CN218335475U

CN218335475U - Built-in asymmetric pole arc angle U-shaped permanent magnet rotor

Info

Publication number: CN218335475U
Application number: CN202222724329.5U
Authority: CN
Inventors: 林德芳; 罗锦英; 王明光
Original assignee: Shanghai Top Motor Co ltd
Current assignee: Shanghai Top Motor Co ltd
Priority date: 2022-10-17
Filing date: 2022-10-17
Publication date: 2023-01-17
Anticipated expiration: 2032-10-17

Abstract

A built-in asymmetric pole arc angle U-shaped permanent magnet rotor relates to the technical field of motors and comprises a rotor core, wherein a plurality of permanent magnet units are arranged on the rotor core, and the permanent magnet units are symmetrically distributed around the axis of the rotor core; the permanent magnet unit consists of a first magnetic steel, a second magnetic steel and a third magnetic steel, the first magnetic steel is arranged on the anticlockwise side of the d shaft, the second magnetic steel is arranged on the clockwise side of the d shaft, the first magnetic steel and the second magnetic steel are arranged in a splayed shape with inward narrow openings, and the third magnetic steel is arranged on the splayed narrow opening part; the included angle between the first magnetic steel and the third magnetic steel is alpha 1, the included angle between the second magnetic steel and the third magnetic steel is alpha 2, alpha 1 is larger than alpha 2, and the inner end and the outer end of the first magnetic steel and the inner end and the outer end of the second magnetic steel are both provided with magnetism isolating grooves. The utility model provides a rotor can effectively reduce the torque ripple.

Description

Built-in asymmetric pole arc angle U-shaped permanent magnet rotor

Technical Field

The utility model relates to a motor technology especially relates to a technique of built-in asymmetric utmost point arc angle U type permanent magnet rotor.

Background

In the aspect of the permanent magnet synchronous motor which is currently suitable for the electric automobile, the defects of large torque fluctuation, low power density, narrow high-speed constant power range, low overload capacity, poor reliability and the like exist, and the requirements are difficult to meet.

Reducing motor torque ripple is one of the major concerns in motor research. The stator iron core and the permanent magnet interact to generate positioning torque, and the current and counter potential are non-sinusoidal, so that harmonic torque is generated in the operation of the motor. The cogging torque is also called the reluctance torque, which is a fatal defect in a speed regulating system in an automatic occasion and a mechatronic occasion. When the motor is in operation and the frequency of the torque coincides with the mechanical resonance frequency of the stator or rotor, the vibration and noise generated by the cogging torque are significantly amplified, and also affect the low-speed performance and the positioning accuracy.

SUMMERY OF THE UTILITY MODEL

To the defect that exists among the above-mentioned prior art, the utility model aims to solve the technical problem that a can reduce undulant built-in asymmetric utmost point arc angle U type permanent magnet rotor of motor torque is provided.

In order to solve the technical problem, the utility model provides a built-in asymmetric polar arc angle U-shaped permanent magnet rotor, which comprises a rotor core, wherein a plurality of permanent magnet units are arranged on the rotor core, and each permanent magnet unit is symmetrically arranged around the axis of the rotor core; the method is characterized in that:

the permanent magnet unit consists of a first magnetic steel, a second magnetic steel and a third magnetic steel, the first magnetic steel is arranged on the counterclockwise side of the d axis, the second magnetic steel is arranged on the clockwise side of the d axis, the first magnetic steel and the second magnetic steel are arranged in a splayed shape with inward narrow openings, and the third magnetic steel is arranged on the splayed narrow opening part;

the included angle between the first magnetic steel and the third magnetic steel is alpha 1, the included angle between the second magnetic steel and the third magnetic steel is alpha 2, alpha 1 is larger than alpha 2, and the inner end and the outer end of the first magnetic steel and the inner end and the outer end of the second magnetic steel are both provided with magnetism isolating grooves.

Furthermore, the structure of the magnetism isolating groove at the inner end of the first magnetic steel is different from that of the magnetism isolating groove at the inner end of the second magnetic steel, so that an asymmetric structure is formed.

