CN105449968A - Composite magnetic pole type surface-mounted permanent magnet synchronous motor - Google Patents

Abstract

The invention discloses a composite magnetic pole type surface-mounted permanent magnet synchronous motor, which belongs to the field of permanent magnet motors. The composite magnetic pole type surface-mounted permanent magnet synchronous motor aims to solve the problems that harmonic wave is in the presence in a sinusoidal-current-driven rare earth permanent magnet synchronous motor air gap magnetic field and local irreversible demagnetization always happen. The composite magnetic pole type surface-mounted permanent magnet synchronous motor comprises a rotor and a stator, wherein the rotor is arranged in the stator; a radial air gap is formed between the rotor and the stator; the excircle surface of the a rotor iron core is evenly provided with a plurality of rotor magnetic pols in a surface-mounted way; each rotor magnetic pole comprises a rare earth permanent magnetic pole and two ferrite permanent magnetic poles, wherein the left end surface and the right end surface of the rare earth permanent magnetic pole are independently provided with one ferrite permanent magnetic pole; the rare earth permanent magnetic pole and two ferrite permanent magnetic poles form a continuous circular-arc magnetic pole structure; and the magnetization directions of the rare earth permanent magnetic pole and two ferrite permanent magnetic poles are all radial magnetization and are the same. The permanent magnet synchronous motor of the structure causes the harmonic content of the air gap magnetic field to be lowered, motor efficiency is improved, the ferrite permanent magnet material is low in price, and cost is lowered.

Description

Composite poles formula Surface Mount permagnetic synchronous motor

Technical field

The present invention relates to a kind of rotor structure of composite poles formula, belong to magneto field.

Background technology

Day by day serious along with problems such as Environment and energy crises, energy-efficient electric equipment becomes development trend, facilitates the development of high power density, high efficiency rare earth permanent-magnet synchronization motor thus greatly.But the price of rare earth permanent-magnetic material remains high always, and rare-earth permanent-magnet electric machine affects larger by rare earth permanent-magnetic material price fluctuation, therefore the cost of rare-earth permanent-magnet electric machine is also affected thereupon, and higher cost has greatly reduced the development space of rare earth permanent-magnet synchronization motor.And rare earth material belongs to non-renewable resources, rare earth material consumption too much in electric system also can damage environment.Therefore, under the prerequisite ensureing motor performance, the energy-saving efficient motor system of the few rare earth material of research, is not only the needs of energy strategy, especially for the consideration of environmental protection.

For the rare earth permanent-magnet synchronization motor of sine wave drive, the air-gap field distribution that permanent magnetic material produces is always containing harmonic components, and these harmonic fields can cause extra iron loss and torque ripple; And local irreversible demagnetization in use easily appears in rare earth permanent-magnetic material, especially in the case of a high temperature, permanent magnetic material irreversible demagnetization will cause the decline of motor performance.

Summary of the invention

There is harmonic wave and easily occur the problem of local irreversible demagnetization in the rare earth permanent-magnet synchronization motor air-gap field that the present invention seeks to solve sine wave drive, especially in the case of a high temperature, permanent magnetic material irreversible demagnetization will cause the problem of the decline of motor performance, provides a kind of composite poles formula Surface Mount permagnetic synchronous motor.Not affecting under motor output performance prerequisite, both reducing rare-earth permanent-magnet electric machine cost, rare-earth permanent-magnet electric machine air-gap field sine degree can have been improved again, solution high temperature demagnetization problem had just had realistic meaning.

Composite poles formula Surface Mount permagnetic synchronous motor of the present invention, comprise rotor and stator, rotor is arranged on the inside of stator, leaves radial air gap between rotor and stator, stator comprises stator core and stator winding, arranges stator winding in the internal stator groove of stator core; Rotor comprises multiple rotor magnetic pole and rotor core, and the outer round surface surface-mount type of rotor core is evenly provided with multiple rotor magnetic pole;

Rotor magnetic pole comprises rare earth permanent magnet magnetic pole and two ferrite permanent-magnet magnetic poles; About two end faces of rare earth permanent magnet magnetic pole arrange a ferrite permanent-magnet magnetic pole respectively, and rare earth permanent magnet magnetic pole and two ferrite permanent-magnet magnetic poles form continuous circular arc shape field structure; The magnetizing direction of rare earth permanent magnet magnetic pole and two ferrite permanent-magnet magnetic poles is radial magnetizing, and magnetizing direction is identical.

