CN114079341A - Method for weakening target harmonic, low-harmonic winding and axial flux motor - Google Patents

Abstract

The invention discloses a method for weakening target harmonic waves, which comprises the following steps: winding a first set of windings; according to the preset vector included angle of two groups of target harmonics, the number of stator teeth which need to be different between the effective conductors corresponding to the first set of windings and the second set of windings is deduced, the two groups of target harmonics are respectively generated by the first set of windings and the second set of windings, the vector included angle of the two groups of target harmonics is the preset vector included angle, the target effect can be realized, and the target effect comprises: the two groups of target harmonics cancel or weaken each other; and counting the stator teeth of the stator teeth number around the stator iron core by taking the first set of winding as a reference, and then winding the second set of winding. The difference between the corresponding effective conductors in the first set of winding and the second set of winding is a certain number of stator teeth, and the vector included angle of the two groups of target harmonics is close to 180 degrees, so that the two groups of target harmonics can be mutually offset or weakened, and fundamental waves with larger amplitude can be obtained. The invention also discloses a low-harmonic winding and an axial magnetic motor.

Description

Method for weakening target harmonic, low-harmonic winding and axial flux motor

Technical Field

The invention relates to the technical field of axial flux motors, in particular to a method for weakening target harmonics, a low-harmonic winding and an axial flux motor.

Background

The concentrated winding motor, especially the fractional slot concentrated winding motor, has the advantages of simple manufacturing process, high power density and torque density, small cogging torque and the like, thereby being widely applied. However, the concentrated winding has the defect of rich armature magnetic field harmonic waves, and the rich magnetic field harmonic waves cause the eddy current loss and vibration noise of the motor to be increased, so that the comprehensive performance of the motor is influenced.

Disclosure of Invention

The invention aims to weaken the harmonic wave of an armature magnetic field in a concentrated winding, thereby improving the performance of an axial flux motor.

In order to realize the purpose, the following technical scheme is provided:

a method of attenuating a target harmonic, comprising:

winding a first set of windings;

deducing the number of stator teeth which need to be different between the effective conductors corresponding to the first set of windings and the second set of windings according to a preset vector included angle of two sets of target harmonics, wherein the two sets of target harmonics are respectively generated by the first set of windings and the second set of windings, and when the vector included angle of the two sets of target harmonics is the preset vector included angle, a target effect can be realized, and the target effect comprises the following steps: the two groups of target harmonics cancel or weaken each other;

and counting stator teeth with the number of the stator teeth around the stator iron core by taking the first set of windings as a reference, and then winding a second set of windings.

Preferably, 160 DEG ≦ 200 DEG of the predetermined vectorial angle.

Preferably, the target effect further comprises: two sets of fundamental waves are superimposed, the two sets of fundamental waves being generated by the first set of windings and the second set of windings, respectively.

Preferably, the first and second electrodes are formed of a metal,

designing the structure of the first set of windings according to a rule of a centralized winding and a z/2 slot, wherein the first set of windings and the second set of windings have the same structure;

the first set of winding is specifically wound as follows: winding the first set of windings in stator slots with even serial numbers or stator slots with odd serial numbers;

the second set of winding is specifically wound as follows: and winding the second set of windings in the remaining stator slots.

The invention also discloses a low-harmonic winding, which comprises a first set of winding and a second set of winding, wherein the difference between the corresponding effective conductors in the first set of winding and the second set of winding is a certain number of stator teeth, and two groups of target harmonics generated by the first set of winding and the second set of winding are mutually counteracted or weakened.

Preferably, the two sets of fundamental waves generated by the first set of windings and the second set of windings are superimposed on each other.

Preferably, the number of stator teeth is derived from a predetermined vector angle of the two sets of target harmonics.

Preferably, 160 DEG ≦ 200 DEG of the predetermined vectorial angle.

Preferably, the first set of windings and the second set of windings are three-phase windings, the number of the coils of the first set of windings is the same as that of the coils of the second set of windings, the number z of the slots of the stator cores corresponding to the first set of windings and the second set of windings is an even number, and z is larger than or equal to 6.

