Permanent magnet v-shaped embedded arrangement of rotor assembly, permanent magnet synchronous motor

Abstract

The application provides a rotor assembly with V-shaped embedded permanent magnets and a permanent magnet synchronous motor, and belongs to the field of motor design. The rotor assembly comprises a rotor core, the rotor core has a plurality of magnetic poles arranged along the circumference thereof, two V-shaped magnetic steel grooves are arranged below each magnetic pole, the opening of the V shape faces the outer side of the rotor core, a permanent magnet is arranged in each magnetic steel groove, and the radially outer ends of the two magnetic steel grooves are in communication with the outer side of the rotor core. Since there is no magnetic bridge at the radially outer end of the magnetic steel groove, the magnetic circuit of the motor is optimized, the main part of the magnetic leakage is eliminated, the magnetic lines cannot be closed at this position, the magnetic leakage of the motor is reduced, the utilization rate of the rotor magnetic flux is improved, the local temperature rise at this position is avoided, and the efficiency of the motor is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of motor design, and particularly relates to a rotor assembly with V-shaped embedded permanent magnets and a permanent magnet synchronous motor. BACKGROUND

[0002] At present, the rotor excitation of the permanent magnet synchronous motor is mostly the embedded permanent magnet excitation. Since the rotor has a magnetic steel slot, and in order to ensure the structural strength of the rotor core, the magnetic bridge is mostly reserved at the connection of the adjacent magnetic poles of the outer circle of the rotor for the purpose of strength improvement. Especially for the magnetic poles with heavy magnetic steel such as the V-shaped multi-piece magnetic steel, the magnetic bridge can effectively ensure the anti-deformation ability of the rotor core in the rotating process and prevent the magnetic steel from separating from the core. However, in the process of motor operation, the magnetic flux density at the magnetic bridge is large, the magnetic resistance is large, the local temperature rise of the motor is high, the magnetic flux leakage is high, the utilization rate of the rotor excitation magnetic flux is low, and the motor efficiency is reduced. SUMMARY

[0003] Therefore, the application provides a rotor assembly with V-shaped embedded permanent magnets and a permanent magnet synchronous motor, which can solve the technical problem that the rotor core of the rotor assembly with V-shaped embedded permanent magnets in the prior art has a magnetic bridge structure at the connection of the adjacent magnetic poles of the outer circle, the magnetic flux density and the magnetic resistance at the magnetic bridge are large in the process of motor operation, the local temperature rise of the motor is high, the magnetic flux leakage is high, the utilization rate of the rotor excitation magnetic flux is low, and the motor efficiency is reduced.

[0004] In order to solve the above problems, the application provides a rotor assembly with V-shaped embedded permanent magnets, which comprises a rotor core. The rotor core has a plurality of magnetic poles arranged along the circumference thereof. Two V-shaped magnetic steel slots are arranged under each magnetic pole. The opening of the V shape faces the outer circle side of the rotor core. A permanent magnet is arranged in each magnetic steel slot. The radially outer ends of the two adjacent magnetic steel slots of each adjacent magnetic pole are communicated with the outer circle side of the rotor core through a notch on the outer circle side wall of the rotor core.

[0005] In some embodiments, the outer circle side wall of the rotor core has a notch penetrating along the axial direction thereof. The radially outer ends of the two adjacent magnetic steel slots of each adjacent magnetic pole are communicated with the outer circle side of the rotor core through the notch.

[0006] In some embodiments, the radially outer end of the magnetic steel slot has a first limiting protrusion and a second limiting protrusion corresponding to the circumferential two sides of the permanent magnet, respectively. The first limiting protrusion and the second limiting protrusion are oppositely spaced to form radial anti-disengagement of the radially outer end of the permanent magnet.

[0007] In some embodiments, the minimum distance between the first limiting protrusion and the second limiting protrusion is L, and the pole thickness of the permanent magnet is h, and h / 3≤L≤2h / 3.

[0008] In some embodiments, the part of the rotor core between the two magnetic steel grooves under each magnetic pole is a sector-shaped core part, a connecting bridge is formed between the radially inner ends of the two magnetic steel grooves, the sector-shaped core part is connected to the central part of the rotor core through the connecting bridge, the connecting bridge has a circumferential minimum width H, H = mω 2 r / γ, the line segment between the two closest points of the two adjacent magnetic steel grooves is a first line segment, wherein m is the mass of the sector-shaped core part, ω is the maximum rotational angular velocity of the rotor core, r is the length of the line segment connecting the center of the central hole of the rotor core to the midpoint of the first line segment, and γ is the maximum tensile force per unit length of the material of the rotor core.