Advantage of the present invention: the composite poles formula Surface Mount PMSM Air Gap Flux irregularity of wave form that the present invention proposes diminishes, but the close amplitude of its magnetic also diminishes because introducing the less Ferrite Material of remanent magnetism thereupon, for ensureing that the traditional surface-mount type rare earth permanent-magnet synchronization motor shown in the fan-out capability of motor and Fig. 1 is consistent, add the axial length of composite poles motor, but composite poles formula motor cost is still low than pure rare earth magneto.As shown in Figure 4, the air gap magnetic density waveform of the composite poles formula Surface Mount permagnetic synchronous motor that the present invention proposes is more sinusoidal than traditional surface-mount type rare earth permanent-magnet synchronization motor, thus reduces stator iron loss and torque ripple.In addition, the strong anti-demagnetization capability of Ferrite Material reduces demagnetization risk when motor runs, and improves the reliability of motor.

Accompanying drawing explanation

Fig. 1 is a kind of traditional surface-mount type rare earth permanent-magnet synchronization motor structural representation;

Fig. 2 is the structural representation of composite poles formula Surface Mount permagnetic synchronous motor of the present invention;

Fig. 3 is the concrete structure schematic diagram of the knockdown rotor magnetic pole of motor of the present invention;

Fig. 4 is the air gap magnetic density waveform comparison diagram of composite poles formula Surface Mount permagnetic synchronous motor of the present invention and traditional surface-mount type rare earth permanent-magnet synchronization motor.

Embodiment

Embodiment one: present embodiment is described below in conjunction with Fig. 2 to Fig. 4, composite poles formula Surface Mount permagnetic synchronous motor described in present embodiment, comprise rotor and stator, rotor is arranged on the inside of stator, radial air gap is left between rotor and stator, stator comprises stator core 1 and stator winding 2, arranges stator winding 2 in the internal stator groove of stator core 1; Rotor comprises multiple rotor magnetic pole 3 and rotor core 4, and the outer round surface surface-mount type of rotor core 4 is evenly provided with multiple rotor magnetic pole 3;

Rotor magnetic pole 3 comprises rare earth permanent magnet magnetic pole 3-1 and two ferrite permanent-magnet magnetic pole 3-2; About two end faces of rare earth permanent magnet magnetic pole 3-1 arrange a ferrite permanent-magnet magnetic pole 3-2 respectively, and rare earth permanent magnet magnetic pole 3-1 and two ferrite permanent-magnet magnetic pole 3-2 forms continuous circular arc shape field structure; The magnetizing direction of rare earth permanent magnet magnetic pole 3-1 and two ferrite permanent-magnet magnetic pole 3-2 is radial magnetizing, and magnetizing direction is identical.

In order to reach this purpose, design of the present invention is: for traditional surface-mount type rare earth permanent-magnet synchronization motor, replace a part of rare earth permanent-magnetic material with ferrite permanent-magnet materials, ferrite is positioned over rare earth permanent-magnetic material both sides.Because Ferrite Material remanent magnetism is lower than rare earth permanent-magnetic material remanent magnetism, air gap magnetic density waveform can be made more close to sinusoidal wave by combination, reduce the harmonic content of air-gap field, thus the stator iron loss and torque ripple that magnetic field harmonics causes can be reduced.In addition, the anti-demagnetization capability of ferrite permanent-magnet materials is better than rare earth permanent-magnetic material, and the anti-demagnetization capability of ferrite permanent-magnet materials raises with temperature and strengthens, ferrite is positioned over the local demagnetization risk that rare earth material both sides can reduce rare earth permanent-magnetic material originally greatly, improves running reliability of motor.This composite poles formula magneto utilizes ferrite permanent-magnet materials with low cost to replace a part of rare earth permanent-magnetic material, reduces cost, makes efficiency and operational reliability increase simultaneously.

The anti-demagnetization capability of ferrite permanent-magnet magnetic pole 3-2 being positioned over rare earth permanent magnet magnetic pole 3-1 both sides is comparatively strong, and its coercive force has positive temperature coefficient, and during high temperature, anti-demagnetization capability can be strengthened further, and when can improve practical application, rare earth permanent-magnetic material high temperature easily demagnetizes problem.

The overall width of pole parts 3 of the present invention is identical with the rare earth permanent magnet magnetic pole in Fig. 1 with thickness; For ensure motor fan-out capability and Fig. 1 shown in traditional surface-mount type rare earth permanent-magnet synchronization motor be consistent, need the axial length of increase composite poles motor, but composite poles formula motor cost is still low than pure rare earth magneto.

