CN107579606B - A kind of low vibration is made an uproar the fractional-slot concentratred winding magneto and design method of performance - Google Patents

Abstract

The invention discloses a fractional slot concentrated winding permanent magnet motor with low vibration and noise performance and a design method. It belongs to the field of rotating electrical machines. On the basis of the original motor with slot and pole matching, several stator additional teeth are correspondingly added (the specific number depends on the slot and pole matching of the motor). Taking the three-phase 18/16 motor as an example, add 6 additional teeth, calculate the slot position of each stator, and adopt the concentrated winding structure corresponding to the three-phase 18/16 motor for the winding structure. The rotor structure adopts a common surface-mount structure and is magnetized radially. The invention has the advantage that, by changing the structure of the stator, the content of tooth harmonics in the magnetomotive force of the winding in the air gap is reduced, thereby reducing the vibration and noise of the motor while ensuring the torque of the motor. In addition, the subharmonic content of the magnetomotive force in the air gap is reduced due to the change in the stator structure, which in turn reduces the eddy current losses generated in the permanent magnets. Therefore, the present invention has great significance for the body design of the motor.

Description

A fractional slot concentrated winding permanent magnet motor with low vibration and noise performance and its design method

technical field

The invention relates to a motor manufacturing technology, in particular to a technology for reducing loss and vibration of a fractional slot concentrated winding motor.

Background technique

The stator structure of the traditional fractional slot concentrated winding permanent magnet motor is symmetrical. The concentrated winding structure can generate a large magnetomotive force in the air gap of the motor and improve the back EMF and output torque of the motor. However, the biggest disadvantage of the fractional slot concentrated winding permanent magnet motor is that the energized winding will generate a variety of magnetomotive force harmonics in the air gap. Among these magnetomotive force harmonics, only the one with the same frequency as the rotor rotation Sub-harmonics can act to generate output torque, and other sub-harmonics will generate huge eddy current losses in the permanent magnet of the motor rotor, especially for surface-mounted motors, the generated eddy current losses will deteriorate the heat dissipation of the motor. In addition to the heat dissipation problem to be solved, the vibration and noise of the fractional slot concentrated winding permanent magnet motor are also a major problem to be overcome. In order to solve these disadvantages, how to weaken the magnetomotive force harmonics of fractional slot concentrated winding permanent magnet motors is gradually studied.

The document IEEE 2013 International Electric Machines & Drives Conference, (ANovel Tooth Concnetrated Winding with Low Space Harmonic Contents) changed the traditional winding connection method of fractional slot concentrated winding, and creatively used the "star-delta" winding connection method to eliminate the low space generated by the winding. subharmonic content. Although many new structures and methods have been continuously proposed to reduce the winding magnetomotive force harmonics of fractional slot concentrated windings, they are all based on the consumption of a part of the output torque. Moreover, the harmonic attenuation methods that have been researched cannot attenuate some specific harmonics. Let the stator teeth of the motor be Z, and the number of rotor pole pairs be p, then we call the kZ±P harmonics as tooth harmonics. The tooth harmonic and the working wave have the same winding factor, so when the winding factor of the tooth harmonic is changed in a general way, the content of the working wave will be affected accordingly, thereby affecting the output torque. At the same time, the existence of tooth harmonics, especially the existence of Z-pth harmonics, makes the motor have a lot of iron loss, eddy current loss and vibration noise. Inevitably reduce the output performance of the motor. Therefore, it is very meaningful to adopt a new stator structure and winding connection method to reduce the tooth harmonic content of the magnetomotive force in the air gap.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem of a large number of magnetomotive force harmonics in the air-gap magnetic field of the stator and rotor of the original fractional slot concentrated winding motor, and propose a simple, effective and easy-to-execute method. While ensuring the effective increase of torque, the loss and vibration noise of the motor are reduced. The motor structure of the present invention is used in the topology of a rotating electrical machine. Since the essence of this method is to change the distance between the two sides of the winding coil, it is only related to the winding teeth and coils of the motor, so the stator structure and the winding connection method are also the same Suitable for linear motors and disc motors. In order to realize above-mentioned effect, technical scheme of the present invention is:

A fractional slot permanent magnet motor with low vibration and noise performance is designed to further reduce the harmonics of the magnetomotive force generated by the fractional slot windings, thereby reducing the loss and vibration noise caused by the harmonics.

