CN104795957B - Method for reducing cogging torque of asynchronous start permanent magnet synchronous motor - Google Patents

Abstract

The invention discloses a method for reducing the cogging torque of an asynchronous start permanent magnet synchronous motor. The method is suitable for the asynchronous start permanent magnet synchronous motor, the asynchronous start permanent magnet synchronous motor comprises a stator and a rotor, a permanent magnet is arranged in the rotor, a certain gap exists between the two adjacent permanent magnetic poles of the rotor and all the gaps are equal; stator teeth and stator grooves which are alternately arrayed along a circumferential direction are arranged at the inner side of the stator; rotor teeth and rotor grooves which are alternately arrayed along the circumferential direction are arranged at the outer side of the rotor; one side, facing the stator, of each rotor tooth is a rotor tooth crest. The method is characterized in that a proper rotor tooth crest width is selected according to the actual structural parameters of asynchronous start permanent magnet synchronous motor. The method disclosed by the invention is applied to the asynchronous start permanent magnet synchronous motor, and is beneficial to the stable running of the type of motors.

Description

A kind of method for reducing asynchronous starting permanent magnet synchronous motor cogging torque

Technical field

The present invention relates to a kind of method for reducing asynchronous starting permanent magnet synchronous motor cogging torque.

Background technology

Cogging torque problem is the intrinsic problem of magneto, can affect the stable operation of motor, how to reduce motor Cogging torque is always one of emphasis of magneto research.At present, most cogging torque weakens method and is still confined to Surface-type and the commonly magneto of the monolateral fluting of rotor such as built-in.

The bilateral fluting of rotor of asynchronous starting permanent magnet synchronous motor, is placed with armature winding, rotor slot in stator slot In there is cage-shaped structure winding, stator and rotor cores are overrided to form by punching, can rely on rotor cage winding produce it is asynchronous Self-starting is realized in torque, and is not usually required to controller in stable operation.Asynchronous starting permanent magnet synchronous motor is generally adopted With every pole integer groove, the cogging torque of motor is larger.The presence of cogging torque not only can be to asynchronous starting permanent magnet synchronous motor Self-starting have a negative impact, but also the stable operation of motor can be affected.

The content of the invention

The present invention is in order to solve the above problems, it is proposed that a kind of asynchronous starting permanent magnet synchronous motor cogging torque that reduces Method, this method reduce asynchronous starting permanent magnet synchronous motor cogging torque while, can't to motor performance produce compared with Big impact.

To achieve these goals, the present invention is adopted the following technical scheme that：

A kind of asynchronous starting permanent magnet synchronous motor, including stator and rotor, the internal rotor is placed with permanent magnet, phase There are certain intervals between adjacent two permanent magnetism magnetic poles, and all of interval is equal, has along the circumferential direction on the inside of the stator The stator tooth being alternately arranged and stator slot, there is the rotor tooth and rotor slot being along the circumferential direction alternately arranged on the outside of the rotor.

The stator tooth is stator tooth top towards the side of rotor, and the width of all stator tooth tops is equal and circumferentially Direction is uniformly distributed.

The rotor tooth is rotor tooth top towards the side of stator, and the width of all rotor tooth tops is equal and circumferentially Direction is uniformly distributed.

A kind of method for reducing asynchronous starting permanent magnet synchronous motor cogging torque, comprises the following steps：

(1) according to the structural parameters of asynchronous starting permanent magnet synchronous motor, build in the square distribution of air-gap mmf and produce The harmonic amplitude computation model of raw cogging torque；

(2) harmonic amplitude by producing cogging torque in the square distribution for making air-gap mmf is 0, obtains effectively cutting The rotor addendum width t of weak asynchronous starting permanent magnet synchronous motor cogging torque₁。

In the step (2), when the harmonic amplitude that cogging torque is produced in the square distribution of air-gap mmf is 0, rotor Addendum width t₁For：

Wherein, LCM (Q₁, 2p) and represent Q₁With the least common multiple of 2p；Q₁For the stator number of teeth；P is the number of pole-pairs of motor；K is Positive integer.

The present invention operation principle be：The cogging torque of asynchronous starting permanent magnet synchronous motor can be regarded as fixed by fluting The square distribution of the air-gap mmf that the square distribution of the effective air gap length that son is produced is produced with slotted rotor interacts and produces Raw, the amplitude of each harmonic is affected by rotor addendum width in the square distribution of air-gap mmf, by making air gap magnetic The harmonic amplitude that cogging torque is produced in the square distribution of kinetic potential is 0, can effectively weaken asynchronous starting permanent magnet synchronous motor Cogging torque.

