A kind of permanent magnet synchronous motor stator and rotor lamination and motor

Abstract

The application discloses a kind of permanent magnet synchronous motor stator and rotor lamination and motor, it is related to permanent magnet synchronous motor technical field, including stator and rotor, the rotor is formed by the splicing of multiple rotor laminations, including the second rotor lamination that forms constant air gap with stator and the first rotor lamination and third rotor lamination of non-uniform air gap.The application is three-section rotor, and the circular truncated cone rotor is symmetrically arranged on the two sides of the middle cylindrical rotor, which forms three groups of air gaps with the inner side of the stator, and can reduce the cogging torque and torque ripple by mutual cooperation.The shape of the magnetic steel groove of the rotor is V-shaped and double-V-shaped, which can improve the content of rotor harmonic magnetic field, reduce noise, V-shaped can reduce the overall cost, and double-V-shaped can improve power density.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet synchronous motor technology, specifically to a stator and rotor lamination for a permanent magnet synchronous motor and the motor itself. Background Technology

[0002] As a modern high-performance servo motor and high-torque direct drive motor, the permanent magnet synchronous motor has the characteristics of high peak torque, strong overload capacity, small torque fluctuation, large torque / weight ratio, high efficiency, high power factor, smooth low-speed operation, low vibration, low noise, short axial dimension, compact structure, and can be made into a multi-air gap combined structure to further improve torque. It has broad application prospects in power systems such as CNC machine tools, robots, flywheel energy storage systems, high-speed centrifuges, electric vehicles, all-electric ships, and underwater vehicles.

[0003] The rotor laminations in existing permanent magnet synchronous motors are basically all the same shape, which results in high cogging torque and high torque pulsation, leading to a short service life. Summary of the Invention

[0004] The purpose of this invention is to provide stator and rotor laminations for a permanent magnet synchronous motor and the motor itself, thereby solving the above-mentioned technical problems.

[0005] The objective of this invention can be achieved through the following technical solutions: A stator and rotor lamination for a permanent magnet synchronous motor includes a stator and a rotor. The rotor is composed of multiple rotor laminations spliced ​​together, including a second rotor lamination that forms a constant air gap with the stator, and a first rotor lamination and a third rotor lamination with non-uniform air gaps.

[0006] As a further aspect of the present invention: the first rotor lamination and the third rotor lamination are located on both sides of the second rotor lamination.

[0007] As a further aspect of the present invention: the first rotor lamination and the third rotor lamination are both frustum-shaped, and the second rotor lamination is cylindrical.

[0008] As a further aspect of the present invention: the side of the first rotor lamination and the third rotor lamination closer to the second rotor lamination is the larger diameter side, and the side farther away is the smaller diameter side.

[0009] As a further aspect of the present invention: the air gaps between the first rotor lamination, the second rotor lamination, and the third rotor lamination and the stator lamination are g1, g2, and g3, respectively. The lengths of the first rotor lamination, the second rotor lamination, and the third rotor lamination are L1, L2, and L3, respectively; the total length of the rotor is L0, which satisfies L0=2*[(g1*L1)+(g2*L2)+(g3*L3)].

[0010] As a further aspect of the present invention: the magnet slots of the first rotor lamination and the third rotor lamination are V-shaped, and the magnet slots of the second rotor lamination are double V-shaped.

[0011] As a further aspect of the present invention: a magnetic isolation bridge is provided at the slot opening of the magnet slot of the first rotor lamination, the second rotor lamination, or the third rotor lamination.

[0012] As a further aspect of the present invention: the stator surface array has multiple winding slots, and the winding slots are pear-shaped slots.

[0013] As a further embodiment of the present invention: a permanent magnet synchronous motor is obtained by pressing a rotor into the stator.

[0014] As a further aspect of the present invention: the number of winding slots of the motor is Q1, and the number of rotor poles is P, satisfying L1=L0*{[1 / (abs(sin((P / Q1)*(π / 2)))]}.