The technical scheme of the present invention is:

A low-vibration and noise characteristic fractional slot concentrated winding permanent magnet motor, including a stator and a rotor; there is an air gap between the stator and the rotor; the stator is slotted to form symmetrical stator teeth, asymmetric stator teeth and additional stator teeth; the stator teeth are wound with Coil A, coil B; the winding connection method follows the slot potential star diagram; the rotor is a common surface-mounted structure, containing a permanent magnet array, the stator is not completely symmetrical on the entire circumference, and different stator tooth structures are designed to reduce the winding. The tooth harmonic content in the air gap generates MMF harmonics, ultimately reducing losses, vibration and noise in the motor.

Further, the symmetrical stator teeth, the asymmetrical stator teeth and the additional stator teeth satisfy the relationship: the angle corresponding to the symmetrical stator teeth is 2θ ₃ , the angle corresponding to the asymmetric stator teeth is θ ₃ +θ ₄ , and the angle corresponding to the additional stator teeth is 2θ ₅ , the coil A spans the asymmetric stator teeth and the additional stator teeth, B spans the symmetrical stator teeth, θ _y represents the angle spanned by the coil in the winding, then the pitch factor of the motor satisfies the following formula:

In the formula, v represents the number of pole pairs corresponding to the magnetomotive force harmonic generated by the winding in the air gap. For the fractional slot concentrated winding, the value of _θy can be expressed as:

Among them, Z represents the number of stator teeth of the motor; in addition, the following formula is also satisfied:

For a three-phase 18/16 motor, the number of pole pairs of the harmonics of the fundamental wave corresponding to the magnetomotive force is 8, k _p8 is the pitch factor of the winding magnetomotive force corresponding to the fundamental wave, and kd ₈ is the distribution of the fundamental wave winding magnetomotive force Factors, meanwhile, the sizes of the symmetric stator teeth, asymmetric stator teeth and additional stator teeth satisfy the constraints:

6θ ₃ +12(θ ₃ +θ ₄ )+12θ ₅ =2π.

Further, the permanent magnet array is composed of permanent magnets of equal size, which are magnetized according to the radial direction, and the directions of magnetization are alternated.

Further, the permanent magnet array can also use the Halbach array for magnetic concentration, and the thickness of the air gap between the stator and the rotor is 0.5mm.

The technical scheme of the method of the present invention is: a design method of a low-vibration and noise characteristic fractional slot concentrated winding permanent magnet motor, comprising the following steps:

Step 1. Select the pole-slot coordination of the permanent magnet motor with fractional slot concentrated winding, connect the windings through the slot potential star diagram method, use the point current method to equivalent the current in the winding to the position of the slot, and calculate the air gap of the energized winding in the motor Winding magnetomotive force generated in, and calculate notch factor K _sv , distribution factor K _qv and pitch factor K _yv corresponding to v pole harmonic magnetomotive force;

Step 2: Perform Fourier decomposition on the magnetomotive force generated by the energized winding in the air gap, obtain the winding magnetomotive force component corresponding to the fundamental wave, and calculate the notch factor K _sp and the distribution of the fundamental wave content corresponding to the winding magnetomotive force Factor K _qp and pitch factor K _yp ; because the slots are matched and fixed, the distribution factor and pitch factor remain unchanged, and the notch factor is approximately 1 and ignored. At this time, the pitch corresponding to the fundamental component should be increased Factor to increase the magnetomotive force component, let the fundamental wave pitch factor take the maximum value of 1, and find the corresponding winding pitch at this time;

Step 3. According to the new winding pitch, add corresponding additional teeth to the stator part of the motor. If it is a three-phase 18/16 motor, add 6 additional teeth. At this time, the winding connection method is still in accordance with the traditional three-phase 18/16 The 16-fraction slot concentrated winding motor is phase-separated, which ensures that the notch factor K _sv and distribution factor K _qv corresponding to the magnetomotive force generated by the winding remain unchanged, and the pitch factor K _yv corresponding to the fundamental component of the winding increases to 1 , and the pitch factor corresponding to the tooth harmonic, that is, the kZ±P harmonic content is reduced, thereby reducing the percentage of the tooth harmonic to the fundamental wave content, thereby reducing the vibration and noise characteristics of the motor.

Further, the permanent magnet array is composed of permanent magnets of equal size, which are magnetized according to the radial direction, and the directions of magnetization are alternated.

