length of the oblique pole unit in the axial direction of the motor rotor is 10-20 mm. To facilitate the manufacture of the oblique pole unit, the length of the oblique pole unit in the direction of the motor rotor shaft is generally controlled between 10-20 mm. If it is less than 10 mm or greater than 20 mm, the difficulty of manufacture will increase.

[0062] As shown Figure 6 in the figure, a single skewed pole unit in this embodiment includes six magnetic poles. Each magnetic pole of the double-V motor is mainly generated by permanent magnets in two pairs of magnetic steel slots corresponding to it. The figure shows the distribution diagram of the magnetic force lines of the six magnetic poles. The six magnetic poles are evenly distributed along the circumferential direction of the iron core punching sheet group, and the included angle between adjacent magnetic poles is 60°. The six magnetic poles are respectively: the first magnetic pole, the second magnetic pole, the third magnetic pole,... the sixth magnetic pole. The motor rotor altogether includes 4 skewed pole units. The skewed pole units are columnar as a whole and are mainly formed by stacking a plurality of iron core punching sheets, which are respectively the first skewed pole unit, the second skewed pole unit, the third skewed pole unit, and the fourth skewed pole unit. The skewed pole angle between the first magnetic pole of the first skewed pole unit and the first magnetic pole of the second skewed pole unit is α1, the skewed pole angle between the first magnetic pole of the second skewed pole unit and the first magnetic pole of the third skewed pole unit is α2, and the skewed pole angle between the first magnetic pole of the third skewed pole unit and the first magnetic pole of the fourth skewed pole unit is α3. In this embodiment, α1, α2, and α3 are all different. Specifically: α1 = 1°, α2 = 2.3°, α3 = 1.66°.

[0063] An auxiliary groove 16 recessed towards the axis of the motor rotor is provided on the outer peripheral surface of the iron core punching sheet group. The auxiliary groove 16 extends along the axial direction of the motor rotor and corresponds to the end of the magnetic steel groove far from the axis of the motor rotor. The setting of the auxiliary groove can reduce the motor noise and reduce the radial force of the motor.

[0064] In this embodiment, the number of stator slots of the stator corresponding to the motor rotor is 54. The iron core height of the motor rotor is 80 mm, the diameter is 149.2 mm, the total angle A ≤ 6.67°, the number of segments N = 80 / 18 ≈ 4, and the range of each skewed pole angle: 0 ≤ α1 ≤ 3.335°, 0 ≤ α2 ≤ 3.335°, 0 ≤ α2 ≤ 3.335°. After being parameterized and simulated by the simulation software, α1 = 1°, α2 = 2.3°, α3 = 1.66° are taken. As Figures 7 to 15 shown, the motor rotor provided by the embodiment of the present invention has obvious optimization effects on the high-order harmonic of the no-load back electromotive force and the high-order force harmonic compared with the one-word symmetric skewed poles.

[0065] Another object of the present invention is to propose a motor, and the motor includes the above-mentioned motor rotor or the determination method of the skewed pole angle of the above-mentioned motor rotor. Because the motor uses the above-mentioned motor rotor, the motor has the advantages of lower NVH indicators and its performance can also be improved.

[0066] To further confirm the excellent performance of the motor rotor of the present application and the motor with this motor rotor, measurements and comparisons are made on the non-skewed pole motor, the one-word skewed pole motor, and the motor in the present application. Specifically, see Figures 7 - 15 and Tables 1 - 3 as follows:

[0067] See Figures 13 - 15 Combined with Table 1, it can be seen that the torque ripple of the motor of the present application is smaller than that of the non-skewed pole motor and the single-skewed pole motor.

[0068] Table 1 Comparison Table of Torque Ripple

[0069] Non - skewed pole motor Single - skewed pole motor The motor of the present application Torque ripple (%) 4.54 3.52 3

[0070] See Figures 7 - 9 Combined with Table 2, it can be seen that the no-load back electromotive force harmonics of the motor of the present application are smaller than those of the non-skewed pole motor and the single-skewed pole motor. The distortion rate of the motor in the present application is also the smallest.

