阅读说明：本技术 一种磁钢内置式双u型分数槽集中绕组永磁电机 (Magnetic steel built-in type double-U-shaped fractional slot concentrated winding permanent magnet motor ) 是由 王敏 周荣明 耿伟伟 姜涛 于 2019-09-24 设计创作，主要内容包括：本发明公开一种磁钢内置式双U型分数槽集中绕组永磁电机,包括定子和转6,电机转子包括转子铁芯、内层磁钢、外层磁钢、磁钢槽。内层磁钢、外层磁钢都呈U型分布于转子铁芯部。每组磁钢包括4块磁钢,其中每组包括2块径向磁钢,两块切向磁钢。每组磁钢中相邻的两块磁钢之间设置有用于加强转子机械强度的磁桥,合适的磁桥宽度,既能保证电机转子的机械强度,又能使电机不至于产生较大的漏磁。无论是磁钢之间的磁桥宽度还是磁钢与转子外圆之间的磁桥宽度,外层的磁桥宽度大于内层的磁桥宽度。本发明通过增加内置式磁钢层数的方式,在增加了电机磁阻转矩的同时,又利用分段转子的方式减小了电机的脉动转矩和转子涡流损耗。(The invention discloses a magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor which comprises a stator and a rotor 6, wherein a motor rotor comprises a rotor core, inner layer magnetic steel, outer layer magnetic steel and magnetic steel slots. The inner layer magnetic steel and the outer layer magnetic steel are distributed on the rotor iron core part in a U shape. Each group of magnetic steel comprises 4 pieces of magnetic steel, wherein each group comprises 2 pieces of radial magnetic steel and two pieces of tangential magnetic steel. Be provided with the magnetic bridge that is used for strengthening rotor mechanical strength between two adjacent magnet steels in every group magnet steel, suitable magnetic bridge width can guarantee electric motor rotor's mechanical strength, can make the motor be unlikely to produce great magnetic leakage again. No matter the width of the magnetic bridge between the magnetic steels or the width of the magnetic bridge between the magnetic steels and the excircle of the rotor, the width of the outer magnetic bridge is larger than that of the inner magnetic bridge. The invention increases the reluctance torque of the motor by increasing the number of layers of the built-in magnetic steel, and reduces the pulsation torque and the eddy current loss of the motor by utilizing a segmented rotor mode.)

1. A magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor is characterized in that: comprises a stator (5) and a rotor (6); the rotor (6) comprises a rotor core (1), magnetic steel grooves (4) are uniformly distributed in the rotor core (1) along the circumference, the magnetic steel grooves (4) are double-layer U-shaped grooves, and the opening direction of the double-layer U-shaped grooves faces one side of the rotor (6); double-layer U-shaped groove inner layer and outer layer flat bottom partTwo pieces of radial magnetized magnetic steel (2a, 3a) are distributed in the center of the magnetic pole, two tangential magnetized magnetic steel (2b, 3b) are respectively arranged at two side parts of the inner layer and the outer layer of the double-layer U-shaped groove, a magnetic bridge is arranged between the two pieces of radial magnetized magnetic steel (2a, 3a), and a magnetic bridge is respectively arranged between the radial magnetized magnetic steel (2a, 3a) and the tangential magnetized magnetic steel (2b, 3 b); the angle of the polar arc occupied by the outer layer magnetic steel (3) is defined as a first polar arc angle theta₁The arc angle of the inner layer magnetic steel (2) is a second arc angle theta₂Wherein the first polar arc angle θ₁Satisfies the following conditions: 0.6 tau < theta₁< 0.8 × τ, second arc angle θ₂Satisfies the following conditions: 0.4 tau < theta₂< 0.6 x τ, where τ is 180 °/p, and p is the number of motor poles.