Further, the permanent magnet array can also use the Halbach array for magnetic concentration, and the thickness of the air gap between the stator and the rotor is 0.5 mm.

Further, the symmetrical stator teeth, the asymmetrical stator teeth and the additional stator teeth satisfy the relationship: the angle corresponding to the symmetrical stator teeth is 2θ ₃ , the angle corresponding to the asymmetric stator teeth is θ ₃ +θ ₄ , and the angle corresponding to the additional stator teeth is 2θ ₅ , the coil A spans the asymmetric stator teeth and the additional stator teeth, B spans the symmetrical stator teeth, θ _y represents the angle spanned by the coil in the winding, then the pitch factor of the motor satisfies the following formula:

In the formula, v represents the number of pole pairs corresponding to the magnetomotive force harmonic generated by the winding in the air gap. For the fractional slot concentrated winding, the value of _θy can be expressed as:

Among them, Z represents the number of stator teeth of the motor; in addition, the following formula is also satisfied:

For a three-phase 18/16 motor, the number of pole pairs of the harmonics of the fundamental wave corresponding to the magnetomotive force is 8, k _p8 is the pitch factor of the winding magnetomotive force corresponding to the fundamental wave, and kd ₈ is the distribution of the fundamental wave winding magnetomotive force Factors, meanwhile, the sizes of the symmetric stator teeth, asymmetric stator teeth and additional stator teeth satisfy the constraints:

6θ ₃ +12(θ ₃ +θ ₄ )+12θ ₅ =2π.

The invention mainly includes the design of novel stator structure, winding connection mode and rotor structure. The stator includes a stator yoke, a stator tooth, and a stator slot. The winding is composed of a coil made of copper wire. The coil is wound on the stator tooth and placed in the stator slot. The direct mechanical angle on both sides of the coil is θ, and there will be an air gap between the stator and the rotor. The energized winding will generate a magnetomotive force in the air gap. After the magnetomotive force is decomposed by Fourier, it can be converted into and the winding in the air gap. Harmonic components associated with the number of pole pairs v of the magnetomotive harmonics. At this time, v has three main factors affecting the polar harmonic content, the notch factor K _sv , the distribution factor K _qv and the pitch factor K _yv . When calculating the winding magnetomotive force, the point current method is generally used, that is, the winding current is concentrated at the center point of the notch position. At this time, the notch width is equivalent to 0, and the value of the notch factor is approximately 1, so The magnetomotive force generated by the winding in the air gap is only related to the distribution factor and the pitch factor. This method takes a three-phase 18/16 motor as an example, creatively adds 6 auxiliary stator teeth between the three phases, and ensures that the electric load of the motor remains unchanged. At this time, the entire stator teeth are grouped with four adjacent teeth. , there are three groups on the entire circumference. Each set of stator teeth is divided into three different teeth, namely one symmetrical tooth a, two asymmetrical teeth b, and one symmetrical tooth c. Through theoretical analysis, it can be concluded that the angle corresponding to the three teeth of abc is:

The connection method of the winding coil is connected according to the slot potential star diagram of the three-phase 18/16 motor, to ensure the maximum magnitude of the magnetomotive force synthesized by each phase, and the coil span of each phase is θ’=π/8. At this time, it can be ensured that the pitch factor of the magnetomotive force corresponding to the 8 pairs of harmonics (that is, the working wave) is 1, and the amplitude of the fundamental wave is correspondingly increased to increase the torque density. The amplitude of the same 10-pair harmonic content is greatly reduced, which reduces the radial force wave of the motor, and finally reduces the vibration and noise of the motor.

The invention uses surface-mounted permanent magnets, and Halbach permanent magnet arrays can be considered to enhance the magnetic concentration and increase the torque density.

The object of the present invention is a fractional slot permanent magnet motor with low vibration and noise performance. This scheme has the following advantages:

(1) Creatively add additional teeth in the stator, and separate the working wave from the kz±p (k is a positive integer) order tooth harmonic through a specific winding method, and only reduce the amplitude of the tooth harmonic, thereby It reduces the magnetomotive force tooth harmonic generated by the winding in the air gap, and reduces the low-order radial force wave, thereby reducing the vibration and noise of the motor.

(2) The present invention effectively reduces the low magnetic harmonic content generated by the energized winding in the air gap, reduces the magnetic flux leakage of the motor, reduces the eddy current loss, controls the temperature of the rotor during high-speed motion, and can reduce the risk of irreversible demagnetization risk.