Furthermore, a circular auxiliary groove is formed in the middle of the permanent magnet unit and is located between the first magnetic steel and the second magnetic steel.

The utility model provides a built-in asymmetric polar arc angle U type permanent magnet rotor, adopt every polar arc angle asymmetric structure, make adjacent magnetic pole central line asymmetric structure, can effectively promote comprehensive properties, motor stator does not need the chute, the rotor does not need the chute, need not set up measures such as inhomogeneous air gap between stator and rotor, just can effectively reduce and reduce the torque fluctuation, improve motor air gap magnetic field waveform, under the condition that does not increase motor groove number, can improve the undulant fundamental wave number of times of tooth's socket torque, reduce tooth's socket fundamental wave and higher harmonic torque amplitude, reduce the torque fluctuation that the tooth's socket arouses, the q axle radial force that makes magnetic pole radial center line's d axle and interelectrode center line tends to balance, improve air gap flux density waveform, reduce mechanical vibration, noise and back emf harmonic, reduce the iron core loss, effectively reduce the torque fluctuation.

Drawings

Fig. 1 is a schematic radial cross-sectional view of a built-in asymmetric pole arc angle U-shaped permanent magnet rotor according to an embodiment of the present invention;

fig. 2 is a torque fluctuation histogram of the built-in asymmetric pole arc angle U-shaped permanent magnet rotor and the existing built-in V-shaped permanent magnet rotor according to the embodiment of the present invention.

Detailed Description

The following description is provided for the embodiments of the present invention, but the present invention is not limited to the embodiments, and all the similar structures and similar variations of the present invention can be adopted to fall into the protection scope of the present invention.

As shown in fig. 1, an embodiment of the present invention provides a built-in asymmetric pole arc angle U-shaped permanent magnet rotor, which includes a rotor core 1, wherein the rotor core 1 is provided with a plurality of permanent magnet units, and each permanent magnet unit is symmetrically arranged around the axis of the rotor core;

the permanent magnet unit consists of a first magnetic steel 21, a second magnetic steel 22 and a third magnetic steel 23, the first magnetic steel 21 is arranged on the anticlockwise side of the d axis, the second magnetic steel 22 is arranged on the clockwise side of the d axis, the first magnetic steel 21 and the second magnetic steel 22 are arranged in a splayed shape with inward narrow openings, and the third magnetic steel 23 is arranged on the splayed narrow opening part;

the included angle between the first magnetic steel 21 and the third magnetic steel 23 is alpha 1, the included angle between the second magnetic steel 22 and the third magnetic steel 23 is alpha 2, alpha 1 is larger than alpha 2, the inner end and the outer end of the first magnetic steel 21 are respectively provided with a

magnetism isolating groove

51 and 52, the inner end and the outer end of the second magnetic steel 22 are respectively provided with a

magnetism isolating groove

53 and 54, alpha 1 is larger than alpha 2, so that the arc angle of each pole is asymmetric, the q axis and the q ' axis of the adjacent magnetic poles are asymmetric, and the deviation beta angle between the q axis and the q ' axis is beta (the q axis in figure 1 is the magnetic pole center line of the permanent magnet unit at the anticlockwise side, and the q ' axis is the magnetic pole center line of the permanent magnet unit at the clockwise side);

the magnetic isolation groove 52 at the inner end of the first magnetic steel 21 and the magnetic isolation groove 53 at the inner end of the second magnetic steel 22 are different in structure, and an asymmetric structure is formed.

The embodiment of the utility model provides an in, the middle part of permanent magnetism unit is equipped with circular shape auxiliary tank 4, and auxiliary tank 4 is located between first magnet steel 21, the second magnet steel 22, sets up the auxiliary tank and can reduce the iron core loss, improves the air gap magnetic field waveform, reduces the torque fluctuation, suppresses static and dynamic armature reaction demagnetization.

Fig. 2 is a torque fluctuation histogram of the embodiment of the present invention and the existing built-in V-shaped permanent magnet rotor, the vertical axis Tr in fig. 2 is torque fluctuation, the square column a is torque fluctuation of the existing built-in V-shaped permanent magnet rotor, and the square column E is torque fluctuation of the present embodiment.