2. The magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor according to claim 1, characterized in that: the outer diameter d of the rotor (6)₁And inner diameter d₂Satisfies the following conditions: 0.65 × d₁＜d₂＜0.8*d₁The width of a magnetic bridge between two pieces of radial magnetized magnetic steel (2a) in the inner layer magnetic steel (2) is m₁The width of the magnetic bridge between the radial magnetized magnetic steel (2a) and the tangential magnetized magnetic steel (2b) is n₁Wherein m is₁Satisfies the following conditions: 0.003 × d₁＜m₁＜0.004*d₁，n₁Satisfies the following conditions: 0.0025 × d₁＜n₁＜0.0035*d₁(ii) a The width of a magnetic bridge between two pieces of radial magnetized magnetic steel (3a) in the outer layer magnetic steel (3) is m₂The width of the magnetic bridge between the radial magnetized magnetic steel (3a) and the tangential magnetized magnetic steel (3b) is n₂Wherein m is₂Satisfies the following conditions: 0.003 × d₁＜m₂＜0.004*d₁，n₂Satisfies the following conditions: 0.0025 × d₁＜n₂＜0.0035*d₁。

3. The magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor according to claim 2, characterized in that: satisfy m₁＜m₂And n is₁＜n₂。

4. According to claimThe magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor disclosed by any one of claims 1-3 is characterized in that: the distance between the tangential magnetized magnetic steel (3b) in the outer layer magnetic steel (3) and the excircle of the rotor is L₁The distance between the tangential magnetized magnetic steel (2b) in the inner layer magnetic steel (2) and the excircle of the rotor is L₂Wherein L is₁Satisfies the following conditions: 0.75 × g < L₁＜0.95*g，L₂Satisfies the following conditions: 0.7 × g < L₂< 0.9 × g, g being the thickness of the air gap between the stator (5) and the rotor (6).

5. The magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor according to claim 4, characterized in that: satisfy L₁＞L₂。

6. The magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor according to any one of claims 1 to 3, characterized in that: a bulge structure used for fixing the position of the magnetic steel is arranged in the magnetic steel groove (4), wherein the depth of the bulge structure on the radial magnetic steel groove (4a) for accommodating the radial magnetized magnetic steel (2a, 3a) is a₁The depth of the convex structure on the tangential magnetic steel groove (4b) for containing the tangential magnetized magnetic steel (2b, 3b) is a₂Respectively satisfy: 1.4 x n₁＜a₁＜1.6*n₁，0.9*n₁＜a₂＜1.1*n₁。

7. The magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor according to any one of claims 1 to 3, characterized in that: the rotor (6) is divided into N sections along the axial direction, and the angle is staggered between each two sections of rotors

8. the magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor according to claim 7, characterized in that: the stator (5) is in the form of a fractional slot concentrated coil.

9. The magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor according to claim 7, characterized in that: and the winding of the stator (5) adopts a flat copper wire.

Technical Field

The invention relates to the field of motors, in particular to a built-in permanent magnet motor with a double-layer magnetic steel structure.

Background

The alternating-direct axis inductance of the surface-mounted permanent magnet motor and the built-in permanent magnet motor is not equal, the motor has larger reluctance torque, and the weak magnetic performance is better. However, the magnetic steel is arranged in the motor, the magnetic leakage of a motor rotor is increased, the air gap magnetic density is lower, and the torque/power density of the motor is reduced; in order to further improve the torque density of the interior permanent magnet motor, the d-axis inductance can be reduced, the d-axis and q-axis inductance difference can be increased, the reluctance torque can be improved, and the torque/power density of the motor can be increased by arranging the multilayer magnetic steel on the d-axis.

Compared with a conventional single-layer built-in permanent magnet synchronous motor, the multi-layer magnetic steel built-in permanent magnet motor has larger d and q axis inductance difference, so that the reluctance torque utilization rate is higher, and the torque density is higher. But because the number of layers of the magnetic steel is large, the d-axis inductance is small, the weak magnetic capacity of the motor is reduced, and the wide-speed running range of the motor is reduced. Meanwhile, due to the arrangement of the magnetic barrier, the mechanical strength of the motor rotor is generally reduced.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the prior art, the magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor is provided, so that the mechanical strength of a motor rotor can be ensured, and the motor cannot generate larger magnetic leakage.