[0015] The beneficial effects of this invention are: This invention employs a three-segment rotor design, specifically frustum-shaped rotors symmetrically positioned on either side of a central cylindrical rotor. The rotors and stator inner surfaces form three sets of air gaps, which, in combination, facilitate the formation of a sine wave in the motor's back electromotive force waveform, thereby reducing other harmonic content and consequently lowering cogging torque and torque ripple. Furthermore, by configuring the rotor's magnet slots in a V-shape or double-V-shape, the rotor's harmonic magnetic field content can be improved, reducing noise. The V-shape reduces overall cost, while the double-V-shape increases power density. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic cross-sectional view of the entire structure of the present invention; Figure 3 This is a schematic diagram of the overall cross-sectional planar structure of the present invention; Figure 4 yes Figure 3 A partial structural diagram; Figure 5 This is a front view of the V-shaped magnet slot rotor lamination and stator of the present invention; Figure 6 This is a front view of the double V-shaped magnet slot rotor and stator of the present invention; Figure 7 This is a front view of the stator of the present invention; Figure 8 This is a front view of the rotor lamination with double V-shaped magnet slots of the present invention; Figure 9 This is a side view of the rotor lamination with double V-shaped magnet slots of the present invention; Figure 10 This is a front view of the V-shaped magnet slot rotor lamination of the present invention; Figure 11 This is a side view of the V-shaped magnet slot rotor lamination of the present invention; Figure 12 These are the curves showing the influence of the air gap on the cogging torque of the present invention and existing technologies; Figure 13 This is the curve showing the influence of the air gap on torque pulsation in this invention and existing technologies.

[0018] In the picture: 1. Stator; 11. Winding slots; 2. Rotor; 21. First rotor lamination; 22. Second rotor lamination; 23. Third rotor lamination; 24. Magnet slot. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a high-performance, low-noise permanent magnet synchronous motor, which is particularly suitable for applications with high requirements for smooth operation, vibration and noise control, and cost control, such as precision industrial drive equipment and electric vehicle auxiliary motors. This permanent magnet synchronous motor has the following advantages: reduced cost, simple process, increased power density, reduced cogging torque, reduced torque pulsation, reduced harmonic magnetic field content, and low noise.

[0021] Specifically, see Figure 1-2 As shown, the permanent magnet synchronous motor includes a stator 1 and a rotor 2. The rotor 2 is composed of multiple rotor laminations spliced ​​together, including a second rotor lamination 22 that forms a constant air gap with the stator 1, and a first rotor lamination 21 and a third rotor lamination 23 with non-uniform air gaps. By forming three sets of air gaps with the inner side of the stator, the back EMF waveform of the motor can be more easily formed into a sine wave, thereby weakening other harmonic content and reducing cogging torque and torque pulsation.

[0022] See Figure 1-6As shown, the rotor 2 is composed of three independent rotor lamination assemblies spliced ​​along the axial direction. Each of the three rotor lamination assemblies is formed by stacking and fixing multiple rotor laminations. Then, they are pressed onto the rotating shaft in the order of first rotor lamination 21 (left), second rotor lamination 22 (middle), and third rotor lamination 23 (right), ensuring coaxiality. The first rotor lamination 21 and the third rotor lamination 23 are located on both sides of the second rotor lamination 22, forming a symmetrical arrangement. See Figure 8-11 As shown, specifically: the second rotor lamination 22 is cylindrical, and a uniform, constant air gap g2 is formed between its outer circular surface and the inner circular surface of the stator 1. This section is the main region for generating electromagnetic torque; The first rotor lamination 21 and the third rotor lamination 23 are symmetrically arranged frustum shapes (or truncated cone shapes). The end of each lamination closer to the second rotor lamination 22 is the larger diameter end, and the end farther away is the smaller diameter end. Therefore, they form axially gradually varying non-uniform air gaps g1 and g3 between them and the inner circle of the stator, with the air gap being smaller near the middle section and larger at the far end.

