A rotor structure of a hybrid laminated field modulation type permanent magnet reluctance synchronous motor

Abstract

The present invention discloses a rotor structure of a hybrid laminated magnetic field modulation type permanent magnet reluctance synchronous motor, which includes a central rotating shaft and a rotor core sleeved on the central rotating shaft; P U-shaped through slots are uniformly arranged in the rotor core around the central axis, where P is the number of rotor magnetic poles, and permanent magnets are arranged at the bottom positions of the U-shaped through slots; around the central axis, a rectangular through slot group is arranged in each U-shaped region formed by the U-shaped through slots, and the number of rectangular through slot groups is P; the rectangular through slot group includes a plurality of rectangular through slots, and axial lamination groups are embedded in the rectangular through slots. By embedding axial lamination groups inside the rotor, the present invention reduces the torque ripple of the motor, makes the motor operation smoother, effectively controls noise and vibration; it can also reduce the harmonic content of the air-gap magnetic density, thereby reducing the eddy current loss of the motor, improving the operation efficiency of the motor, and suppressing the temperature rise of the motor.

Description

Technical Field

[0001] The present invention relates to the field of permanent magnet motors, and particularly to a rotor structure of a hybrid laminated field modulation type permanent magnet reluctance synchronous motor. Background Art

[0002] The torque ripple of a permanent magnet reluctance synchronous motor includes two parts: cogging torque and ripple torque. The cogging torque is generated by the tangential component of the force between the stator teeth and the permanent magnets, and the ripple torque is generated by the interaction of the stator and rotor harmonic magnetomotive forces and the uneven magnetic resistance distribution caused by the stator and rotor slotting. To reduce the magnetic field harmonics, existing technologies mostly adopt means such as adjusting the shape and position of the through slots in the rotor core, forming design schemes such as adjacent pole asymmetry or pole inner asymmetry, resulting in complex motor processing technology and difficult processing. Moreover, the asymmetric design scheme leads to inconsistent performance when the motor rotates forward and backward, and cannot be competent for applications that require bidirectional rotation. The asymmetric design scheme also makes the manufacturing and installation of permanent magnets difficult, further restricting the application and promotion.

[0003] Some technicians have proposed a technical scheme of opening a series of punching slots on the rotor surface. By setting through slots with different widths on the rotor surface, the air-gap magnetic resistance distribution characteristics are changed, thereby reducing the content of air-gap magnetic field harmonics and finally reducing the torque ripple. However, this technical scheme will induce a large amount of eddy currents on the surface of the rotor core, generating eddy current losses, reducing the operating efficiency of the motor, and also causing the motor temperature to rise too high, affecting the stable and reliable operation of the permanent magnets in the rotor core.

[0004] In applications with high requirements for reliability and stability, on the premise of ensuring the stable and reliable operation of the motor, reducing the content of magnetic field harmonics and torque ripple is a major technical problem in the field of modern motor design. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to provide a rotor structure of a hybrid laminated field modulation type permanent magnet reluctance synchronous motor, which can effectively reduce the output torque ripple of the motor and improve the operating stability of the motor.

[0006] Technical Solution: The present invention includes a central rotating shaft and a rotor core sleeved on the central rotating shaft; P groups of U-shaped through slots are evenly arranged in the rotor core around the central axis, P is the number of rotor poles, and permanent magnets are arranged at the bottom positions of the U-shaped through slots; around the central axis, a rectangular through slot group is arranged in each U-shaped region formed by the U-shaped through slots, and the number of rectangular through slot groups is P; the rectangular through slot group includes a plurality of rectangular through slots, and axial lamination groups are embedded in the rectangular through slots; among the rectangular through slots in the rectangular through slot group, the i-th rectangular through slot in the clockwise direction is the i-th rectangular through slot, and the axial lamination group arranged in the i-th rectangular through slot is the i-th axial lamination group, and the width w of the i-th axial lamination group i The calculation formula is:

[0007]

[0008] In the formula, R o represents the outer radius of the rotor core; R i represents the inner radius of the rotor core; α i represents the span angle between the j-th intersection point and the (j + 1)-th intersection point of the first waveform and the second waveform, where j = 2i - 1; the first waveform and the second waveform satisfy the following conditions:

[0009]

[0010] In the formula, f1 represents the reference frequency of the first waveform; E k represents the amplitude of a sine wave waveform with a frequency of kf1; x represents the position angle, 0° ≤ x ≤ 180°, H = 1, 2, 3...; the second waveform is a triangular wave, and the amplitude G of the second waveform = E k , and the frequency f2 of the second waveform = Mf1, M = 5m, m = 1, 2, 3...