Preferably, in any one of the first set of windings and the second set of windings, the corresponding active conductors of the three phase windings differ in sequence by the same number of stator teeth.

Preferably, the z is 24 and the number of poles p is 10, and each phase winding includes 4 coils in any one of the first and second sets of windings.

Preferably, the first coil of the first phase winding of the first set of windings enters from 3 slots and penetrates out from 1 slot, the second coil enters from 23 slots and penetrates out from 1 slot, the third coil enters from 13 slots and penetrates out from 15 slots, and the fourth coil enters from 13 slots and penetrates out from 11 slots;

the first coil of the second phase winding of the first set of windings enters from the 5 slots and penetrates out from the 7 slots, the second coil enters from the 5 slots and penetrates out from the 3 slots, the third coil enters from the 19 slots and penetrates out from the 17 slots, and the fourth coil enters from the 15 slots and penetrates out from the 17 slots;

the first coil of the third phase winding of the first set of windings enters from the 11 slots and penetrates out of the 9 slots, the second coil enters from the 7 slots and penetrates out of the 9 slots, the third coil enters from the 21 slots and penetrates out of the 23 slots, and the fourth coil enters from the 21 slots and penetrates out of the 19 slots.

Preferably, the first coil of the first phase winding of the second set of windings enters from 8 slots and exits from 6 slots, the second coil enters from 4 slots and exits from 6 slots, the third coil enters from 18 slots and exits from 20 slots, and the fourth coil enters from 18 slots and exits from 16 slots;

the first coil of the second phase winding of the second set of windings enters from 10 slots and penetrates out from 12 slots, the second coil enters from 10 slots and penetrates out from 8 slots, the third coil enters from 24 slots and penetrates out from 22 slots, and the fourth coil enters from 20 slots and penetrates out from 22 slots;

the first coil of the third phase winding of the second set of windings enters from 16 slots and penetrates out from 14 slots, the second coil enters from 12 slots and penetrates out from 14 slots, the third coil enters from 2 slots and penetrates out from 4 slots, and the fourth coil enters from 2 slots and penetrates out from 24 slots.

The invention also discloses an axial flux motor which comprises a winding, wherein the winding is any one of the low-harmonic windings.

According to the technical scheme, the two sets of windings, namely the first set of winding and the second set of winding, are wound on the stator iron core. Particularly, the difference between the corresponding effective conductors in the first set of winding and the second set of winding is a certain number of stator teeth, so that the vector included angle of two sets of target harmonics generated by the first set of winding and the second set of winding is a preset vector included angle, the preset vector included angle is 180 degrees or close to 180 degrees, therefore, the two sets of target harmonics can be mutually offset or weakened, meanwhile, fundamental waves with large amplitude can be obtained, and the performance of the axial flux motor is improved.

Drawings

In order to more clearly illustrate the solution of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without inventive efforts.

FIG. 1 is a diagram illustrating two sets of target harmonics with vectors at 180 degrees according to an embodiment of the present invention;

FIG. 2 is a coil layout of a first set of windings according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a first phase winding in a first set of windings according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a second phase winding of the first set of windings according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a first set of windings wound in odd numbered stator slots of a stator core according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a 10-pole 24-slot winding according to an embodiment of the present invention;

fig. 7 is a comparison graph of harmonics generated by the low harmonic winding of the present invention and the conventional winding.

Detailed Description

A method of attenuating a target harmonic that eliminates or attenuates the target harmonic to improve performance of an axial flux machine is disclosed. The invention also discloses a low-harmonic winding and an axial magnetic motor.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

Applicants have found that the harmonics affecting an axial flux machine are typically harmonics of some order or orders that are the target harmonics to be eliminated. If the target harmonic is eliminated, the performance of the axial flux machine is significantly improved. To this end, applicants have creatively designed methods and low harmonic windings to attenuate the target harmonic.