The technical scheme is as follows: a magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor comprises a stator and a rotor; the rotor comprises a rotor core, magnetic steel grooves are uniformly distributed in the rotor core along the circumference, the magnetic steel grooves are double-layer U-shaped grooves, and the opening direction of the double-layer U-shaped grooves faces one side of the rotor; two pieces of radial magnetized magnetic steel are distributed in the centers of the magnetic poles of the flat bottom parts of the inner layer and the outer layer of the double-layer U-shaped groove, two pieces of tangential magnetized magnetic steel are respectively arranged at the two side parts of the inner layer and the outer layer of the double-layer U-shaped groove, a magnetic bridge is arranged between the two pieces of radial magnetized magnetic steel, and a magnetic bridge is respectively arranged between the radial magnetized magnetic steel and the tangential magnetized magnetic steel; defining the arc angle of the outer layer magnetic steel as the first arc angle theta₁The arc angle of the inner layer magnetic steel is the second arc angle theta₂Wherein the first polar arc angle θ₁Satisfies the following conditions: 0.6 tau < theta₁< 0.8 × τ, second arc angle θ₂Satisfies the following conditions: 0.4 tau < theta₂＜0.And 6, wherein tau is 180 DEG/p, and p is the pole number of the motor.

Further, the outer diameter d of the rotor₁And inner diameter d₂Satisfies the following conditions: 0.65 × d₁＜d₂＜0.8*d₁The width of a magnetic bridge between two pieces of radial magnetized magnetic steel in the inner layer magnetic steel is m₁The width of the magnetic bridge between the radial magnetized magnetic steel and the tangential magnetized magnetic steel is n₁Wherein m is₁Satisfies the following conditions: 0.003 × d₁＜m₁＜0.004*d₁，n₁Satisfies the following conditions: 0.0025 × d₁＜n₁＜0.0035*d₁(ii) a The width of a magnetic bridge between two pieces of radial magnetized magnetic steel in the outer layer magnetic steel is m₂The width of the magnetic bridge between the radial magnetized magnetic steel and the tangential magnetized magnetic steel is n₂Wherein m is₂Satisfies the following conditions: 0.003 × d₁＜m₂＜0.004*d₁，n₂Satisfies the following conditions: 0.0025 × d₁＜n₂＜0.0035*d₁。

Further, m is satisfied₁＜m₂And n is₁＜n₂。

Furthermore, the distance between the tangentially magnetized magnetic steel in the outer layer magnetic steel and the excircle of the rotor is L₁The distance between the tangentially magnetized magnetic steel in the inner layer magnetic steel and the outer circle of the rotor is L₂Wherein L is₁Satisfies the following conditions: 0.75 × g < L₁＜0.95*g，L₂Satisfies the following conditions: 0.7 × g < L₂< 0.9 × g, g being the thickness of the air gap between the stator and the rotor.

Further, L is satisfied₁＞L₂。

Furthermore, a protruding structure for fixing the position of the magnetic steel is arranged in the magnetic steel groove, wherein the depth of the protruding structure on the radial magnetic steel groove for accommodating the radially magnetized magnetic steel is a₁The depth of the convex structure on the tangential magnetic steel groove for containing the tangential magnetized magnetic steel is a₂Respectively satisfy: 1.4 x n₁＜a₁＜1.6*n₁，0.9*n₁＜a₂＜1.1*n₁。

Further, the rotor is divided into N sections along the axial direction, and each section of the rotor is provided with a rotorAre staggered by an angleWherein 2 is more than N and less than 6,

further, the stator is in the form of a fractional slot concentrated coil.

Further, the winding of the stator adopts flat copper wires.