[0011] The distance d between the i-th rectangular through slot and the (i + 1)-th rectangular through slot in the rectangular through slot group near the outer edge of the rotor core o is equal, and the distance d between the i-th rectangular through slot and the (i + 1)-th rectangular through slot in the rectangular through slot group near the central rotating shaft i is equal, so as to make the magnetic field evenly distributed and avoid local saturation of the rotor core.

[0012] The distance l between the bottom of the M / 2-th rectangular through slot in the rectangular through slot group near the central rotating shaft and the permanent magnet Z satisfies: l Z ≥ (l PM / 4). From the perspective of magnetic field distribution, restricting this dimension is to avoid core saturation between the axial lamination group and the permanent magnet, so that the permanent magnetic field can smoothly enter each axial lamination group, thereby achieving the purpose of modulation.

[0013] The axial lamination group is composed of axial laminations and magnetic isolation laminations, and the widths l ax and l is satisfy the following conditions:

[0014]

[0015] In the formula, B r is the remanence of the permanent magnet, B s is the saturation magnetic density of the axial lamination, and ∑l ax is the sum of the widths of the axial laminations in all the rectangular through slots of a rectangular through slot group. By restricting this dimension, axial lamination saturation is avoided.

[0016] The axial laminations are made of grain-oriented silicon steel sheets, and the orientation direction is consistent with the magnetization direction of the permanent magnets. The magnetic isolation laminations are made of weakly magnetic conductive materials. By using grain-oriented silicon steel sheets, the magnetic field direction is restricted, avoiding magnetic leakage at the sides of the axial laminations and the rotor core.

[0017] The rotor core is formed by laminating radial rotor punching sheets. Laminating sheets to make the rotor and stator cores is the current mainstream process, aiming to reduce the eddy current loss of the core.

[0018] Advantages: Compared with the prior art, the technical solution of the present invention has the following advantages: (1) By embedding an axial lamination group inside the rotor, the torque ripple of the motor is reduced, the motor runs more smoothly, and the noise and vibration are effectively controlled. Embedding the axial lamination group inside the rotor can also reduce the harmonic content of the air-gap magnetic density, thereby reducing the eddy current loss of the motor, improving the operating efficiency of the motor, and suppressing the motor temperature rise; (2) A general formula for the width of the axial lamination group is given, which can be applied to various types of interior permanent magnet motors, with strong versatility; (3) There is no need to process the permanent magnets, and the processing cost is low. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of the present invention;

[0020] Figure 2 is Figure 1 a partial enlarged view of;

[0021] Figure 3 is a schematic diagram of the first waveform and the second waveform in the present invention;

[0022] Figure 4 is a schematic structural diagram of the axial lamination group in the present invention;

[0023] Figure 5 is a schematic structural diagram of the rotor in Embodiment 1 of the present invention. Detailed Embodiments

[0024] The technical solution of the present invention will be described in detail below in conjunction with the detailed embodiments and the drawings in the specification.

[0025] As Figure 1As shown in the figure, the present invention includes a central rotating shaft 1 and a rotor core 2. The rotor core 2 is sleeved on the central rotating shaft 1; the central rotating shaft 1 and the rotor core 2 are installed with the same central axis; around the central axis, P sets of U-shaped through grooves 3 with the same shape and size are evenly arranged in the rotor core 2, where P is the number of rotor magnetic poles, and a permanent magnet 4 is arranged at the bottom position of the U-shaped through groove 3; around the central axis, P sets of rectangular through groove groups 5 with the same shape and size are evenly arranged in the rotor core 2. Among the multiple rectangular through grooves 7 arranged in each rectangular through groove group 5, the i-th rectangular through groove 7 in the clockwise direction is the i-th rectangular through groove 7, and the axial lamination group 6 arranged in the i-th rectangular through groove 7 is the i-th axial lamination group 6. The rotor core 2 is formed by laminating radial rotor punching sheets.