[0009] In some embodiments, the included angle formed between the two magnetic steel grooves under each magnetic pole is θ, the radial length of the permanent magnet is l, the outer circle radius of the rotor core is R, and the maximum centrifugal force borne by the sector-shaped core part during rotation of the rotor core is F, and

[0010]

[0011] In some embodiments, a magnetic isolation hole is formed at the radially inner end of the magnetic steel groove, and the magnetic isolation hole is in communication with the magnetic steel groove.

[0012] The application also provides a permanent magnet synchronous motor comprising the above-mentioned permanent magnet V-shaped embedded arrangement rotor assembly.

[0013] The permanent magnet V-shaped embedded arrangement rotor assembly and the permanent magnet synchronous motor provided by the application have no magnetic isolation bridge at the radially outer end of the magnetic steel groove, thereby optimizing the magnetic circuit of the motor, eliminating the main part of the magnetic leakage, preventing the magnetic lines from being closed at this position, reducing the magnetic leakage of the motor, improving the utilization rate of the rotor magnetic flux, avoiding local temperature rise at this position, and thus improving the efficiency of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 FIG. 1 is an axial projection schematic view of the permanent magnet V-shaped embedded arrangement rotor assembly of an embodiment of the application;

[0015] Figure 2 FIG. 2 is a partial enlarged view of position A in FIG. 1; Figure 1

[0016] Figure 3 FIG. 4 is the air gap magnetic field strength simulation result of the rotor assembly adopting the technical solution of the application, i.e., the rotor assembly without the magnetic isolation bridge;

[0017] Figure 4 ​The air gap magnetic field strength simulation result of the rotor assembly with the magnetic bridge (i.e., the rotor assembly without removing the magnetic bridge, referred to as a conventional scheme);

[0018] Figure 5 The motor efficiency comparison chart of the motor adopting the technical scheme of the present application and the motor not adopting the technical scheme of the present application at various frequency points.

[0019] The reference signs are as follows:

[0020] 1, rotor core; 10, notch; 11, magnetic steel slot; 111, first limiting convex; 112, second limiting convex; 12, fan-shaped core part; 13, connecting bridge; 14, magnetic isolation hole; 2, permanent magnet. DETAILED DESCRIPTION

[0021] For reference, Figures 1 to 5 According to the embodiment of the present application, a permanent magnet V-shaped embedded arrangement rotor assembly is provided, which comprises a rotor core 1, the rotor core 1 has a plurality of magnetic poles arranged along the circumference thereof, two magnetic steel slots 11 in a V-shaped arrangement are constructed under each magnetic pole, the opening of the V-shaped arrangement faces the outer circular side of the rotor core 1, and a permanent magnet 2 is arranged in each magnetic steel slot 11 to fully exert the magnetic gathering effect of the V-shaped arrangement permanent magnet. The radially outer end of the two magnetic steel slots 11 (i.e., the end facing outward in the radial direction of the rotor core 1) is in communication with the outer circular side of the rotor core 1, that is, the radially outer end of the magnetic steel slot 11 no longer has the magnetic isolation bridge in the prior art. In this technical scheme, since there is no magnetic isolation bridge at the radially outer end of the magnetic steel slot 11, the magnetic circuit of the motor is optimized, the main part of the magnetic leakage is eliminated, the magnetic lines cannot be closed at this position, the magnetic leakage of the motor is reduced, the utilization rate of the rotor magnetic flux is improved, the local temperature rise at this position is avoided, and thus the efficiency of the motor is improved.