[0023] This combination of a uniform air gap and symmetrically tapered air gaps at both ends effectively modulates the harmonic distribution of the air gap magnetic permeability, weakening specific subharmonic magnetic fields that cause cogging torque and torque pulsation. The coordination of the three air gaps makes the change in magnetic reluctance of the magnetic circuit smoother when the rotor rotates, thereby significantly reducing motor vibration and noise.

[0024] The air gaps between the first rotor lamination 21, the second rotor lamination 22, and the third rotor lamination 23 and the stator lamination 1 are g1, g2, and g3, respectively. The air gap ranges of g1, g2, and g3 are all selected within a reasonable range of 1 mm to 3 mm. To further optimize performance, the ratio of the long air gap (referring to the effective value or large end value of g1 and g3) to the short air gap (g2) should satisfy the constraint related to the number of pole pairs: (long air gap / short air gap) ≈ tan(360° / P). This relationship is derived from the derivation of the sinusoidal air gap magnetic flux density waveform requirement and helps to sinusoidalize the magnetic field.

[0025] The lengths of the first rotor lamination 21, the second rotor lamination 22, and the third rotor lamination 23 are L1, L2, and L3, respectively, in mm; the total length of rotor 2 is L0, which satisfies L0=2*[(g1*L1)+ (g2*L2)+ (g3*L3)]. The air gap is an important parameter for energy conversion in motor design. The rotor length is designed in relation to the air gap, and the rotor is most reasonably sized within this dimension.

[0026] In this embodiment, the magnet slots 24 of the first rotor lamination 21 and the third rotor lamination 23 are V-shaped, which is beneficial for utilizing reluctance torque and has a simple structure and low manufacturing cost; the magnet slots 24 of the second rotor lamination 22 are double V-shaped (i.e., two V-shaped symmetrical arrangements), which can provide a stronger magnetizing effect, significantly increase the magnetic flux density in the main torque region, thereby improving the average torque and power density of the motor. At the same time, the double V structure is also beneficial for suppressing specific harmonics.

[0027] Whether it is a double V-shaped magnet slot or a V-shaped magnet slot, both ends of the magnet slot are provided with bends. The purpose of this is to reduce magnet leakage, maximize the back electromotive force of the motor, and thus improve the motor's torque and output power.

[0028] In the V-shaped magnet slot rotor laminations, magnetic isolation bridges are formed at the edges of the magnet slots near the rotor's outer diameter and inner diameter. Similarly, in the double V-shaped magnet slot rotor laminations, magnetic isolation bridges are also formed at the edges of the magnet slots near the rotor's outer and inner diameter. These magnetic isolation bridges are part of the rotor core, but their width is carefully designed to ensure magnetic saturation at the normal operating point. Their functions are: a) to mechanically fix the permanent magnets; and b) to limit the magnetic flux generated by the permanent magnets, especially leakage flux, from directly closing through the short path of the rotor core, forcing more flux to pass through the air gap into the stator and participate in the main energy conversion. This effectively improves the utilization rate of the permanent magnets, increases the air gap magnetic flux density, and thus enhances the motor's back EMF, torque, and output power.

[0029] See Figure 7 As shown, the stator 1 is made of laminated silicon steel sheets to reduce eddy current losses. The outer edge of the stator core can be circular or polygonal, and the inner edge has multiple pear-shaped slots 11 evenly distributed along the circumference. The opening of the pear-shaped slot is narrower and the lower part of the slot is wider. This shape is beneficial for inserting the pre-wound coil windings from the slot opening after the stator and rotor are pressed together (i.e., the "post-insertion" process).

[0030] Stator manufacturing: S1. Stamping: Stator laminations with pear-shaped grooves are punched out using a die.