[0026] As Figure 2 shown, the width of the axial lamination group 6 in a rectangular through groove group 5 is shown, where the width w i of the i-th axial lamination group 6 is:

[0027] In the formula, R o is the outer radius of the rotor core, R i is the inner radius of the rotor core, α i is the span angle between the j-th intersection point and the (j + 1)-th intersection point of the first waveform and the second waveform, j = 2i - 1, where the first waveform and the second waveform satisfy the following conditions:

[0028]

[0029] In the formula, f1 is the reference frequency of the first waveform, E k is the amplitude of the sine wave waveform with a frequency of kf1, x is the position angle, 0° ≤ x ≤ 180°, H = 1, 2, 3...; the second waveform is a triangular wave, the amplitude G of the second waveform = E k , and the frequency f2 of the second waveform = Mf1, M = 5m, m = 1, 2, 3... Figure 3 shows the first waveform, the second waveform and the intersection points therebetween.

[0030] Among them, the distance d o between the i-th rectangular through groove 7 and the (i + 1)-th rectangular through groove 7 near the outer edge of the rotor core 2 is equal, and the distance d i between the i-th rectangular through groove 7 and the (i + 1)-th rectangular through groove 7 of each rectangular through groove group 5 near the central rotating shaft 1 is equal. The distance l Z between the bottom of the M / 2-th rectangular through groove 7 of the rectangular through groove group 5 near the central rotating shaft 1 and the permanent magnet 4 satisfies: l Z ≥ (l PM / 4).

[0031] As Figure 4As shown, the axial lamination group 6 is composed of axial laminations 8 and magnetic isolation laminations 9. The axial laminations 8 are made of grain-oriented silicon steel sheets, and the orientation direction is consistent with the magnetization direction of the permanent magnet 4. The magnetic isolation laminations 9 are made of weakly magnetically conductive materials such as mica sheets. The widths l of the axial laminations 8 and the magnetic isolation laminations 9 ax and l is satisfy the following conditions:

[0032]

[0033] In the formula, B r is the remanence of the permanent magnet, B s is the saturation magnetic density of the axial lamination, and ∑l ax is the sum of the widths of the axial laminations in all the rectangular through slots of a rectangular through slot group.

[0034] Embodiment 1:

[0035] As Figure 3 and Figure 5 shown, this embodiment is a 4-pole permanent magnet reluctance synchronous motor, P = 4, the outer diameter R of the rotor o = 140 mm, the inner diameter R i = 52 mm, and the magnetization direction length l of the permanent magnet PM = 5 mm. Figure 3 The figure shows the schematic diagrams of the first waveform and the second waveform, where the first waveform is a sine wave containing only the fundamental frequency, corresponding to H = 1; the frequency of the second waveform is 10 times that of waveform 1, corresponding to M = 10, and m = 2. Figure 3 As shown, the span angle α1 between the 1st intersection point and the 2nd intersection point of the first waveform and the second waveform is 4°, the span angle α2 between the 3rd intersection point and the 4th intersection point is 9°, the span angle α3 between the 5th intersection point and the 6th intersection point is 13°, the span angle α4 between the 7th intersection point and the 8th intersection point is 16°, the span angle α5 between the 9th intersection point and the 10th intersection point is 18°, the span angle α6 between the 11th intersection point and the 12th intersection point is 16°, the span angle α7 between the 13th intersection point and the 14th intersection point is 13°, the span angle α8 between the 15th intersection point and the 16th intersection point is 9°, and the span angle α9 between the 17th intersection point and the 18th intersection point is 4°. Therefore, the width w1 of the 1st axial lamination group is:

[0036]

[0037] And so on, the width w2 of the second axial lamination stack is 7.5 mm, the width w3 of the third axial lamination stack is 10.9 mm, the width w4 of the fourth axial lamination stack is 13.4 mm, the width w5 of the fifth axial lamination stack is 15.0 mm, the width w6 of the sixth axial lamination stack is 13.4 mm, the width w7 of the seventh axial lamination stack is 10.9 mm, the width w8 of the eighth axial lamination stack is 7.5 mm, and the width w9 of the ninth axial lamination stack is 3.3 mm. The distance d of the rectangular through slot from the outer edge of the rotor core o is all 4.4 mm, and the distance d of the rectangular through slot from the central rotating shaft of the rotor i is all 2.3 mm. The distance l between the bottom of the M / 2 = 5th rectangular through slot close to the central rotating shaft and the permanent magnet Z = 3.8 mm, satisfying: l Z ≥(l PM / 4). The width w of the permanent magnet PM = 24 mm, the remanence B r = 1.2 T, the axial lamination thickness l ax = 0.7 mm, the saturation magnetic density B s = 2.2 T, l is = 0.25 mm, ∑l ax = 62 mm satisfies B r w PM ≤B s ∑l ax and l is ≤l ax ≤4l is . The axial laminations are made of grain-oriented silicon steel sheets, and the orientation direction is the same as the magnetization direction of the permanent magnet. The magnetic isolation laminations are made of mica sheets.