(3) The present invention can increase the amplitude of the working wave of the magnetomotive force of the winding, thereby ensuring the torque density of the motor.

(4) Permanent magnets can be considered to be embedded, surface-embedded and surface-mounted. In addition, surface-embedded and surface-mounted permanent magnets can also be considered to use Halbach permanent magnet arrays to enhance magnetic concentration and increase torque density.

(5) The motor structure of the present invention is applicable to various types of motors, including rotary motors, flat linear motors, cylindrical linear motors and disk motors. The shape design of stator teeth depends on the matching of slots and poles, and the principle is universal.

Description of drawings

Fig. 1 is an overall schematic diagram of a fractional slot permanent magnet motor with low vibration and noise performance according to the present invention.

Fig. 2 is a schematic diagram of the amplification principle of the stator tooth structure change of the fractional slot permanent magnet motor with low vibration and noise performance of the present invention.

Fig. 3 is an enlarged schematic diagram of the stator structure of the fractional slot permanent magnet motor with low vibration and noise performance according to the present invention.

Fig. 4 is a schematic diagram of the comparison of the winding magnetomotive force spectrum analysis of the traditional three-phase 18/16 fractional slot concentrated winding motor and the fractional slot permanent magnet motor with low vibration and noise performance of the present invention.

Fig. 5 is a schematic diagram showing the comparison of iron loss and eddy current loss between the traditional three-phase 18/16 fractional slot concentrated winding motor and the fractional slot permanent magnet motor with low vibration and noise performance of the present invention.

Fig. 6 is a schematic diagram of sound power comparison between the traditional three-phase 18/16 fractional slot concentrated winding motor and the fractional slot permanent magnet motor with low vibration and noise performance of the present invention.

Detailed ways

Referring to Fig. 1, the present invention is a method for reducing the vibration and noise characteristics of a fractional slot concentrated winding permanent magnet motor. The vibration and noise of the motor are affected by the tooth harmonics generated by the energized windings in the air gap. The higher the tooth harmonic content, the higher the tooth harmonic content. The greater the vibration and noise of the motor. The present invention includes an outer stator 1, which contains three kinds of teeth, symmetrical teeth 15, asymmetrical teeth 16, and additional teeth 17. Motor slot potential star diagram 200, in general, a wave with a sinusoidal distribution in any space can be represented by a space vector, therefore, the magnetomotive force wave generated by each coil can be represented by a line segment, and the arrow represents the vector direction. The angle between each vector is equal to the spatial phase difference of the represented magnetomotive force harmonics, spaced apart by one wavelength, and the difference is 2π (radian) in the vector diagram, and the vector length represents the corresponding magnetomotive force the magnitude of . In fact, the vectors of all the coils that make up the winding can be added together with the vector generator to obtain the v-pole magnetomotive force harmonics generated by the entire winding. This is the basic principle and method of analyzing the winding magnetomotive force by the slot potential star diagram . In practical applications, in order to facilitate the determination of the vector direction, all the z slots of the motor can be regarded as evenly distributed z conductors carrying the same direction and the same current. At this time, the appropriate lengths should be equal. When analyzing the slot potential star diagram of the opposite pole of v, the angle between the two vectors of adjacent slot numbers is equal to v times the slot pitch angle, and the slot pitch angle can be expressed as:

As shown in FIG. 1 , 200 is a three-phase 18/16 motor working wave, that is, a magnetomotive star diagram corresponding to 8 pairs of poles. With the slot potential star diagram, the actual motor windings can be connected accordingly. The vector direction of the conductor carrying positive current is the same as the slot vector direction of the slot number in which the conductor is embedded, and the vector direction of the conductor carrying negative current is the same as that of the slot number in which the conductor is embedded. The direction of the slot vector for the slot number is opposite. Lines cross to indicate current inflow, and hollow circles indicate current outflow, that is, forward winding coil 101 and reverse winding coil 102. The span of each coil is equal, and the specific size depends on the number of stator slots of the selected motor and the number of pole pairs of permanent magnets. Certainly. There is an air gap between the stator and the rotor, and the specific air gap thickness is determined according to the size of the motor and related requirements. The inner rotor adopts the traditional surface mount type.

