阅读说明：本技术 用于永磁电机的定子及永磁电机 (Stator for permanent magnet motor and permanent magnet motor ) 是由 刘新俊 李明哲 于 2018-06-06 设计创作，主要内容包括：本发明涉及一种用于永磁电机的定子及永磁电机。该定子包括筒状的磁轭以及沿径向从该磁轭朝向该永磁电机的转子延伸的多个定子齿,在多个定子齿朝向转子的端面上设有沿周向相互间隔的多个凹槽。本发明的定子及永磁电机能够降低电机的磁钢涡流损耗,提高电机的效率,同时降低永磁体发生不可逆退磁的风险。(The invention relates to a stator for a permanent magnet motor and the permanent magnet motor. The stator comprises a cylindrical magnet yoke and a plurality of stator teeth extending from the magnet yoke towards the rotor of the permanent magnet motor along the radial direction, and a plurality of grooves which are mutually spaced along the circumferential direction are arranged on the end faces of the plurality of stator teeth towards the rotor. The stator and the permanent magnet motor can reduce the eddy current loss of the magnetic steel of the motor, improve the efficiency of the motor and reduce the risk of irreversible demagnetization of the permanent magnet.)

1. a stator (1) for a permanent magnet electrical machine, comprising:

A cylindrical yoke (2), and

A plurality of stator teeth (4) extending from the inner surface of the yoke (2) towards the centre of the rotor (3) of the permanent magnet machine,

It is characterized in that the preparation method is characterized in that,

The end face, facing the rotor (3), of the stator teeth (4) is provided with a plurality of grooves (5) which are spaced from each other along the circumferential direction.

2. Stator (1) according to claim 1, characterized in that the grooves (5) are evenly distributed in the circumferential direction.

3. A stator (1) according to claim 1, characterized in that each groove (5) is of the same size and shape in radial cross section.

4. A stator (1) according to claim 3, characterized in that the width of each groove (5) in the circumferential direction is equal to the spacing between two adjacent grooves (5) in the circumferential direction.

5. stator (1) according to claim 1, characterized in that each stator tooth (4) has a stator tooth shoe (6) widening in the circumferential direction on the end face facing the rotor (3), the grooves being provided on the stator tooth shoes (6), the depth of each groove (5) in the radial direction being not greater than the minimum width of the stator tooth shoe (6) in the radial direction.

6. Stator (1) according to claim 1 or 5, characterized in that a recess (8) narrowing in the circumferential direction is provided on the side of the stator teeth (4) not facing the rotor (3).

7. a stator (1) according to claim 1, characterized in that the number of grooves (5) is set according to the size of the inner diameter of the stator (1).

8. A stator (1) according to claim 1, characterized in that it is stacked from a plurality of stator laminations formed by stamping, wherein the grooves (5) are stamped at the same time as the stator laminations are stamped and manufactured.

9. A stator (1) according to claim 8, wherein the respective grooves (5) of each stator lamination are axially aligned after stacking to form the stator.

10. A permanent magnet electrical machine comprising a stator (1) according to one of claims 1-9.

Technical Field

the invention relates to the field of permanent magnet motors. In particular, the present invention relates to a stator for a permanent magnet machine and a permanent magnet machine comprising the stator.

Background

The motor is an electromagnetic device for realizing electric energy conversion or transmission according to the electromagnetic induction law, and the motor is mainly used for generating driving torque and serving as a power source of electric appliances or various machines. The permanent magnet synchronous motor adopts a permanent magnet as a rotor, three-phase symmetrical current is introduced into a stator winding to generate a rotating magnetic field, and the rotor moves under the action of electromagnetic force in the rotating magnetic field, so that electric energy is converted into kinetic energy and torque is output. The permanent magnet synchronous motor has the advantages of good torque and rotating speed characteristics, higher efficiency compared with other motors, convenience in control and the like, so that the permanent magnet synchronous motor is mostly adopted by common electric vehicles.