Has the advantages that: the invention discloses a magnetic steel built-in type double-U-shaped fractional slot concentrated winding permanent magnet motor. Every group of the inner layer magnetic steel and the outer layer magnetic steel under each pole comprises 4 pieces of magnetic steel, and according to the magnetizing direction of the magnetic steel, 2 pieces of magnetic steel 2a with large volume are placed radially, and 2 pieces of magnetic steel 2b with small volume are placed tangentially. The magnetic bridge is arranged between two adjacent magnetic steels in the two groups of magnetic steels, the mechanical strength of the motor rotor can be increased through the magnetic bridge, and meanwhile the flux weakening capability of the motor can be improved. The proper width of the magnetic bridge can ensure the mechanical strength of the motor rotor and prevent the motor from generating larger magnetic leakage.

No matter the width of the magnetic bridge between the magnetic steels or the width of the magnetic bridge between the magnetic steels and the excircle of the rotor, the width of the outer magnetic bridge is larger than that of the inner magnetic bridge. The invention increases the reluctance torque of the motor by increasing the number of layers of the built-in magnetic steel, reduces the pulsation torque and the eddy current loss of the motor by utilizing a segmented rotor mode, improves the operation efficiency and the torque control precision of the motor, and improves the operation efficiency and the torque control precision of the motor.

Drawings

FIG. 1 is a structural schematic diagram of a magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor;

FIG. 2 is a specific structural dimensional constraint of a rotor;

FIG. 3 is a schematic view of a segmented rotor structure.

Detailed Description

The invention is further explained below with reference to the drawings.

As shown in fig. 1 to 3, a magnetic steel built-in double U-shaped fractional slot concentrated winding permanent magnet motor includes a stator 5 and a rotor 6. The stator comprises a stator core 5a and a centralized winding 5b, and the stator core 5a is formed by laminating stator magnetic conducting punching sheets. Rotor 6 includes rotor core 1, and 1 inside magnetic steel grooves 4 that distribute along the circumference evenly of rotor core, magnetic steel grooves 4 are double-deck U type groove, and the opening direction in double-deck U type groove is towards rotor 6 one side. Two pieces of radial magnetized magnetic steel 2a, 3a are distributed in the center of the flat bottom magnetic poles of the inner layer and the outer layer of the double-layer U-shaped groove; two tangential magnetized magnetic steels 2b and 3b are respectively arranged at the two side parts of the inner layer and the outer layer of the double-layer U-shaped groove. A magnetic bridge is arranged between the two pieces of radial magnetized magnetic steel 2a and 3a, and magnetic bridges are respectively arranged between the radial magnetized magnetic steel 2a and 3a and the tangential magnetized magnetic steel 2b and 3 b. The radial magnetized magnetic steel 2a and the tangential magnetized magnetic steel 2b form an inner layer magnetic steel 2, the radial magnetized magnetic steel 3a and the tangential magnetized magnetic steel 3b form an outer layer magnetic steel 3, and the angle of the polar arc occupied by the outer layer magnetic steel 3 is defined as a first polar arc angle theta₁The arc angle of the inner layer magnetic steel 2 is the second arc angle theta₂Wherein the first pole arc angle theta₁Satisfies the following conditions: 0.6 tau < theta₁< 0.8 × τ, second arc angle θ₂Satisfies the following conditions: 0.4 tau < theta₂< 0.6 x τ, where τ is 180 °/p, and p is the number of motor poles.

The magnetic steel groove 4 adopts a double-U-shaped design, so that sufficient magnetic steel arrangement positions can be ensured, and the reluctance torque of the motor can be effectively utilized. By setting a suitable first pole arc angle theta₁And a second arc angle theta₂The motor has optimal d-axis and q-axis inductances, the reluctance torque of the motor is increased, the torque density of the motor is improved, and the fluctuation of the output torque of the motor can be effectively reduced.