The outer stator 1 adds several additional teeth to the original stator teeth. The number of teeth and the dimensions of the symmetrical teeth 15, the asymmetrical teeth 16 and the additional teeth 17 depend on the matching of specific motor slot sets. Figure 1 is a three-phase 18/16 double-layer winding motor stator as an example. In practical application, the winding structure can be single-layer or double-layer structure, and the stator tooth structure can be changed accordingly.

Fig. 2 is a schematic diagram of the amplification principle of the stator tooth structure change in the present invention. The angle θ _y formed by the center position O of the motor rotor and the slot of the stator 1 where the coil is located is the influencing factor of the pitch factor of the winding magnetomotive force. At this time, the pitch factor corresponding to the polar harmonic of v can be expressed as:

Referring to Fig. 2, the principle of this invention is to change the included angle θ _y , the traditional motor included angle is θ ₁ , the invention included angle is θ ₂ , which satisfies the pitch factor K _pv = 1 corresponding to the fundamental wave, that is, the working wave, and increases The magnitude of the fundamental magnetomotive force increases the torque density.

A partially enlarged schematic diagram of the stator 1 is shown in FIG. 3 . The rotor 2 adopts a common surface mount structure, and the permanent magnet 300 adopts radial magnetization. The 300 pole arc coefficients of the permanent magnets of each module are consistent. The mechanical angle spanned by the forward winding coil 101 and the reverse winding coil 102 is the same, and the pitch factor corresponding to the fundamental wave is 1. The included angles corresponding to the symmetrical tooth 15, the asymmetrical tooth 16, and the additional tooth 17 are 2θ ₃ , θ ₃ +θ ₄ , and 2θ ₅ respectively. In order to ensure that the pitch factor corresponding to the fundamental wave is 1, at this time, the teeth 15, 16, 17 should satisfy the formula:

The pitch factor corresponding to the fundamental wave is 1, then k _pc8 =1, and the angles corresponding to the symmetrical tooth 15, the asymmetrical tooth 16, and the additional tooth 17 are 22.5 degrees, 15 degrees, and 7.5 degrees. At this time, the angle calculated is based on the three-phase 18/16 motor as an example. The size of the 1st tooth of the stator is different according to the calculation of different slots and poles. At the same time, it can be seen from the figure that the forward winding coil 101 spans an additional tooth 17 and an asymmetrical tooth 16, and the reverse winding coil 102 spans a symmetrical tooth 15, which is different from the traditional fractional slot concentrated winding structure, but The winding connection method of the present invention is the same as the winding connection method of the traditional fractional slot concentrated winding structure, and the division of positive and negative phase bands of the coil is completely consistent. The difference is that the present invention makes use of the spatial position angle generated by the additional teeth to make the spans generated by the coil 101 and the coil 102 equal, which ensures the maximum value of the magnetomotive force of the winding combination, and at the same time, destroys the relationship between the working wave and the tooth harmonic The corresponding relationship makes the corresponding tooth harmonic content not change when the working wave amplitude is changed.

Fig. 4 is a schematic diagram of the comparison of the winding magnetomotive force spectrum analysis of the traditional three-phase 18/16 fractional slot concentrated winding motor and the fractional slot permanent magnet motor with low vibration and noise performance of the present invention. In the figure, A is the traditional three-phase 18/16 fractional slot concentrated winding motor winding magnetomotive force spectrum analysis, and B is a schematic diagram of the winding magnetomotive force spectrum analysis comparison of the fractional slot permanent magnet motor with low vibration and noise performance. It can be seen that, The z-p, z+p, 2z-p, 2z+p... sub-tooth harmonic content of the improved motor is significantly reduced. (z represents the number of stator teeth of the motor, and p represents the number of permanent magnet pole pairs). Before and after the improvement, the size, electric load and current density of the motor remain unchanged. The working wave of the motor, that is, the amplitude of the 8-pair harmonic wave remains unchanged, so that the torque of the motor is not affected. Compared with the working wave of the motor, the 10 pairs of pole-tooth harmonics are reverse waves, so they have a huge impact on the vibration and noise of the motor. It can be seen from the figure that the ratio of the 10-pair polar harmonic content to the fundamental wave content is reduced by 25.3%. This is also one of the important reasons for this design scheme to reduce the vibration and noise of the motor.