The method of attenuating the target harmonic comprises the steps of: firstly, winding a first set of windings; and then deducing the number of stator teeth which need to be different between the effective conductors corresponding to the first set of windings and the second set of windings according to a preset vector included angle of two sets of target harmonics, wherein the two sets of target harmonics are respectively generated by the first set of windings and the second set of windings, and when the vector included angle of the two sets of target harmonics is the preset vector included angle, a target effect can be realized, and the target effect comprises the following steps: the two groups of target harmonics cancel or weaken each other; and finally, taking the first set of windings as a reference, counting the number of stator teeth with a phase difference around the stator iron core, and then winding the second set of windings.

When the second set of windings is rotated relative to the first set of windings

After the angle, the target harmonic corresponding to the second set of windings is rotated relative to the target harmonic corresponding to the first set of windings

Where "k" is the order of the target harmonic. Therefore, after the predetermined vector included angle of the two groups of target harmonics is determined, the number of the stator teeth which need to be different between the second set of windings and the first set of windings can be calculated. Hair brushObviously, the preset vector included angle of the two groups of target harmonics is optimized as follows: 160 DEG-200 DEG of the predetermined vector angle. The vector angle of the two sets of target harmonics is optimally 180 deg. in terms of attenuation of the target harmonics.

When the vector included angle of the two groups of target harmonics is 180 degrees, the vector amplitude of the two groups of target harmonics after synthesis is zero, namely the two groups of target harmonics are completely eliminated. Referring to fig. 1, two groups of target harmonics are denoted by D1 and D2 in fig. 1, respectively, and are completely eliminated when D1 and D2 are at an included angle as shown in fig. 1, i.e., 180 °.

It should be noted that, in actual operation, when the number of stator teeth that must be different between the first set of windings and the second set of windings is calculated according to the predetermined vector angle of the two sets of target harmonics, the obtained number of stator teeth may be a fraction, and then the closest integer value is required. This problem will be described in detail below with reference to specific examples.

Further, when the elimination of the target harmonic is considered, the fundamental wave is considered at the same time. Both sets of windings can generate fundamental waves. The vector directions of the two groups of fundamental waves are the same, the amplitude of the synthesized two groups of fundamental waves is the largest, and the fundamental waves are useful waves. Therefore, the predetermined vector pinch values of the two sets of target harmonics are determined with the object of attenuating the target harmonics as much as possible and making the vector directions of the two sets of fundamental waves as much as possible the same, so that the fundamental waves having a large amplitude can be obtained while the target harmonics can be attenuated to the maximum extent.

The first set of windings and the second set of windings are three-phase windings and have the same structure, so that the target harmonic waves with the same order can be generated better. The invention is illustrated by taking as an example the winding process of the first set of windings. In one embodiment, the number of slots z of the stator core corresponding to the first set of windings is 24, and the corresponding number of poles p is 10. It should be noted that, because the first set of windings and the second set of windings have the same structure, and both the two sets of windings are three-phase windings, the number z of slots of the stator core is even, and z is greater than or equal to 6.

When a first set of windings is wound, firstly, a coil distribution diagram of the first set of windings is designed according to a rule of concentrated windings and a z/2 slot, as shown in fig. 2, fig. 2 is the coil distribution diagram of the first set of windings provided by the present invention. The three phase windings of the first set of windings are obtained from the coil profile of the first set of windings as shown in fig. 3 and 4. Fig. 3 is a schematic structural diagram of a first phase winding in a first set of windings provided by the present invention, and fig. 4 is a schematic structural diagram of a second phase winding in the first set of windings provided by the present invention. Then winding A1 phase winding in odd numbered stator slots of the stator core, counting 2 stator teeth along the counterclockwise direction, and then winding B1 phase winding in odd numbered stator slots. Referring to fig. 5, fig. 5 is a schematic structural diagram illustrating a first set of windings wound in odd numbered stator slots of a stator core according to the present invention.