[0031] S2. Core stacking: Multiple stator laminations are aligned on a tooling and pressed together by means of riveting, welding or bonding to form a stator core with axial length.

[0032] S3. Insulation treatment: Place an insulating liner in the pear-shaped groove 11 or perform overall insulation treatment.

[0033] S4. Winding Embedding: The fabricated coils (centralized or distributed windings) are embedded one by one into the pear-shaped slots 11 from the slots inside the stator core. Compared with the traditional method of winding first and then assembling the stator and rotor, this process simplifies the operation, reduces the precision requirements of the winding equipment, improves production efficiency and flexibility, and avoids damage to the windings during assembly. S5. Press stator 1 and rotor 2 together to obtain the motor. The motor has Q1 winding slots and P rotor poles, satisfying L1=L0*{[1 / (abs(sin((P / Q1)*(π / 2)))]}; This formula, through the matching of stator and rotor cores, makes it easier to form a sinusoidal distributed no-load back EMF waveform and an air gap magnetic flux density waveform with excellent sinusoidality, which helps to reduce motor vibration and noise.

[0034] The following measurements were taken of the cogging torque (mNm) and torque pulsation (mNm) of the permanent magnet synchronous motor in this embodiment and a conventional permanent magnet synchronous motor (whose stator contains only a cylindrical rotor) under different air gaps and (g1+g2+g3) conditions. The measurement results are shown in Tables 1 and 2. Table 1 Table 2 As shown in the table above, the specific curves illustrating the influence of the air gap on the cogging torque are as follows: Figure 12 As shown in the figure, the influence curve of the air gap on torque pulsation is as follows: Figure 13 As shown in the data above, it is clear that the combination of these three air gaps makes it easier for the back EMF waveform of the motor to form a sine wave, thereby weakening other harmonic content and reducing cogging torque and torque pulsation.

[0035] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A stator and rotor lamination for a permanent magnet synchronous motor, comprising a stator (1) and a rotor (2), characterized in that, The rotor (2) is composed of multiple rotor laminations spliced ​​together, including a second rotor lamination (22) that forms a constant air gap with the stator (1) and a first rotor lamination (21) and a third rotor lamination (23) with non-uniform air gaps. The first rotor lamination (21) and the third rotor lamination (23) are located on both sides of the second rotor lamination (22); The first rotor lamination (21) and the third rotor lamination (23) are both frustum-shaped, and the second rotor lamination (22) is cylindrical; The side of the first rotor lamination (21) and the third rotor lamination (23) closer to the second rotor lamination (22) is the larger diameter side, and the side farther away is the smaller diameter side; The magnet slots (24) of the first rotor lamination (21) and the third rotor lamination (23) are V-shaped, and the magnet slots (24) of the second rotor lamination (22) are double V-shaped. A magnetic bridge is provided at the slot opening of the magnetic slot (24) of the first rotor lamination (21), the second rotor lamination (22), or the third rotor lamination (23); The stator (1) has multiple winding slots (11) arrayed on its surface, and the winding slots (11) are pear-shaped slots; The motor has Q1 winding slots and P rotor poles, satisfying L1=L0*{[1 / (abs(sin((P / Q1)*(π / 2)))]}.

2. The stator and rotor laminations for a permanent magnet synchronous motor according to claim 1, characterized in that, The air gaps between the first rotor lamination (21), the second rotor lamination (22), and the third rotor lamination (23) and the stator (1) are g1, g2, and g3, respectively; The lengths of the first rotor lamination (21), the second rotor lamination (22) and the third rotor lamination (23) are L1, L2 and L3 respectively; the total length of the rotor (2) is L0, which satisfies L0=2*[(g1*L1)+ (g2*L2)+ (g3*L3)].

3. A permanent magnet synchronous motor, characterized in that, The rotor (2) is obtained by pressing the stator and rotor laminations as described in any one of claims 1-2 into the stator (1).

Images