In said Fig. 4, the harmonic content of 2 pairs of poles has been reduced by about 40%. At this time, as shown in Fig. 5, it is the traditional three-phase 18/16 fractional slot concentrated winding motor and the fractional slot permanent magnet with low vibration and noise performance of the present invention Schematic diagram of the iron loss and eddy current loss comparison of the motor. A1 in the figure is the stator iron loss and the eddy current loss generated in the rotor permanent magnet of the traditional three-phase 18/16 fractional slot concentrated winding motor, and B1 is the stator iron loss and rotor permanent magnet of the fractional slot permanent magnet motor with low vibration and noise performance Eddy current losses generated in the body. It can be seen from the comparison that the eddy current loss of the permanent magnet motor with low vibration and noise characteristics of the invention is reduced by 30.1%, and the iron loss of the stator remains basically unchanged. During the operation of the motor, the eddy current loss generated inside the permanent magnet is closely related to the temperature of the motor. The eddy current loss is larger, and the higher the temperature generated. Generally, the traditional fractional slot concentrated winding permanent magnet motor adopts the cooling scheme of natural cooling, so it is particularly important to reduce the eddy current loss generated inside the permanent magnet during the operation of the motor. Moreover, as the temperature increases, the permanent magnet itself has the problem of demagnetization. Controlling the value of eddy current loss can advantageously reduce the risk of permanent magnet demagnetization. This is also one of the advantages of the invention.

Fig. 6 is a schematic diagram of sound power comparison between the traditional three-phase 18/16 fractional slot concentrated winding motor and the fractional slot permanent magnet motor with low vibration and noise performance of the present invention. A2 in the figure is the sound power of the traditional three-phase 18/16 fractional slot concentrated winding motor at different frequencies, and B2 is the sound power of the fractional slot permanent magnet motor with low vibration and noise performance of the present invention. It can be seen that at 1200Hz and 4300Hz, the sound power of the motor is reduced the most, from 84.33dB to 74dB, and the noise level is reduced by 84.12% in total. From the perspective of reducing vibration and noise, this invention has achieved a very ideal Effect. The reduction of vibration and noise solves many problems existing in the operation of the motor, which is also the main significance of the research of the present invention.

In the description of this specification, references to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" are intended to mean that the implementation A specific feature, structure, material, or characteristic described by an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (7)

1. The characteristic fractional-slot concentratred winding magneto 1. a kind of low vibration is made an uproar, which is characterized in that include stator (1), rotor (2)；It is fixed There is air gap between sub (1) and rotor (2)；

   Stator (1) fluting forms symmetrical stator tooth (15), asymmetric stator tooth (16) and additional stator tooth (17)；On stator tooth It is wound with winding, winding includes loop A (101) and coil B (102), and loop A (101) is wound on asymmetric stator tooth (16) and adds On stator tooth (17), coil B (102) is wound on symmetrical stator tooth (15)；Winding connection is according to the star-like figure of slot potential (200)；Rotor (2) is surface-mount type structure, and containing permanent magnet array (300), stator (1) is not full symmetric in whole circumference , different stator toothings is designed, the slot ripples content of mmf harmonics is generated to reduce winding in air gap, it is final to reduce Loss, vibration and the noise of motor；

   The symmetrical stator tooth (15), asymmetric stator tooth (16) and additional stator tooth (17) meet relationship: symmetrical stator tooth (15) corresponding angle is 2 θ₃, the corresponding angle of asymmetric stator tooth (16) is θ₃+θ₄, the corresponding angle of additional stator tooth (17) For 2 θ₅, θ_yIndicate loop A (101) in winding or coil B (102) across angle, then the pitch factor of motor meets following Formula:

   In formula, v indicates the corresponding number of pole-pairs of mmf harmonics that winding generates in air gap, for fractional-slot concentratred winding Speech, θ_yValue indicate are as follows:

   Wherein, Z indicates the number of stator teeth of motor；In addition, also meeting following formula:

   For 18/16 motor of three-phase, the corresponding mmf harmonics number of pole-pairs of fundamental wave is 8, k_p8For the corresponding winding magnetomotive force of fundamental wave Pitch factor, kd₈For the magnetomotive distribution factor of fundamental wave winding, meanwhile, symmetrical stator tooth (15), asymmetric stator tooth (16) And the size of additional stator tooth (17) meets constraint condition:

   6θ₃+12(θ₃+θ₄)+12θ₅=2 π.
2. 2. a kind of low characteristic fractional-slot concentratred winding magneto of making an uproar that shakes according to claim 1, it is characterized in that: permanent magnet battle array (300) are arranged by equal-sized set of permanent magnets at according to radial magnetizing, magnetizing direction alternating.
3. 3. a kind of low characteristic fractional-slot concentratred winding magneto of making an uproar that shakes according to claim 1, it is characterized in that: permanent magnet battle array Column (300) carry out poly- magnetic using Halbach array, and air gap thickness takes 0.5mm between stator (1) and rotor (2).
4. The design side of characteristic fractional-slot concentratred winding magneto 4. a kind of low vibration according to claim 1-3 is made an uproar Method, which comprises the following steps:

   Step 1, the pole slot cooperation for selecting fractional-slot concentratred winding magneto carries out winding company by the star-like figure method of slot potential It connects, current equivalence in winding to notch position is calculated into the winding that energization winding generates in motor gas-gap using a current method Magnetomotive force, and calculate v notch factor K corresponding to pole harmonic wave magnetomotive force_sv, distribution factor K_qvWith pitch factor K_yv, v is winding The corresponding number of pole-pairs of the mmf harmonics generated in air gap；

   Step 2, Fourier decomposition is carried out to the magnetomotive force that energization winding generates in air gap, it is dynamic finds out the corresponding winding magnetic of fundamental wave Gesture component calculates the notch factor K in the corresponding fundamental wave content of winding magnetomotive force_sp, distribution factor K_qpWith fundamental wave pitch factor K_yp；Since slot number is matched and is fixed, so distribution factor and pitch factor K_yvIt remains unchanged, while notch factor is approximately 1, this When to increase the corresponding fundamental wave pitch factor K of fundametal compoment_ypTo increase magnetomotive force component, fundamental wave pitch factor K is enabled_ypIt takes most Big value 1, finds out corresponding winding pitch at this time；

   Step 3, according to new winding pitch, increase corresponding additional teeth in the stationary part of motor, guarantee the magnetic that winding generates The corresponding notch factor K of kinetic potential_svWith distribution factor K_qvIt remains unchanged, at this time the corresponding fundamental wave pitch factor of winding fundametal compoment K_ypIncreasing is 1, and the corresponding pitch factor of slot ripples, that is, kZ ± P subharmonic content reduces, so that reducing slot ripples accounts for fundamental wave The percentage of content, the characteristic so that vibration for reducing motor is made an uproar；Wherein, k is positive integer, and Z indicates the number of stator teeth of motor, and P is Permanent magnet pole logarithm.
5. The design method of characteristic fractional-slot concentratred winding magneto 5. the low vibration of one kind according to claim 4 is made an uproar, it is special Sign is that permanent magnet array (300) is by equal-sized set of permanent magnets at according to radial magnetizing, magnetizing direction alternating.
6. The design method of characteristic fractional-slot concentratred winding magneto 6. the low vibration of one kind according to claim 4 is made an uproar, it is special Sign is that permanent magnet array (300) carries out poly- magnetic using Halbach array, and air gap thickness takes between stator (1) and rotor (2) 0.5mm。
7. The design method of characteristic fractional-slot concentratred winding magneto 7. the low vibration of one kind according to claim 4 is made an uproar, it is special Sign is that symmetrical stator tooth (15), asymmetric stator tooth (16) and additional stator tooth (17) meet relationship: symmetrical stator tooth (15) corresponding angle is 2 θ₃, the corresponding angle of asymmetric stator tooth (16) is θ₃+θ₄, the corresponding angle of additional stator tooth (17) For 2 θ₅, loop A (101) is across asymmetric stator tooth (16) and additional stator tooth (17), and coil B (102) is across symmetrical stator tooth (15), θ_yIndicate winding center line circle across angle, then the pitch factor of motor meets following formula:

   In formula, v indicates the corresponding number of pole-pairs of mmf harmonics that winding generates in air gap, for fractional-slot concentratred winding Speech, θ_yValue indicate are as follows:

   Wherein, Z indicates the number of stator teeth of motor；In addition, also meeting following formula:

   For 18/16 motor of three-phase, the corresponding mmf harmonics number of pole-pairs of fundamental wave is 8, k_p8For the corresponding winding magnetomotive force of fundamental wave Pitch factor, kd₈For the magnetomotive distribution factor of fundamental wave winding, meanwhile, symmetrical stator tooth (15), asymmetric stator tooth (16) And the size of additional stator tooth (17) meets constraint condition:

   6θ₃+12(θ₃+θ₄)+12θ₅=2 π.