The torque fluctuation caused by the electromagnetic reason can generate mechanical and electromagnetic noises, and influences the stable operation and reliability of the motor, and the torque fluctuation is divided into two types: one is cogging torque, i.e. torque generated by interaction of stator cogging and rotor permanent magnets, which fluctuates with periodic variation in spatial position, and is independent of stator current; the other is ripple torque, i.e., harmonic torque caused by differences in current and back emf waveforms. The torque ripple of the permanent magnet synchronous motor for the vehicle is the superposition of a cogging torque and a ripple torque.

As can be seen from fig. 2: the torque fluctuation of the existing built-in V-shaped permanent magnet rotor is 73%, the torque fluctuation of the embodiment is 47.5%, and the torque fluctuation is obviously reduced, so that the rotor of the embodiment can effectively reduce the cogging torque fluctuation and the ripple torque fluctuation.

The motor adopting the permanent magnet rotor of the embodiment is compared with the motor adopting the existing built-in V-shaped permanent magnet rotor with the same specification, and the parameters of the motor are as follows: the rated power is 18KW, the rated rotating speed is 3000r/min, the maximum rotating speed is 9000r/min, the rated torque is 57.3Nm, and the maximum torque is 126Nm;

the cogging torque of the motor adopting the existing built-in V-shaped permanent magnet rotor is 2.63Nm, the cogging torque fluctuation is 4.58 percent, and the efficiency is 94 percent;

the cogging torque of the motor adopting the permanent magnet rotor of the embodiment is 1.30Nm, the cogging torque fluctuation is 2.27%, and the efficiency is 94%;

therefore, by adopting the motor with the same specification, the cogging torque fluctuation is obviously reduced, and the efficiency is obviously improved.

The embodiment of the utility model provides a constitute adjacent magnetic pole central line asymmetric structure, can effectively promote the comprehensive properties. The motor stator does not need a chute, the rotor does not need a skewed pole, measures such as uneven air gaps do not need to be arranged between the stator and the rotor, torque fluctuation can be effectively reduced, the waveform of an air gap magnetic field of the motor is improved, the fundamental wave frequency (frequency) of the cogging torque fluctuation can be improved under the condition that the number of slots of the motor is not increased, the torque amplitude of the cogging fundamental wave and the high harmonic wave is reduced, torque fluctuation caused by the cogging is reduced, the radial force of a d shaft of a radial central line of a magnetic pole and a q shaft of a central line of interelectrodes tends to be balanced, the waveform of the air gap magnetic flux density is improved, mechanical vibration, noise and back electromotive force harmonic waves are reduced, iron core loss is reduced, torque fluctuation is effectively reduced, overload capacity is improved, the driving requirement of an electric automobile is met, and the characteristics of the motor such as high power density, low noise, low torque fluctuation, wide speed regulation, small-size and light weight, stable operation are realized.

Claims

1. A built-in asymmetric pole arc angle U-shaped permanent magnet rotor comprises a rotor core, wherein a plurality of permanent magnet units are arranged on the rotor core, and the permanent magnet units are symmetrically distributed around the axis of the rotor core; the method is characterized in that:

the permanent magnet unit consists of a first magnetic steel, a second magnetic steel and a third magnetic steel, the first magnetic steel is arranged on the anticlockwise side of the d shaft, the second magnetic steel is arranged on the clockwise side of the d shaft, the first magnetic steel and the second magnetic steel are arranged in a splayed shape with inward narrow openings, and the third magnetic steel is arranged on the splayed narrow opening part;

2. The built-in asymmetric pole arc angle U-shaped permanent magnet rotor of claim 1, characterized in that: the magnetic isolation groove at the inner end of the first magnetic steel is different from the magnetic isolation groove at the inner end of the second magnetic steel in structure, so that an asymmetric structure is formed.

3. The built-in asymmetric pole arc angle U-shaped permanent magnet rotor of claim 1, characterized in that: and the middle part of the permanent magnet unit is provided with a circular auxiliary groove, and the auxiliary groove is positioned between the first magnetic steel and the second magnetic steel.