CN105680580B - Stator and motor having the same - Google Patents

Abstract

The invention discloses a stator and a motor with the same, wherein the stator is arranged in the motor and subjected to edge cutting, the number of slots of each pole of the stator in each phase is less than 5, the number of poles of the motor is less than or equal to 12, and the number of the edge cutting of the stator is not equal to the number of the poles of the motor. The stator and the motor with the same effectively solve the problems that after trimming processing of the stator of the motor in the prior art, the flux linkage of the motor is asymmetric, three-phase current is unbalanced when the motor operates, torque fluctuation of the motor is increased, and the motor cannot normally and stably operate.

Description

Stator and motor having the same

technical field

The present invention relates to the technical field of motors, and in particular, to a stator and a motor having the same.

Background technique

In the prior art, the motor of the compressor usually trims the stator to ensure the circulation area of the refrigerant and the circulating flow of the lubricating oil. After the stator is trimmed, the waste of silicon steel sheet materials during stamping can be reduced, and the weight of the motor can be reduced to facilitate the assembly and transportation of the compressor. When designing the structure of the stator trimming, it is usually to ensure the circulation area of the compressor refrigerant without considering other influences, resulting in asymmetrical flux linkage of the motor, unbalanced three-phase current when the motor is running, and increased motor torque fluctuations. If it is too large, the motor cannot run normally and stably.

SUMMARY OF THE INVENTION

In the embodiment of the present invention, a stator and a motor having the same are provided, so as to solve the problem of asymmetric flux linkage of the motor caused by the stator of the motor in the prior art after edge trimming, unbalanced three-phase current when the motor is running, and motor torque If the fluctuation increases, the motor cannot run normally and stably.

In order to achieve the above purpose, the present invention provides a stator for being installed in a motor, the stator is processed by trimming, the number of slots per pole and phase of the stator is less than 5, the number of poles of the motor is less than or equal to 12, and the trimming of the stator is The number is not equal to the number of poles of the motor.

Further, the relationship between the number of trimmed sides of the stator and the number of poles of the motor is not divisible by each other.

Further, the number of trimmed sides of the stator is greater than the number of poles of the motor.

Further, the number of poles of the motor is 4, and the number of trimmed edges is 6 or 10.

Further, the cut edges of the stator are arranged symmetrically in pairs.

Further, the cut edge of the stator and the phase belt of any phase in the motor are arranged in a dislocation.

圆心角的取值范围为：Further, the corresponding central angle of the cut edge of the stator in the cross section of the stator is

The range of values for the central angle is:

其中，θ为一对极内任一相相带所占的机械角度。

where θ is the mechanical angle occupied by any phase band within a pair of poles.

Further, the cutting depth of the cutting edge of the stator is D, and the value range of the cutting depth D is: D≤H/2, where H is the width of the stator yoke.

Further, the contact area between the stator and the housing of the motor is A, and the total area of the outer peripheral surface of the stator is B, where A≥0.7B.

According to another aspect of the present invention, there is provided a motor comprising the above stator.

In a motor with less than 5 slots per pole per phase (number of poles ≤ 12), the number of trimmed sides of the stator and the number of pole pairs should not be equal, so that the combined magnetic potential rotation in each electrical cycle will not appear at the same time on the trimmed side. At the same time, it will not be located at the cutting edge, so that the asymmetry of the magnetic circuit of the motor will not be triggered, and the three-phase current of the motor will be balanced when the motor is running, the flux linkage of the motor will be symmetrical, and the torque ripple will be reduced, so that the motor can run normally and stably.

Description of drawings

1 is a schematic diagram of the distribution of magnetic lines of force of a stator in the prior art;

Fig. 2 is the schematic diagram of the flux linkage calculation value of the stator in the prior art;

3 is a schematic diagram of the distribution of magnetic lines of force of the stator according to an embodiment of the present invention;

Fig. 4 is the schematic diagram of the flux linkage calculation value of the stator according to the embodiment of the present invention;

Figure 5 is a comparison diagram of the torque ripple caused by the stator after edge trimming;

Figure 6 is a comparison diagram of the magnetic density change caused by the stator after edge trimming;

7 is a schematic structural diagram of a stator according to an embodiment of the present invention;

FIG. 8 is a comparison diagram of the holding force of the trimmed edge of the stator.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments, but it is not intended to limit the present invention.