However, when the permanent magnet synchronous motor runs at a high speed, the eddy current loss of the magnetic steel caused by factors such as higher harmonics generated by the current of the stator winding can cause the temperature of the permanent magnet to rise, so that the efficiency of the motor is reduced; meanwhile, when the magnetic field intensity generated by the winding at the permanent magnet is too large or the temperature of the permanent magnet is too high, irreversible demagnetization of the permanent magnet material can be caused, so that the performance of the motor is seriously influenced.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to provide a stator and a permanent magnet synchronous motor which can reduce the risk of demagnetization of permanent magnets in a permanent magnet synchronous motor rotor and improve the motor efficiency.

The above problems are solved by a stator for a permanent magnet synchronous machine according to the present invention. The stator has a cylindrical yoke and a plurality of stator teeth extending from the inner surface of the yoke toward the center of the rotor of the permanent magnet motor, and a plurality of grooves spaced from each other in the circumferential direction are provided on the end surface of the stator teeth toward the rotor. The grooves on the stator teeth can reduce the magnetic flux density of the low-frequency part, so that the magnetic steel eddy current loss of the permanent magnet is reduced, and the efficiency of the motor is improved; meanwhile, the magnetic field intensity of the stator coil generated at the permanent magnet of the rotor is reduced, so that the risk of irreversible demagnetization of the permanent magnet is reduced.

According to a preferred embodiment of the invention, the plurality of grooves of the stator are evenly distributed in the circumferential direction. Preferably, each groove is the same size and shape in radial cross-section. Further preferably, a width of each groove in the circumferential direction is equal to a pitch between adjacent two grooves in the circumferential direction. This configuration makes the stator easier to process.

According to a further preferred embodiment of the invention, a respective stator tooth shoe is formed on the end face of each stator tooth facing the rotor, on which stator tooth shoe a groove according to the invention is provided. Each groove extends radially into the stator tooth to a depth no greater than the minimum width of the stator tooth shoe in the radial direction, thereby avoiding the groove from affecting the structural strength of the stator tooth shoe.

According to a further preferred embodiment of the invention, recesses which narrow in the circumferential direction are provided on the side of the stator teeth which faces away from the rotor. Due to the arrangement of the concave part, local magnetic saturation can be generated on the stator teeth, and higher harmonics are filtered, so that the overall efficiency of the motor is improved.

according to another preferred embodiment of the present invention, the number of the plurality of grooves on the stator is set according to the size of the inner diameter of the stator. For same stator, the more the quantity of recess, the effect that reduces magnet steel eddy current loss and demagnetization risk is just better, and the upper limit of the recess quantity that can set up on the stator mainly by the internal diameter decision of stator. Therefore, it is preferable to provide as many grooves as possible on the stator according to the size of the inner diameter of the stator. According to experiments, the magnetic steel eddy current loss of the permanent magnet is reduced by 8.3% when 1440 grooves are totally arranged on the inner side of the whole stator for the permanent magnet motor with the stator outer diameter of 270mm and the inner diameter of 210 mm.

According to another preferred embodiment of the invention, the stator is formed by stacking a plurality of stator laminations formed by stamping, wherein the grooves according to the invention are stamped and formed simultaneously when the stator laminations are stamped and manufactured. The grooves are formed together when the stator punching sheet is manufactured, so that the manufacturing process of the stator is simplified, and the cost is saved. It is also preferred that after stacking to form the stator, the respective grooves of each stator lamination are axially aligned to form axially through grooves in the stator teeth.

The above problem is solved by a permanent magnet synchronous machine according to the invention, comprising a stator having the above mentioned features.

Drawings

The invention is further described below with reference to the accompanying drawings. Identical reference numbers in the figures denote functionally identical elements. Wherein:

Fig. 1 is a schematic partly sectional view of a permanent magnet synchronous machine according to an embodiment of the invention in a cross section perpendicular to the longitudinal axis; and

Fig. 2 is a partially enlarged view of the permanent magnet synchronous motor shown in fig. 1.