It should be noted that the difference between the effective conductors corresponding to the a1 phase winding and the B1 phase winding is 4 stator teeth, not 2 stator teeth, please refer to fig. 5 and fig. 6. The effective conductor corresponding to the effective conductor at the A1 outlet end in the B1 phase winding is not the effective conductor at the B1 outlet end, but the effective conductor in the 7 slots and the effective conductor at the B1 outlet end form a coil of the B1 phase winding. The effective conductor of the A1 outlet end is positioned in 3 slots, the corresponding effective conductor in the B1 winding is positioned in 7 slots, and therefore, the difference between the effective conductors corresponding to the A1 phase winding and the B1 phase winding is 4 stator teeth.

After the winding of the B1 phase winding is finished, 6 stator teeth are counted along the anticlockwise direction, and then the C1 phase winding is wound in stator slots with odd serial numbers. Since the first set of windings is wound only in odd numbered stator slots, the pitch y of the first set of windings is 2.

Similarly, the phase difference between the effective conductors corresponding to the phase winding B1 and the phase winding C1 is 4 stator teeth, not 6 stator teeth. With continued reference to fig. 5 and 6, the effective conductor corresponding to the effective conductor at the B1 outlet end in the C1 phase winding is not the effective conductor at the C1 outlet end, but is the effective conductor in 9 slots, and the effective conductor in 9 slots and the effective conductor at the C1 outlet end form a coil of the C1 phase winding. The effective conductor of the B1 outlet end is positioned in 5 slots, the effective conductor corresponding to the B1 winding is positioned in 9 slots, and therefore, the difference between the effective conductors corresponding to the B1 phase winding and the C1 phase winding is 4 stator teeth.

For a 10 pole, 24 slot axial flux machine, the 7 th harmonic has the greatest effect on the performance of the axial flux machine, and therefore the 7 th harmonic is the target harmonic. If the vector angle of the two groups of target harmonics is 180 degrees, the space angle between the effective conductors corresponding to the first set of windings and the second set of windings is 77.14 degrees, at the moment, the vector angle of the two sets of fundamental waves is 25.7 degrees, and the amplitude value after the two sets of fundamental waves are synthesized is larger. However, since the number z of slots of the stator core is 24, one stator tooth corresponds to 15 °, the number of the stator teeth needs to be an integer, and the spatial angle between the effective conductors corresponding to the two sets of windings is only an integer multiple of 15 °, so that the spatial angle is 75 °. 75 is an integer multiple of 15 and is closest to 77.14. 75 ° corresponds to 5 stator teeth.

The stator teeth number which is required to be different between the effective conductors corresponding to the first set of windings and the second set of windings is deduced, and then the starting slot wound by the second set of windings can be found. The specific operation is as follows: and taking the effective conductor at the A1 outlet end as a reference, counting 5 stator teeth in a reverse clock direction, wherein a groove between the 5 th stator tooth and the 6 th stator tooth is an initial groove for winding the second set of winding, and then winding the second set of winding. The second set of windings is wound in even numbered stator slots of the stator core. Since the structure of the second set of windings is completely the same as the structure of the first set of windings, the winding method is also the same, and therefore, the description thereof is omitted.

The invention also discloses a low-harmonic winding, which comprises a first set of winding and a second set of winding, wherein the difference between the corresponding effective conductors in the first set of winding and the second set of winding is a certain number of stator teeth. The two groups of target harmonics generated by the first set of windings and the second set of windings cancel or weaken each other, and the two groups of fundamental waves generated by the first set of windings and the second set of windings are superposed with each other.

The number of stator teeth which are different between the first set of windings and the second set of windings is deduced from the preset vector included angle of the two sets of target harmonics, and the preset vector included angle of the two sets of target harmonics is optimized as follows: 160 DEG-200 DEG of the predetermined vector angle.

The vector angle of the two sets of target harmonics is optimally 180 deg. in terms of attenuation of the target harmonics. After the predetermined vector included angle of the two groups of target harmonics is determined, the number of the stator teeth which are different between the first set of windings and the second set of windings can be calculated.

