CN105449967A - Combined magnetic pole built-in radial direction V type permanent magnet synchronous motor - Google Patents

Abstract

A combined magnetic pole built-in radial direction V type permanent magnet synchronous motor belongs to the permanent magnet motor field. The invention solves the problem that the air-gap magnetic field of a sine wave driven rare-earth permanent magnet synchronous motor has harmonic waves and is liable to arise irreversible demagnetization. The invention comprises a rotor and a stator; the magnet pole of the rotor is of one layer or multilayer embedded V type permanent magnet structure; the magnetic pole of the rotor comprises two rare-earth permanent magnet poles and two ferrite permanent magnet poles; the two rare-earth permanent magnet poles and the two ferrite permanent magnet poles are long strip shaped; a rare-earth permanent magnet pole and a ferrite permanent magnet pole are embedded in each slope channel of a V type permanent magnet installing groove; the two magnet poles in the same slope channel magnetize parallel to the vertical direction of the slope channel; the magnetizing directions are the same; the magnetizing directions simultaneously face towards the internal part or the external part of the V shape. The permanent magnet synchronous motor of the structure reduces the harmonic wave content of the air-gap magnetic field, improves the efficiency of the motor and reduces the cost because the cost of the ferrite permanent magnet material is low.

Description

Composite poles formula built-in radial V-type 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 local irreversible demagnetization problem 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 built-in radial V-type 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.

The present invention includes two technical schemes:

First technical scheme is individual layer field structure: described composite poles formula built-in radial V-type 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 and stator winding, arranges stator winding in the internal stator groove of stator core; Rotor comprises multiple rotor magnetic pole and rotor core, and rotor core is uniform one deck V-type permanent magnet mounting groove along the circumferential direction, and V-type permanent magnet mounting groove extends vertically, and V-type opening surface is to stator, arranges a rotor magnetic pole in each V-type permanent magnet mounting groove;

Rotor magnetic pole comprises two rare earth permanent magnet magnetic poles and two ferrite permanent-magnet magnetic poles, two rare earth permanent magnet magnetic poles and two ferrite permanent-magnet magnetic poles are strip, all embed 1 rare earth permanent magnet magnetic pole and 1 ferrite permanent-magnet magnetic pole in the every bar ramped aisle of V-type permanent magnet mounting groove;

Rare earth permanent magnet magnetic pole in same ramped aisle and ferrite permanent-magnet magnetic pole are the parallel magnetization with this ramped aisle vertical direction, and magnetizing direction is identical; The magnetizing direction of two rare earth permanent magnet magnetic poles in V-type permanent magnet mounting groove two ramped aisles is simultaneously inner or simultaneously outside to V-shape to V-shape.

Second technical scheme is multilayer magnetic pole structure: described composite poles formula built-in radial V-type 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 and stator winding, arranges stator winding in the internal stator groove of stator core; Rotor comprises multiple rotor magnetic pole and rotor core, rotor core is uniform n layer V-type permanent magnet mounting groove along the circumferential direction, V-type permanent magnet mounting groove extends vertically, the V-type opening surface of each V-type permanent magnet mounting groove is to stator, n the V-type permanent magnet mounting groove be on same Radius is parallel to each other, and arranges a rotor magnetic pole in each V-type permanent magnet mounting groove; N be more than or equal to 2 natural number;

Rotor magnetic pole comprises two rare earth permanent magnet magnetic poles and two ferrite permanent-magnet magnetic poles, two rare earth permanent magnet magnetic poles and two ferrite permanent-magnet magnetic poles are strip, all embed 1 rare earth permanent magnet magnetic pole and 1 ferrite permanent-magnet magnetic pole in the every bar ramped aisle of V-type permanent magnet mounting groove;

Rare earth permanent magnet magnetic pole in same ramped aisle and ferrite permanent-magnet magnetic pole are the parallel magnetization with this ramped aisle vertical direction, and magnetizing direction is identical; The magnetizing direction of two rare earth permanent magnet magnetic poles in V-type permanent magnet mounting groove two ramped aisles is simultaneously inner or simultaneously outside to V-shape to V-shape;

Magnetizing direction with the rotor magnetic pole of the n on Radius is consistent.

Advantage of the present invention: on the basis of the radial V-type rare earth permanent-magnet synchronization motor of conventional internal, replaces a part of rare earth permanent-magnetic material with ferrite permanent-magnet materials, Ferrite Material 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.

Accompanying drawing explanation

Fig. 1 is a kind of conventional internal radial V-type rare earth permanent-magnet synchronization motor structural representation, individual layer field structure;

Fig. 2 is a kind of conventional internal radial V-type rare earth permanent-magnet synchronization motor structural representation, double-layer magnetic electrode structure;

Fig. 3 is the structural representation of composite poles formula built-in radial V-type permagnetic synchronous motor described in execution mode one, individual layer field structure;

Fig. 4 is the structural representation of composite poles formula built-in radial V-type permagnetic synchronous motor described in execution mode two, double-layer magnetic electrode structure;

Fig. 5 is the concrete structure schematic diagram of the knockdown rotor magnetic pole of motor of the present invention;

Fig. 6 is the air gap magnetic density waveform comparison diagram of composite poles formula built-in radial V-type permagnetic synchronous motor of the present invention and traditional built-in radial V-type rare earth permanent-magnet synchronization motor.