Beneficial effects of the present invention are：

(1) by the width of change rotor tooth top, the teeth groove that can effectively weaken asynchronous starting permanent magnet synchronous motor turns Square, the method is easily achieved, effect is significant；

(2) width of rotor tooth top is only changed, the other structures parameter of motor does not change, and motor performance is produced Affect very little.

Description of the drawings

Fig. 1 is the structural representation of asynchronous starting permanent magnet synchronous motor；

Fig. 2 is the structural representation before and after the change of rotor addendum width；

Fig. 3 is the cogging torque schematic diagram before and after the change of rotor addendum width；

Wherein, 1- stator cores, 2- rotor cores, 3- stator winding, 4- rotor cage windings, 5- permanent magnets, 6- is adjacent Interval between two permanent magnetism magnetic poles, t₀- former rotor addendum width, t₁Width after the change of-rotor addendum width.

Specific embodiment：

Below in conjunction with the accompanying drawings the invention will be further described with embodiment.

As Figure 1-Figure 2, a kind of method for reducing asynchronous starting permanent magnet synchronous motor cogging torque, two neighboring turn There are certain intervals (6) between sub- permanent magnetism magnetic pole, and all of interval (6) are equal.It is synchronously electronic according to asynchronous starting and permanent magnet The main structure parameters of machine, by the width of rotor tooth top t is changed into₁When, the cogging torque of motor will be significantly attenuated, wherein：

Wherein, LCM (Q₁, 2p) and represent Q₁With the least common multiple of 2p；Q₁For the stator number of teeth；P is the number of pole-pairs of motor；K is Positive integer.

Asynchronous starting permanent magnet synchronous motor original rotor addendum width shown in Fig. 1 is 5.8225 °, its stator number of teeth Q₁= 72, number of pole-pairs p=4, can be calculated can effectively weaken motor cogging torque rotor addendum width be t₁=5 °.Motor Rotor addendum width be respectively 5.8225 °, 5 ° when cogging torque fig. 3, it is shown that by change rotor tooth top width Degree, the cogging torque maximum of motor is cut down to 20Nm by 38Nm, reduces 47.4%.

As shown in Fig. 2 the only rotor addendum width that the method changes, will not produce larger shadow to the performance of motor Ring, and the method be easily achieved, effect is significant.

The present invention principle of realizing be：The cogging torque of asynchronous starting permanent magnet synchronous motor can be regarded as fixed by fluting The square distribution of the air-gap mmf that the square distribution of the effective air gap length that son is produced is produced with slotted rotor interacts and produces Raw, the amplitude of each harmonic is affected by rotor addendum width in the square distribution of air-gap mmf, by making air gap magnetic The harmonic amplitude that cogging torque is produced in the square distribution of kinetic potential is 0, can effectively weaken asynchronous starting permanent magnet synchronous motor Cogging torque.

Although the above-mentioned accompanying drawing that combines is described to the specific embodiment of the present invention, not to present invention protection model The restriction enclosed, one of ordinary skill in the art should be understood that on the basis of technical scheme those skilled in the art are not Need the various modifications made by paying creative work or deformation still within protection scope of the present invention.

Claims (1)

1. a kind of method for reducing asynchronous starting permanent magnet synchronous motor cogging torque, is characterized in that：

Asynchronous starting permanent magnet synchronous motor, including stator and rotor, the internal rotor is placed with permanent magnet, it is two neighboring forever There are certain intervals between magnetic magnetic pole, and all of interval is equal；Have on the inside of the stator and be along the circumferential direction alternately arranged Stator tooth and stator slot, have the rotor tooth and rotor slot being along the circumferential direction alternately arranged on the outside of the rotor；The stator Tooth is stator tooth top towards the side of rotor, and the width of all stator tooth tops is equal and is distributed uniformly and circumferentially；Institute It is rotor tooth top that rotor tooth is stated towards the side of stator, and the width of all rotor tooth tops is equal and along the circumferential direction uniformly divides Cloth；

The method comprising the steps of：

(1) according to the structural parameters of asynchronous starting permanent magnet synchronous motor, in the square distribution for building air-gap mmf tooth is produced The harmonic amplitude computation model of groove torque；

(2) harmonic amplitude by producing cogging torque in the square distribution for making air-gap mmf is 0, obtains effectively weakening different The rotor addendum width t of step starting permanent-magnet synchronous motor cogging torque₁；

In the step (2), when the harmonic amplitude that cogging torque is produced in the square distribution of air-gap mmf is 0, rotor tooth top Width t₁For：

$t_1=\frac{2k\mathrm{\π}}{LCM(Q_1,2p)}$

Wherein, LCM (Q₁, 2p) and represent Q₁With the least common multiple of 2p；Q₁For the stator number of teeth；P is the number of pole-pairs of motor；K is just whole Number.