[0071] Table 2 Comparison Table of No-Load Back Electromotive Force Harmonics

[0072] Non - skewed pole motor Single - skewed pole motor The motor of the present application 5th harmonic 24.9 23.7 17.52 7th harmonic 30.5 27.5 14.2 11th harmonic 3.5 2.5 0.26 13th harmonic 13.1 8.8 2 17th harmonic 11.5 5.7 2.3 19th harmonic 40 15.7 3.8 Distortion rate 4.3 2.9 1.7

[0073] See Figures 10 - 12 Combined with Table 3, it can be seen that whether it is the (6, 2) harmonics, (0, 6) harmonics, (0, 12) harmonics, or (0, 18) harmonics, the high-order force harmonics of the motor of the present application are smaller than those of the non-skewed pole motor and the single-skewed pole motor.

[0074] Table 3 Comparison Table of High-Order Force Harmonics

[0075] Non - skewed pole motor Single - skewed pole motor The motor of the present application (6, 2)th harmonic 305138 287046 238156 (0, 6)th harmonic 12141 8909 6586 (0, 12)th harmonic 5037 4273 3736 (0, 18)th harmonic 4115 1133 421

[0076] Based on the above tests and analyses, it is further confirmed that the motor rotor in the present application and the motor with the motor rotor can further reduce the motor NVH index and improve the motor performance.

[0077] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0078] In the present invention, unless otherwise clearly defined and limited, the terms such as "install", "connect", "connection", "fix" and the like should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0079] In the present invention, unless otherwise clearly defined and limited, the first feature being “on” or “under” the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being “above”, “over” and “on top of” the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being “under”, “beneath” and “underneath” the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0080] In the description of this specification, the descriptions with reference to the terms “an embodiment”, “some embodiments”, “exemplifications”, “specific exemplifications” or “some exemplifications” etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or exemplification are included in at least one embodiment or exemplification of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or exemplification. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or exemplifications in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or exemplifications described in this specification.

[0081] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A motor rotor, characterized in that, It includes N segments of skewed pole units. The N segments of skewed pole units include a first skewed pole unit, ..., an (N - 1)-th skewed pole unit, and an N-th skewed pole unit arranged in sequence along the axial direction of the motor rotor. Here, N is an integer greater than or equal to 3. The skewed pole angle between the first skewed pole unit and the second skewed pole unit is α1, and the skewed pole angle between the (N - 1)-th skewed pole unit and the N-th skewed pole unit is α (N-1) , and the total skewed pole angle of the multi-segment skewed pole units is A. Here, A ≥ α1 / 2 + α1 +... + α (N-1) +α (N-1) / 2, 0 ≤ α1 ≤ 2*A / N,..., 0 ≤ α (N-1) ≤ 2*A / N, and there is at least α i ≠ α (N-i) , where i is a positive integer less than or equal to N - 1.

2. A motor rotor according to claim 1, characterized in that, Each inclined pole unit has the same number of multiple magnetic poles evenly distributed along the circumferential direction of the motor rotor. Each magnetic pole includes two pairs of magnet slots arranged in pairs and permanent magnets arranged in the magnet slots. The magnet slots penetrate through both end faces of the iron core lamination group along the axial direction of the motor rotor. Each pair of magnet slots arranged in pairs is inclined towards the opposite sides of the circumferential direction of the motor rotor with respect to the radial direction of the motor rotor, so as to be configured that the distance from the magnet slots to the axis of the motor rotor in the circumferential direction forms a gradually expanding V shape towards the radially outer side.

3. A motor rotor according to claim 2, characterized in that, Isolation slots are arranged on both sides of the magnet slots, and the isolation slots penetrate through the end face of the inclined pole unit along the axial direction of the motor rotor.

4. A motor rotor according to claim 2, characterized in that, It further includes a rotor shaft. The iron core lamination group is hollow and sleeved on the rotor shaft. A keyway is axially formed on the outer peripheral surface of the rotor shaft, and a positioning key connected to the keyway is arranged on the inner peripheral surface of the iron core lamination group connected to the rotor shaft.