[0022] For reference, Figure 3 and Figure 4 Among them, Figure 3 The air gap magnetic field strength simulation result of the rotor assembly adopting the technical scheme of the present application, i.e., the rotor assembly without the magnetic isolation bridge (referred to as the present application scheme), Figure 4 The air gap magnetic field strength simulation result of the rotor assembly with the magnetic bridge (i.e., the rotor assembly without removing the magnetic bridge, referred to as a conventional scheme), after removing the magnetic isolation bridge, the outer circular side of the rotor core 1 does not have magnetic leakage, the air gap magnetic field strength of the present application scheme is improved by 2.6% compared with the conventional scheme, and specifically, referring to Figure 3 The air gap magnetic field strength of the present application scheme is between 8.1795E+5 (i.e., 8.1795*10 5) and 7.3616E+5, the air gap magnetic field strength of the conventional scheme is about 7.1738E+5, the air gap magnetic field strength of the present scheme is 7.3616E+5, and the improvement effect is approximately (7.3616-7.1738) / 7.1738*100% = 2.6%. The efficiency of the motor at each frequency point is improved, and reference is made to Figure 5 As shown in the figure, the motor APF (annual energy consumption rate) is increased by about 0.2%.

[0023] In one embodiment, the outer circular side wall of the rotor core 1 has a notch 10 extending through the axial direction thereof, and the radially outer ends of the two adjacent magnetic steel grooves 11 of the two adjacent magnetic poles are both communicated with the outer circular side of the rotor core 1 through the notch 10, that is, the radially outer ends of the two adjacent magnetic steel grooves 11 are both located at the notch 10, which can prevent the setting of an independent notch 10 for each radially outer end of the magnetic steel groove 11 from reducing the overall rigidity and strength of the rotor core 1, thereby ensuring that the overall structure of the rotor core 1 is more stable and reliable. Specifically, the radially outer end of the magnetic steel groove 11 has a first limiting protrusion 111 and a second limiting protrusion 112 corresponding to the circumferential two sides of the permanent magnet 2, respectively, and the first limiting protrusion 111 and the second limiting protrusion 112 are arranged at a relative interval to form a radial anti-disengagement for the radially outer end of the permanent magnet 2. Further, the radially inner side surface of each of the first limiting protrusion 111 and the second limiting protrusion 112 is in contact with the radially outer end surface of the permanent magnet 2, thereby realizing the radial force limiting of the permanent magnet 2 and preventing the permanent magnet 2 from being thrown out during the rotation of the rotor core 1. In a preferred embodiment, the minimum distance between the first limiting protrusion 111 and the second limiting protrusion 112 is L (unit: mm), and the pole thickness of the permanent magnet 2 is h (unit: mm, that is Figure 1 the thickness of the permanent magnet 2 in the circumferential direction of the azimuthal direction), h / 3≤L≤2h / 3. Specifically, when L is less than h / 3, the magnetic leakage of the permanent magnet 2 increases more, which affects the performance of the motor, and when L is greater than 2h / 3, the structural strength of the aforementioned limiting protrusion is reduced, which reduces the maximum operating frequency of the motor.

[0024] In some embodiments, under each magnetic pole, the part of the rotor core 1 between the two magnetic steel grooves 11 is a fan-shaped core part 12, and a connecting bridge 13 is formed between the radially inner ends of the two magnetic steel grooves 11. The fan-shaped core part 12 is connected to the central part of the rotor core 1 through the connecting bridge 13, and the connecting bridge 13 has a minimum width H in the circumferential direction (that is, the circumferential direction of the rotor core 1), H = mω 2r / γ, the line connecting the two closest points between the two adjacent magnetic steel slots 11 is the first line segment, where m is the mass of the fan-shaped core portion 12 (in a specific example, in kg), ω is the maximum rotational angular velocity of the rotor core 1 (in a specific example, in rad / s), r is the length of the line connecting the center of the central hole of the rotor core 1 and the midpoint of the first line segment (in a specific example, in mm), and γ is the maximum tensile force per unit length that the material of the rotor core 1 can withstand (in a specific example, in N / mm). In this technical solution, the minimum width H of the connecting bridge 13 is determined according to the maximum centrifugal force F that the material of the rotor core 1 can withstand, and the determination of the aforementioned minimum width can increase the strength of the rotor and optimize the magnetic density at the connecting bridge 13 (widen the connecting bridge 13 to reduce the magnetic density, increase the width of the connecting bridge 13 to increase the magnetic density), so that the width design of the connecting bridge 13 is more reasonable, that is, the structural strength and the optimization of the magnetic density can be considered, and the phenomenon of excessive saturation of the magnetic density of the rotor core 1 at this position, which leads to excessive temperature rise of the core, is effectively prevented.