Referring to FIG. 3 , according to an embodiment of the present invention, a stator is provided for installation in a motor, the stator is processed by trimming, the number of slots per pole per phase of the stator is less than 5, and the number of poles of the motor is less than or equal to 12. The number of trimmed sides of the stator is not equal to the number of poles of the motor.

In a motor with less than 5 slots per pole per phase (number of poles ≤ 12), the number of trimmed sides of the stator and the number of pole pairs should not be equal, so that the combined magnetic potential rotation in each electrical cycle will not appear at the same time on the trimmed side. At the same time, it will not be located at the cutting edge, so that the asymmetry of the magnetic circuit of the motor will not be triggered, and the three-phase current of the motor will be balanced when the motor is running, the flux linkage of the motor will be symmetrical, and the torque ripple will be reduced, so that the motor can run normally and stably.

FIG. 1 shows a stator structure with the same number of cut sides as the number of motor poles in the prior art. The motor is a 36-slot 4-pole motor, and the number of cut sides 20 of the stator 10 is 4, which can be seen from FIG. 1 . The distribution of the magnetic field lines of the out-cut edge, when the combined magnetic potential rotation in each electrical cycle is located at the edge of the edge or not at the edge of the edge at the same time, it can be seen from the calculated value of the flux linkage in Figure 2 that the flux linkage is asymmetrical. The phase current is unbalanced, the torque fluctuation of the motor increases, the second harmonic appears, and the motor cannot run normally and stably, as shown in Figure 5.

Fig. 3 shows the 36-slot 4-pole motor of this embodiment, and the number of trimmings is 6. When the trimming number of the 36-slot 4-pole motor is 6, the distribution of the magnetic field lines of the trimming is shown in Fig. 3, and Fig. 4 shows the It can be seen from the calculated value of the flux linkage that the flux linkage of the motor is symmetrical, as shown in Table 1, and it can be seen in combination with Fig. 4 that when the number of trimmed sides of the stator 10 is equal to the number of poles of the motor, the flux linkage value is asymmetric and rotates. The torque ripple is the largest; when the number of trimmed sides of the stator is not equal to the number of poles of the motor, the flux linkage value is symmetrical and the torque ripple is reduced.

Further preferably, the relationship between the number of trimmed sides of the stator and the number of poles of the motor is not divisible by each other. That is to say, the number of trimmed sides of the stator is not divisible by the number of poles of the motor, and the number of poles of the motor cannot be divisible by the number of trimmed sides of the stator. For example, when the number of poles of the motor is 12, the number of trimmed sides of the stator cannot be 2, 4, 6, 12, etc. In order to ensure the normal and stable operation of the motor, it is further preferred that the number of trimmed sides of the stator is greater than the number of poles of the motor. The number of trimmed edges can be 7, 8, 9, etc.

The number of poles of the motor is 4 and the number of trimmed edges is 6 or 10. In the case where the number of trimmed sides of the stator and the number of poles of the motor are not divisible by each other, the torque ripple will be further reduced. The relationship is not divisible by each other, and the torque ripple is small at this time. When the number of trims is 8, the relationship between the number of trims and the series is mutually divisible. In this structure, the flux linkage value is asymmetric, and the torque ripple is 6 or 10 relative to the number of trims. bigger.

When trimming the stator, symmetrical trimming is performed, so that the trimmings 20 of the stator 10 are symmetrically arranged in pairs. Such symmetrical cut edges 20 can better reduce torque ripple.

The cut edge 20 of the stator 10 is arranged in a misalignment with the phase belt of any phase in the motor. As shown in Figure 7, the selection of the length L dimension of the cross section of the trimming should consider the distribution of the winding phase belts, and the phase belts of any phase of the motor should be dislocated from the trimming range to avoid a single phase in the motor phase belts always aligning Edge trim position.

圆心角的取值范围为：The central angle corresponding to the cut edge 20 of the stator 10 in the cross section of the stator is

The range of values for the central angle is:

其中，θ为一对极内任一相相带所占的机械角度。

where θ is the mechanical angle occupied by any phase band within a pair of poles.