Embodiment two: present embodiment is described further execution mode one, rare earth permanent magnet magnetic pole 3-1 arc length is a, and ferrite permanent-magnet magnetic pole 3-2 arc length is b/2, and the two meets following condition:

$\frac{\sqrt{\frac{a{\left({\mathrm{Br}}_2\right)}^2+b{\left({\mathrm{Br}}_1\right)}^2}{c}}-\frac{2}{\mathrm{\π}}\{2\left({\mathrm{Br}}_2\right)sin\left(\frac{a}{2c}\mathrm{\π}\right)+2\left({\mathrm{Br}}_1\right)\[sin\left(\frac{a+b}{2c}\mathrm{\π}\right)-sin\left(\frac{a}{2c}\mathrm{\π}\right)\]\}}{\frac{2}{\mathrm{\π}}\{2\left({\mathrm{Br}}_2\right)\sin \left(\frac{a}{2c}\mathrm{\π}\right)+2\left({\mathrm{Br}}_1\right)\[\sin \left(\frac{a+b}{2c}\mathrm{\π}\right)-\sin \left(\frac{a}{2c}\mathrm{\π}\right)\]\}}\≤2\%$

In formula: c is the pole span of rotor magnetic pole 3;

Br ₂for rare earth permanent magnet magnetic pole 3-1 residual flux density at the working temperature; Br ₁for ferrite permanent-magnet magnetic pole 3-2 residual flux density at the working temperature; And meet Br ₂>Br ₁.

Carry out rational proportion by the size of above-mentioned formula to rare earth permanent magnet magnetic pole 3-1 and ferrite permanent-magnet magnetic pole 3-2, make it produce the best air-gap field waveform of sine degree, thus be conducive to reducing iron loss and torque ripple.

Claims (2)

1. composite poles formula Surface Mount permagnetic synchronous motor, comprise rotor and stator, rotor is arranged on the inside of stator, radial air gap is left between rotor and stator, stator comprises stator core (1) and stator winding (2), arranges stator winding (2) in the internal stator groove of stator core (1); Rotor comprises multiple rotor magnetic pole (3) and rotor core (4), and the outer round surface surface-mount type of rotor core (4) is evenly provided with multiple rotor magnetic pole (3);

It is characterized in that, rotor magnetic pole (3) comprises rare earth permanent magnet magnetic pole (3-1) and two ferrite permanent-magnet magnetic poles (3-2); About two end faces of rare earth permanent magnet magnetic pole (3-1) arrange a ferrite permanent-magnet magnetic pole (3-2) respectively, and rare earth permanent magnet magnetic pole (3-1) and two ferrite permanent-magnet magnetic poles (3-2) form continuous circular arc shape field structure; The magnetizing direction of rare earth permanent magnet magnetic pole (3-1) and two ferrite permanent-magnet magnetic poles (3-2) is radial magnetizing, and magnetizing direction is identical.

2. composite poles formula Surface Mount permagnetic synchronous motor according to claim 1, it is characterized in that, rare earth permanent magnet magnetic pole (3-1) arc length is a, and ferrite permanent-magnet magnetic pole (3-2) arc length is b/2, and the two meets following condition:

$\frac{\sqrt{\frac{a{\left({\mathrm{Br}}_2\right)}^2+b{\left({\mathrm{Br}}_1\right)}^2}{c}}-\frac{2}{\mathrm{\π}}\{2\left({\mathrm{Br}}_2\right)sin\left(\frac{a}{2c}\mathrm{\π}\right)+2\left({\mathrm{Br}}_1\right)\[sin\left(\frac{a+b}{2c}\mathrm{\π}\right)-sin\left(\frac{a}{2c}\mathrm{\π}\right)\]\}}{\frac{2}{\mathrm{\π}}\{2\left({\mathrm{Br}}_2\right)\sin \left(\frac{a}{2c}\mathrm{\π}\right)+2\left({\mathrm{Br}}_1\right)\[\sin \left(\frac{a+b}{2c}\mathrm{\π}\right)-\sin \left(\frac{a}{2c}\mathrm{\π}\right)\]\}}\≤2\%$

In formula: c is the pole span of rotor magnetic pole (3);

Br ₂for rare earth permanent magnet magnetic pole (3-1) residual flux density at the working temperature; Br ₁for ferrite permanent-magnet magnetic pole (3-2) residual flux density at the working temperature; And meet Br ₂>Br ₁.