Claims

1. A rotor structure of a hybrid laminated magnetic field modulation type permanent magnet reluctance synchronous motor, characterized in that: It includes a central rotating shaft (1) and a rotor core (2) sleeved on the central rotating shaft (1); P groups of U-shaped through grooves (3) are evenly arranged in the rotor core (2) around the central axis, P is the number of rotor magnetic poles, and permanent magnets (4) are arranged at the bottom positions of the U-shaped through grooves (3); around the central axis, a rectangular through groove group (5) is arranged in the U-shaped region formed by each U-shaped through groove (3), and the number of the rectangular through groove groups (5) is P; the rectangular through groove group (5) includes a plurality of rectangular through grooves (7), and axial lamination groups (6) are embedded in the rectangular through grooves (7). Among the plurality of rectangular through grooves (7) in the rectangular through groove group (5), the i-th rectangular through groove (7) is in the clockwise direction. The axial lamination group (6) provided in the i-th rectangular through groove (7) is the i-th axial lamination group (6), and the width w of the i-th axial lamination group (6) i The calculation formula is as follows: Wherein, R o represents the outer radius of the rotor core; R i represents the inner radius of the rotor core; α i represents the span angle between the j-th intersection point and the (j + 1)-th intersection point of the first waveform and the second waveform, where j = 2i - 1; The first waveform and the second waveform satisfy the following conditions: In the formula, f1 represents the reference frequency of the first waveform; E k represents the amplitude of a sine wave waveform with a frequency of kf1; x represents the position angle, 0° ≤ x ≤ 180°, H = 1, 2, 3...; the second waveform is a triangular wave, and the amplitude G of the second waveform = E k , and the frequency f2 of the second waveform = Mf1, M = 5m, m = 1, 2, 3...

2. The rotor structure of the hybrid laminated magnetic field modulation type permanent magnet reluctance synchronous motor according to claim 1, characterized in that: The distance d between the i-th rectangular through slot (7) and the (i + 1)-th rectangular through slot (7) in the rectangular through slot group (5) close to the outer edge of the rotor core (2) o is equal, and the distance d between the i-th rectangular through slot (7) and the (i + 1)-th rectangular through slot (7) in the rectangular through slot group (5) close to the central rotating shaft (1) i is equal.

3. The rotor structure of the hybrid laminated field modulation type permanent magnet reluctance synchronous motor according to claim 1, characterized in that: The distance l between the bottom of the M / 2-th rectangular through slot (7) of the rectangular through slot group (5) and the permanent magnet (4) near the central rotating shaft (1) Z satisfies: l Z ≥(l PM / 4), where l PM represents the length of the magnetization direction of the permanent magnet.

4. The rotor structure of the hybrid laminated magnetic field modulation type permanent magnet reluctance synchronous motor according to claim 1, characterized in that: The axial lamination stack (6) consists of axial laminations (8) and magnetic separation laminations (9), and the widths l of the axial laminations (8) and the magnetic separation laminations (9) ax and l is meet the following conditions: Wherein, B r is the residual magnetism of the permanent magnet, B s is the saturation magnetic density of the axial lamination, ∑l ax is the sum of the widths of the axial laminations in all the rectangular through slots of a rectangular through slot group, w PM is the width of the permanent magnet.

5. The rotor structure of the hybrid laminated field modulation type permanent magnet reluctance synchronous motor according to claim 4, characterized in that: The axial laminations (8) are made of grain-oriented silicon steel sheets, and the orientation direction is consistent with the magnetization direction of the permanent magnet (4); the magnetic isolation laminations (9) are made of weakly magnetic materials.

6. The rotor structure of the hybrid laminated field modulation type permanent magnet reluctance synchronous motor according to any one of claims 1 to 5, characterized in that: The rotor core (2) is formed by laminating radial rotor punching sheets.

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