In order to optimize the effect of attenuating the target harmonic, the first set of windings and the second set of windings are arranged as three-phase windings, and the number of coils of the first set of windings and the second set of windings is the same. Further, in any one of the first set of windings and the second set of windings, the corresponding effective conductors of the three phase windings are sequentially different from each other by the same number of stator teeth, so that the electrical phase angles between the three phase windings are ensured to be 120 degrees.

When the slot number z is 24 and the pole number p is 10, each phase winding includes 4 coils. Referring to fig. 6, fig. 6 is a schematic structural diagram of a 10-pole 24-slot winding provided by the present invention, and a structure of a first set of windings is as follows:

the first coil of the first phase winding of the first set of windings enters from the 3 slots and penetrates out of the 1 slot, the second coil enters from the 23 slots and penetrates out of the 1 slot, the third coil enters from the 13 slots and penetrates out of the 15 slot, and the fourth coil enters from the 13 slots and penetrates out of the 11 slot;

the first coil of the second phase winding of the first set of windings enters from the 5 slots and penetrates out from the 7 slots, the second coil enters from the 5 slots and penetrates out from the 3 slots, the third coil enters from the 19 slots and penetrates out from the 17 slots, and the fourth coil enters from the 15 slots and penetrates out from the 17 slots;

the first coil of the third phase winding of the first set of windings enters from slot 11 and exits from slot 9, the second coil enters from slot 7 and exits from slot 9, the third coil enters from slot 21 and exits from slot 23, and the fourth coil enters from slot 21 and exits from slot 19.

With continued reference to fig. 6, the structure of the second set of windings is as follows:

the first coil of the first phase winding of the second set of windings enters from 8 slots and penetrates out of 6 slots, the second coil enters from 4 slots and penetrates out of 6 slots, the third coil enters from 18 slots and penetrates out of 20 slots, and the fourth coil enters from 18 slots and penetrates out of 16 slots;

the first coil of the second phase winding of the second set of windings enters from the 10 slots and penetrates out from the 12 slots, the second coil enters from the 10 slots and penetrates out from the 8 slots, the third coil enters from the 24 slots and penetrates out from the 22 slots, and the fourth coil enters from the 20 slots and penetrates out from the 22 slots;

the first coil of the third phase winding of the second set of windings enters from 16 slots and exits from 14 slots, the second coil enters from 12 slots and exits from 14 slots, the third coil enters from 2 slots and exits from 4 slots, and the fourth coil enters from 2 slots and exits from 24 slots.

It should be noted that the stator slots are numbered for convenience of description only, and that a certain coil must enter and exit from a stator slot with a specific number is not necessarily the case, and only the relative position relationship between the coils is protected.

Referring to fig. 7, fig. 7 is a graph comparing the harmonics generated by the low harmonic winding of the present invention and the conventional winding. As can be seen from fig. 7, the target harmonic (7 th order) in this case is significantly attenuated compared to the conventional scheme, while the fundamental (5 th order) remains substantially unchanged.

The invention also discloses an axial magnetic motor which comprises a winding, wherein the winding is any one of the low-harmonic windings. The low-harmonic winding has the above effects, and the axial flux motor having the low-harmonic winding also has the above effects, so the details are not described herein.

Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (14)

1. A method of attenuating a target harmonic, comprising:

winding a first set of windings;

deriving the number of stator teeth which need to be different between effective conductors corresponding to the first set of windings and the second set of windings according to a predetermined vector included angle of two sets of target harmonics, wherein the two sets of target harmonics are respectively generated by the first set of windings and the second set of windings, and a target effect can be realized when the vector included angle of the two sets of target harmonics is the predetermined vector included angle, and the target effect comprises: the two groups of target harmonics cancel or weaken each other;

and counting stator teeth with the number of the stator teeth around the stator iron core by taking the first set of windings as a reference, and then winding a second set of windings.