[0025] Referring to Figure 1 As shown in the figure, the included angle between the two magnetic steel slots 11 under each magnetic pole is θ (in a specific example, in °), the radial length of the permanent magnet 2 is l (in a specific example, in mm), the outer circle radius of the rotor core 1 is R (in mm), and the maximum centrifugal force that the fan-shaped core portion 12 can withstand during the rotation of the rotor core is F (in a specific example, in N), And In this way, the radial force that the permanent magnet 2 can withstand (that is, the anti-deformation ability of the rotor core) can be maximally reduced, the magnetic field generated by the motor can be ensured to be close to a sine wave, and the harmonics of the motor can be reduced.

[0026] In some embodiments, the radial inner end of the magnetic steel slot 11 is formed with a magnetic isolation hole 14, the magnetic isolation hole 14 is in communication with the magnetic steel slot 11, and the shape and size of the magnetic isolation hole are not particularly limited and can be selected according to actual needs, for example, circular, square, etc. However, it can be understood that regardless of the specific shape of the magnetic isolation hole 14, the shapes of the two magnetic isolation holes 14 arranged opposite to each other should be symmetrical to each other and should have a unique closest point to achieve the unique determination of H.

[0027] It can be understood that in order to further improve the mechanical structural strength of the rotor core and the position reliability of the magnetic steel, rotor end plates can also be arranged at both ends of the rotor core and fastened by corresponding rivets.

[0028] According to the embodiments of the application, a permanent magnet synchronous motor is also provided, which comprises the above-mentioned rotor assembly with the V-shaped embedded arrangement of the permanent magnets.

[0029] Those skilled in the art can easily understand that the advantageous technical features of the above-mentioned modes can be freely combined and superimposed without conflict.

[0030] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A rotor assembly of a permanent magnet V-embedded arrangement, characterized by, The application relates to a rotor core (1) comprising a plurality of magnetic poles arranged along the circumference of the rotor core (1), two V-shaped magnetic steel grooves (11) being arranged under each magnetic pole, the opening of the V shape facing the outer side of the rotor core (1), a permanent magnet (2) being arranged in each magnetic steel groove (11), the radially outer ends of the two magnetic steel grooves (11) being in communication with the outer side of the rotor core (1), the part of the rotor core (1) between the two magnetic steel grooves (11) under each magnetic pole being a sector-shaped core part (12), a connecting bridge (13) being formed between the radially inner ends of the two magnetic steel grooves (11), the sector-shaped core part (12) being connected to the central part of the rotor core (1) through the connecting bridge (13), the connecting bridge (13) having a minimum width H in the circumferential direction, H = m omega 2 r / gamma, the line connecting the two closest points between two adjacent magnetic steel grooves (11) being a first line segment, wherein m is the mass of the sector-shaped core part (12), omega is the maximum rotational angular velocity of the rotor core (1), r is the length of the line connecting the center of the central hole of the rotor core (1) and the midpoint of the first line segment, and gamma is the maximum tensile force per unit length of the material of the rotor core (1).

2. The rotor assembly of claim 1, wherein The rotor core (1) has a notch (10) penetrating through the axial direction on the outer circular side wall, and the radial outer ends of the two adjacent magnetic pole slots (11) of the two adjacent magnetic poles are communicated with the outer circular side of the rotor core (1) through the notch (10).

3. The rotor assembly of claim 2, wherein, The radial outer end of the magnetic pole slot (11) has a first limiting convex (111) and a second limiting convex (112) corresponding to the circumferential two sides of the permanent magnet (2) respectively, and the first limiting convex (111) and the second limiting convex (112) are oppositely spaced to form radial anti-drop of the radial outer end of the permanent magnet (2).

4. The rotor assembly of claim 3, wherein The minimum distance between the first limiting convex (111) and the second limiting convex (112) is L, the pole thickness of the permanent magnet (2) is h, and h / 3≤L≤2h / 3.

5. The rotor assembly of claim 1, wherein The included angle between the two magnetic pole slots (11) under each magnetic pole is θ, the radial length of the permanent magnet (2) is l, the outer circular radius of the rotor core (1) is R, and the maximum centrifugal force borne by the sector core part (12) during the rotation of the rotor core is F, and .

6. The rotor assembly of any one of claims 1 to 5, wherein, The radial inner end of the magnetic pole slot (11) is formed with a magnetic isolation hole (14) which is communicated with the magnetic pole slot (11).

7. A permanent magnet synchronous motor, characterized by, A rotor assembly comprising a permanent magnet V-type inlaid arrangement according to any one of claims 1 to 6.

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