5. A motor rotor according to claim 3, characterized in that, An auxiliary slot recessed radially towards the axis of the iron core lamination group is arranged on the outer peripheral surface of the iron core lamination group. The auxiliary slot extends along the axial direction of the motor rotor and corresponds to one end of the magnet slot far from the axis of the motor rotor.

6. The motor rotor according to claim 4, characterized in that, N≤7。 7. A motor rotor according to claim 5, characterized in that, The length of the inclined pole unit in the axial direction of the motor rotor is 10 - 20 mm.

8. A motor rotor according to claim 6, characterized in that, The inclined pole unit includes six magnetic poles.

9. A method for determining the skew pole angle of a motor rotor, which is used to determine the skew pole angle of the motor rotor according to any one of claims 1-8, characterized in that, The motor rotor includes N skew pole units, and the N skew pole units include a first skew pole unit, ..., a (N-1)th skew pole unit, and an Nth skew pole unit arranged in sequence along the axial direction of the motor rotor, where N is an integer greater than or equal to 3. The skew pole angle between the first skew pole unit and the second skew pole unit is α1, and the skew pole angle between the (N-1)th skew pole unit and the Nth skew pole unit is α (N-1) , the total skew pole angle of the multiple skew pole units is A, the number of winding slots of the motor stator used in cooperation with the motor rotor is B, and the total axial length of the multiple skew pole units along the motor rotor is C. The method includes the following steps: S1: Determine the range of the total skew angle A according to the number B of the winding slots of the motor stator, and the calculation formula is A ≤ 360 / B. Determine the range of the number N of segments of the rotor core according to the height C of the rotor core, and the calculation formula is: N = C / 18 (3 ≤ N ≤ 7, rounded to the nearest integer). Limit the skew angle range between any adjacent skew pole units according to the total skew angle A and the number N of core segments between the multi-segment skew pole units. Among them, A ≥ α1 / 2 + α1 +... + α (N-1) + α (N-1) / 2, 0 ≤ α1 ≤ 2*A / N,..., 0 ≤ α (N-1) ≤ 2*A / N; S2: Select the total inclined pole angle A within the range of the total inclined pole angle determined in S1, select the number of segments N within the range of the number of inclined pole unit segments determined in S1, preset each inclined pole angle, then establish a motor rotor model and calculate the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force; S3: Load the established model into the simulation software; S4: Select the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force in the output options of the parameterization interface of the simulation software and set them as optimization objectives, and set each inclined pole angle as a scanning parameter; S5: Run the simulation software to check the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force calculated; S6: If the check is not completed, return to S5 and check whether there is interference in the motor rotor model and whether the set angle of the inclined pole is correct; if the check is completed, set the sensitivity analysis conditions. After the sensitivity analysis conditions are set, perform a scanning operation to obtain different combinations of inclined pole angle values; S7: Obtain a calculation model of the inclined pole angle to the optimization objective according to the obtained combination of inclined pole angles, judge the accuracy of the model. If the accuracy is greater than 90%, enter step S8. If the accuracy is less than 90%, return to step S6 and reselect the angle range; S8: Select the optimal combination of inclined pole angles.

10. A method for determining the skew pole angle of a motor rotor according to claim 9, characterized in that, In S6, the setting of the sensitivity analysis conditions includes: S61: Add the range of each inclined pole angle obtained in S1 as the scanning range of the inclined pole angle; S62: Add the optimization target values of the no-load back electromotive force distortion rate, load torque ripple, and load electromagnetic radial force; S63: Select the Latin hypercube algorithm.

11. A method for determining the skew pole angle of a motor rotor according to claim 10, characterized in that, After S7 and before S8, it further includes: Further narrow the range of the inclined pole angle within the range of S61 and set the optimization objective, and perform a scanning operation.

12. A motor, characterized in that, Including the motor rotor according to any one of claims 2-8, or the method for determining the skew angle of the motor rotor according to any one of claims 9-11.

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