2. The method of attenuating target harmonics according to claim 1, wherein the predetermined vectorial included angle is 160 ° ≦ 200 °.

3. The method of attenuating target harmonics of claim 1, wherein the target effect further comprises: two sets of fundamental waves are superimposed, the two sets of fundamental waves being generated by the first set of windings and the second set of windings, respectively.

4. The method of attenuating target harmonics according to claim 1,

designing the structure of the first set of windings according to a rule of a centralized winding and a z/2 slot, wherein the first set of windings and the second set of windings have the same structure;

the first set of winding is specifically wound as follows: winding the first set of windings in stator slots with even serial numbers or stator slots with odd serial numbers;

the second set of winding is specifically wound as follows: and winding the second set of windings in the remaining stator slots.

5. A low-harmonic winding is characterized by comprising a first set of windings and a second set of windings, wherein corresponding effective conductors in the first set of windings and the second set of windings are different by a certain number of stator teeth, and two sets of target harmonics generated by the first set of windings and the second set of windings are mutually counteracted or weakened.

6. The low harmonic winding of claim 5 wherein the two sets of fundamental waves generated by the first set of windings and the second set of windings are superimposed on each other.

7. The low harmonic winding of claim 5 wherein the stator tooth counts are derived from predetermined vector angles of the two sets of target harmonics.

8. The low harmonic winding of claim 7 wherein the predetermined vectorized included angle is 160 ° or less and 200 ° or less.

9. The low-harmonic winding of claim 5, wherein the first set of windings and the second set of windings are three-phase windings, the number of coils of the first set of windings is the same as that of the second set of windings, the number z of slots of the stator core corresponding to the first set of windings and the second set of windings is an even number, and z is greater than or equal to 6.

10. The low harmonic winding of claim 9 wherein corresponding active conductors of three phase windings differ in sequence by the same number of stator teeth in either of the first and second sets of windings.

11. The low harmonic winding of claim 9 wherein z is 24 and p is 10, and wherein each phase winding comprises 4 coils in either of the first and second sets of windings.

12. The low harmonic winding of claim 11 wherein the first coil of the first phase winding of the first set of windings enters from slot 3 and exits from slot 1, the second coil enters from slot 23 and exits from slot 1, the third coil enters from slot 13 and exits from slot 15, and the fourth coil enters from slot 13 and exits from slot 11;

the first coil of the second phase winding of the first set of windings enters from the 5 slots and penetrates out from the 7 slots, the second coil enters from the 5 slots and penetrates out from the 3 slots, the third coil enters from the 19 slots and penetrates out from the 17 slots, and the fourth coil enters from the 15 slots and penetrates out from the 17 slots;

the first coil of the third phase winding of the first set of windings enters from the 11 slots and penetrates out of the 9 slots, the second coil enters from the 7 slots and penetrates out of the 9 slots, the third coil enters from the 21 slots and penetrates out of the 23 slots, and the fourth coil enters from the 21 slots and penetrates out of the 19 slots.

13. The low harmonic winding of claim 11 wherein the first coil of the first phase winding of the second set of windings enters from 8 slots and exits from 6 slots, the second coil enters from 4 slots and exits from 6 slots, the third coil enters from 18 slots and exits from 20 slots, and the fourth coil enters from 18 slots and exits from 16 slots;

the first coil of the second phase winding of the second set of windings enters from 10 slots and penetrates out from 12 slots, the second coil enters from 10 slots and penetrates out from 8 slots, the third coil enters from 24 slots and penetrates out from 22 slots, and the fourth coil enters from 20 slots and penetrates out from 22 slots;

the first coil of the third phase winding of the second set of windings enters from 16 slots and penetrates out from 14 slots, the second coil enters from 12 slots and penetrates out from 14 slots, the third coil enters from 2 slots and penetrates out from 4 slots, and the fourth coil enters from 2 slots and penetrates out from 24 slots.

14. An axial flux electric machine comprising a winding, wherein the winding is a low harmonic winding as claimed in any one of claims 5 to 13.

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