Outer diameter d of rotor 6₁And inner diameter d₂Satisfies the following conditions: 0.65 × d₁＜d₂＜0.8*d₁. The relation of the inner diameter and the outer diameter of the motor rotor is set to be suitable, the position of sufficient magnetic steel arrangement in the rotor can be guaranteed, and meanwhile the weight of the motor rotor can be reduced as far as possible. The magnetic bridge width between two radial magnetized magnetic steels 2a in the inner layer magnetic steel 2Degree is m₁The width of the magnetic bridge between the radial magnetized magnetic steel 2a and the tangential magnetized magnetic steel 2b is n₁(ii) a Wherein m is₁Satisfies the following conditions: 0.003 × d₁＜m₁＜0.004*d₁，n₁Satisfies the following conditions: 0.0025 × d₁＜n₁＜0.0035*d₁. The width of a magnetic bridge between two radial magnetized magnetic steels 3a in the outer layer magnetic steel 3 is m₂The width of the magnetic bridge between the radial magnetized magnetic steel 3a and the tangential magnetized magnetic steel 3b is n₂(ii) a Wherein m is₂Satisfies the following conditions: 0.003 × d₁＜m₂＜0.004*d₁，n₂Satisfies the following conditions: 0.0025 × d₁＜n₂＜0.0035*d₁. A magnetic bridge is arranged between the magnetic steels to ensure the mechanical strength of the motor rotor. However, the magnetic bridge causes magnetic leakage of a magnetic field generated by the magnetic steel, which affects the output torque of the motor and the performance of the motor, so that the magnetic bridge is required to be as small as possible. A suitable thickness of the magnetic bridge is very important in order to ensure a reliable mechanical strength and as little magnetic flux leakage as possible.

Since the stress applied to the outer layer magnetic bridges is greater than the stress applied to the inner layer magnetic bridges when the motor rotates, the inner layer magnetic bridges are thinner than the outer layer magnetic bridges, preferably m, in order to minimize magnetic flux leakage₁＜m₂And n is₁＜n₂。

The distance between the tangential magnetized magnetic steel 3b in the outer layer magnetic steel 3 and the excircle of the rotor is L₁The distance between the tangential magnetized magnetic steel 2b in the inner layer magnetic steel 2 and the excircle of the rotor is L₂(ii) a Wherein L is₁Satisfies the following conditions: 0.75 × g < L₁＜0.95*g，L₂Satisfies the following conditions: 0.7 × g < L₂< 0.9 × g, g being the thickness of the air gap between the stator 5 and the rotor 6. Proper value is also set through the magnetic bridge between the magnetic steel and the excircle of the rotor, so that the mechanical strength is ensured, less magnetic leakage is caused, and the optimal L requirement is met₁＞L₂。

In order to fix the position of the magnetic steel, a convex structure is arranged in the magnetic steel groove 4 to fix the position of the magnetic steel. Wherein the depth of the convex structure on the radial magnetic steel groove 4a of the magnetic steel 2a, 3a for accommodating radial magnetization is a₁The tangential magnet steel groove 4b for accommodating the tangentially magnetized magnet steels 2b and 3b is convexDepth of structure a₂Respectively satisfy: 1.4 x n₁＜a₁＜1.6*n₁，0.9*n₁＜a₂＜1.1*n₁. The arrangement of the protruding structure can limit the play of the magnetic steel, if the magnetic steel plays in a magnetic steel groove when the motor runs, the motor generates abnormal noise or vibration, the torque pulsation of the motor can be increased, and even the magnetic steel is damaged due to play to cause motor failure.

The rotor 6 adopts a segmented structure and is divided into N segments along the axial direction, and the angle is staggered between each two segments of rotors

Wherein 2 is more than N and less than 6,

the rotor is staggered in sections by an angle, so that the cogging torque of the motor can be reduced, the fluctuation of the output torque of the motor is reduced, and the performance of the motor is improved.

The stator 5 is a fractional groove concentrated winding form, such as a 12-groove 10-pole structure, and a fractional groove concentrated winding structure is adopted, so that the cogging torque of the motor is small, the torque fluctuation can be reduced, the end part of the motor is small, the copper loss is small, and the efficiency is high. The winding of stator 5 adopts flat copper wire, and flat copper wire can reduce motor copper loss by a wide margin and improve motor efficiency, and special distributed winding can reduce the electric current harmonic simultaneously, reduces motor alternating current loss.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.