Detailed Description

Referring to fig. 1, a partial cross-sectional view of a permanent magnet synchronous machine according to an embodiment of the invention is shown in a cross-section perpendicular to the longitudinal axis of the machine. As shown in fig. 1, a motor rotor 3 is coaxially fitted in a hollow stator 1, and when the motor is operated, the stator 1 is stationary and the rotor 3 rotates about its central axis with respect to the stator 1. A plurality of permanent magnets 9 are provided on the side of the rotor 3 facing the stator 1. The stator 1 has a cylindrical yoke 2, and a plurality of stator teeth 4 are provided on the inner peripheral side of the yoke 2, each stator tooth 4 extending from the inner peripheral side of the yoke 2 toward the center of the rotor 3 in the radial direction. Stator teeth 6 may be formed on the end portions of the stator teeth 4 facing the rotor 3, and portions of the stator teeth 4 connecting the stator teeth 6 and the yoke 2 may be formed as body portions 7 of the stator teeth 6.

Referring next to fig. 2, therein is shown an enlarged view of a portion of the permanent magnet synchronous machine shown in fig. 1. As shown in fig. 2, a plurality of axially extending grooves 5 are provided on the end face of the stator teeth 4 facing the rotor 3, the grooves 5 being spaced apart from one another in the circumferential direction. The groove 5 can reduce the magnetic flux density of the low-frequency part, thereby reducing the magnetic steel eddy current loss of the permanent magnet and improving the efficiency of the motor. Meanwhile, the magnetic field intensity of the stator coil generated at the permanent magnet of the rotor is reduced, so that the risk of irreversible demagnetization of the permanent magnet is reduced.

The width of each groove 5 in the circumferential direction may be equal to the interval between two adjacent grooves in the circumferential direction. The depth of the groove 5 extending radially into the stator teeth 4 is not greater than the minimum width of the stator tooth shoes 6 in the radial direction to avoid the influence of the groove 5 on the structural strength of the stator tooth shoes 6. Preferably, all the grooves 5 on the stator 1 have the same size and shape, and these grooves 5 are evenly distributed in the circumferential direction of the stator inner diameter formed by the end faces of all the stator teeth 4 facing the rotor 3.

Under the condition that other factors are unchanged, the more the total number of the grooves 5 formed on all the stator teeth 4 of the stator 1 is, the better the effect of reducing the eddy current loss of the magnetic steel is. For example, it is experimentally found that for a permanent magnet motor with an outer diameter of 270mm and an inner diameter of 210mm, when 1440 grooves 5 are provided on the inner side of the entire stator 1, the magnetic steel eddy current loss of the permanent magnet will be reduced by 8.3%. In practical machining operations, the upper limit of the total number of grooves 5 that can be provided inside the stator 1 is mainly determined by the inner diameter of the stator 1, i.e. the distance of the end faces of the stator teeth 4 towards the rotor 3 from the central axis of the stator. Therefore, it is preferable to provide as many grooves 5 as possible in the stator 1 according to the size of the inner diameter of the stator 1.

Furthermore, according to a preferred embodiment of the present invention, a recess 8 may be provided on the main body portion 7 of the stator tooth 4, the main body portion 7 being narrowed at the recess 8 compared to other portions, i.e. the cross-sectional area at the recess 8 is relatively small. The recess 8 may be provided on any one or more side surfaces of the main body portion 7 except for the end surface facing the rotor 3, and the present invention is not limited to a specific position, shape, and number of the recesses 8. The recesses 8 may create local magnetic saturation on the stator teeth 4, filtering higher harmonics, thereby improving the overall efficiency of the motor.

Although possible embodiments have been described by way of example in the above description, it should be understood that numerous embodiment variations exist, still by way of combination of all technical features and embodiments that are known and that are obvious to a person skilled in the art. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. From the foregoing description, one of ordinary skill in the art will more particularly provide a technical guide to convert at least one exemplary embodiment, wherein various changes may be made, particularly in matters of function and structure of the components described, without departing from the scope of the following claims.

reference numerals

1 stator

2 magnetic yoke

3 rotor

4 stator teeth

5 groove

6 stator tooth boots

7 main body part

8 concave part

9 permanent magnet