In the 36-slot 4-pole motor shown in Figure 1, the four trimmings only affect the magnetic circuit of the B/C two-phase, the reluctance of the B/C two-phase increases, and the flux linkage value is smaller than the A-phase. On the contrary, referring to the present embodiment of Fig. 3, the effect of edge trimming on the flux linkage of A/B/C phase is alternate, and the effect of edge trimming on A/B/C three-phase flux linkage in one cycle of electromagnetic field rotation is Consistent, so the values of the three-phase flux linkages are equal.

The cutting depth of the cutting edge of the stator is D, and the value range of the cutting depth D is: D≤H/2, where H is the width of the stator yoke. Considering the magnetic density distribution of the thin yoke of the motor, in order not to cause the sharp fluctuation of the magnetic density at the cutting edge when the motor rotates, Fig. 6 shows the magnetic density distribution of the thin yoke of the motor, in order to avoid the cutting The sharp fluctuation of the magnetic density at the edge, and combined with Figure 7, the value range of D in the deepest part of the cut edge: D≦H/2. The deeper the cutting edge is, the greater the magnetic density at the cutting edge will be until saturation. When the motor rotates, the magnetic density at the cutting edge will change greatly, and the reluctance torque will change drastically, resulting in an increase in torque fluctuation. The cutting form of the cutting edge here is not limited to the straight cutting edge, but also includes the cutting edge of other shapes. The above-mentioned cutting depth refers to the distance between the closest point of the cutting edge near the bottom of the slot and the radius of the stator.

The contact area between the stator and the housing of the motor is A, and the total area of the outer peripheral surface of the stator is B, where A≥0.7B. Considering that the interference between the stator and the shell tends to deviate downward, the product of the tangential force and the friction coefficient generated by the motor during operation is greater than the holding force between the mating objects, which will cause the radial sliding of the motor. In order to ensure the normal output of the motor torque, the ratio of the contact area between the stator and the housing of the motor to the total area of the outer peripheral surface of the stator should not be less than 0.7. As shown in Fig. 8, when the ratio of A/B is higher than 0.7, the reduction of partial contact and full contact holding force is smaller.

The present invention also provides a motor including the stator of the above embodiment. In a motor with less than 5 slots per pole per phase (number of poles ≤ 12), the number of trimmed sides of the stator and the number of pole pairs should not be equal, so that the combined magnetic potential rotation in each electrical cycle will not appear at the same time on the trimmed side. At the same time, it will not be located at the cutting edge, so that the asymmetry of the magnetic circuit of the motor will not be triggered, and the three-phase current of the motor will be balanced when the motor is running, the flux linkage of the motor will be symmetrical, and the torque ripple will be reduced, so that the motor can run normally and stably.

Of course, the above are preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the basic principle of the present invention, several improvements and modifications can also be made, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims (8)

1. The stator is used for being installed in a motor and subjected to edge cutting treatment and is characterized in that the number of slots of each phase of each pole of the stator is less than 5, the number of poles of the motor is less than or equal to 12, the number of the cut edges of the stator is not equal to the number of the poles of the motor, the cut edges of the stator and the phase belts of any phase of the motor are arranged in a staggered mode, and the relation between the number of the cut edges of the stator and the number of the poles of the motor is not divided completely.

2. The stator of claim 1 wherein the number of cut edges of the stator is greater than the number of poles of the motor.

3. The stator as claimed in claim 1, wherein the number of poles of the motor is 4 and the number of the cut edges is 6 or 10.

4. A stator according to claim 3, wherein the cutting edges of the stator are arranged symmetrically in pairs.

5. The stator of claim 1, wherein the corresponding central angle of the cut edge of the stator in the cross section of the stator is

The value range of the central angle is as follows:

wherein θ is the mechanical angle occupied by any phase band in a pair of poles.

6. The stator according to claim 1, wherein the cutting depth of the cutting edge of the stator is D, and the cutting depth D has a range of values: d is less than or equal to H/2, wherein H is the width of the stator yoke.

7. The stator according to claim 1, wherein the stator has a contact area A with a housing of the motor and a total area of an outer circumferential surface of the stator is B, wherein A ≧ 0.7B.

8. An electrical machine comprising a stator according to any one of claims 1 to 7.

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