Embodiment

Embodiment one: present embodiment is described below in conjunction with Fig. 3, Fig. 5 and Fig. 6, composite poles formula built-in radial V-type 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, rotor core 4 is uniform one deck V-type permanent magnet mounting groove 3-3 along the circumferential direction, V-type permanent magnet mounting groove 3-3 extends vertically, and V-type opening surface is to stator, arranges a rotor magnetic pole 3 in each V-type permanent magnet mounting groove 3-3;

Rotor magnetic pole 3 comprises two rare earth permanent magnet magnetic pole 3-1 and two ferrite permanent-magnet magnetic pole 3-2, two rare earth permanent magnet magnetic pole 3-1 and two ferrite permanent-magnet magnetic pole 3-2 are strip, all embed 1 rare earth permanent magnet magnetic pole 3-1 and 1 ferrite permanent-magnet magnetic pole 3-2 in the every bar ramped aisle of V-type permanent magnet mounting groove 3-3;

Rare earth permanent magnet magnetic pole 3-1 in same ramped aisle and ferrite permanent-magnet magnetic pole 3-2 is the parallel magnetization with this ramped aisle vertical direction, and magnetizing direction is identical; The magnetizing direction of two rare earth permanent magnet magnetic pole 3-1 in V-type permanent magnet mounting groove 3-3 two ramped aisles is simultaneously inner or simultaneously outside to V-shape to V-shape.

In a ramped aisle, rare earth permanent magnet magnetic pole 3-1 is a/2 along the length in direction, slope, and ferrite permanent-magnet magnetic pole 3-2 is b/2 along the length in direction, slope, and the two meets following condition:

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

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

D is two ramped aisle angles of V-type permanent magnet mounting groove 3-3;

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.

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 the pole parts 3 described in present embodiment is identical with the rare earth permanent magnet magnetic pole in Fig. 1 with thickness; By as shown in Figure 6, the composite poles formula built-in radial V-type PMSM Air Gap Flux irregularity of wave form that the present invention proposes obviously diminishes, but the close amplitude of its magnetic also diminishes because introducing the less Ferrite Material of remanent magnetism thereupon, for ensureing that the built-in radial V-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 6, the air gap magnetic density waveform of the composite poles formula built-in radial V-type permagnetic synchronous motor that the present invention proposes is more sinusoidal than conventional internal V-type permagnetic synchronous 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.

Embodiment two: present embodiment is described below in conjunction with Fig. 4 to Fig. 6, composite poles formula built-in radial V-type 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, rotor core 4 is uniform n layer V-type permanent magnet mounting groove 3-3 along the circumferential direction, V-type permanent magnet mounting groove 3-3 extends vertically, the V-type opening surface of each V-type permanent magnet mounting groove 3-3 is to stator, n the V-type permanent magnet mounting groove 3-3 be on same Radius is parallel to each other, and arranges a rotor magnetic pole 3 in each V-type permanent magnet mounting groove 3-3; N be more than or equal to 2 natural number;

Rotor magnetic pole 3 comprises two rare earth permanent magnet magnetic pole 3-1 and two ferrite permanent-magnet magnetic pole 3-2, two rare earth permanent magnet magnetic pole 3-1 and two ferrite permanent-magnet magnetic pole 3-2 are strip, all embed 1 rare earth permanent magnet magnetic pole 3-1 and 1 ferrite permanent-magnet magnetic pole 3-2 in the every bar ramped aisle of V-type permanent magnet mounting groove 3-3;

Rare earth permanent magnet magnetic pole 3-1 in same ramped aisle and ferrite permanent-magnet magnetic pole 3-2 is the parallel magnetization with this ramped aisle vertical direction, and magnetizing direction is identical; The magnetizing direction of two rare earth permanent magnet magnetic pole 3-1 in V-type permanent magnet mounting groove 3-3 two ramped aisles is simultaneously inner or simultaneously outside to V-shape to V-shape;

Magnetizing direction with the rotor magnetic pole of the n on Radius 3 is consistent.

In a ramped aisle of arbitrary one deck, rare earth permanent magnet magnetic pole (3-1) is a along the length in direction, slope _i/ 2, i=1,2 ...., n; , ferrite permanent-magnet magnetic pole (3-2) is b along the length in direction, slope _i/ 2, the two meets following condition:

$\frac{\sqrt{\frac{a_i{\left({\mathrm{Br}}_2\right)}^2+b_i{\left({\mathrm{Br}}_1\right)}^2}{c}sin\left(\frac{d}{2}\right)}-\frac{2}{\mathrm{\π}}\{2\left({\mathrm{Br}}_2\right)sin\left(\frac{a_{i}sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)+2\left({\mathrm{Br}}_1\right)\[sin\left(\frac{(a_i+b_i)sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)-sin\left(\frac{a_{i}sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)\]\}}{\frac{2}{\mathrm{\π}}\{2\left({\mathrm{Br}}_2\right)sin\left(\frac{a_{i}sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)+2\left({\mathrm{Br}}_1\right)\[sin\left(\frac{(a_i+b_i)sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)-sin\left(\frac{a_{i}sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)\]\}}\≤2\%$

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

D is two ramped aisle angles of V-type permanent magnet mounting groove (3-3);

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.

In each Rotating fields, rare earth permanent magnet magnetic pole 3-1 is identical with the size proportioning of ferrite permanent-magnet magnetic pole 3-2.

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.

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 the pole parts 3 described in present embodiment is identical with the rare earth permanent magnet magnetic pole in Fig. 2 with thickness; By as shown in Figure 6, the composite poles formula built-in radial V-type PMSM Air Gap Flux irregularity of wave form that the present invention proposes obviously diminishes, but the close amplitude of its magnetic also diminishes because introducing the less Ferrite Material of remanent magnetism thereupon, for ensureing that the built-in radial V-type rare earth permanent-magnet synchronization motor shown in the fan-out capability of motor and Fig. 2 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 6, the air gap magnetic density waveform of the composite poles formula built-in radial V-type permagnetic synchronous motor that the present invention proposes is more sinusoidal than conventional internal V-type permagnetic synchronous 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.

Claims (4)

1. composite poles formula built-in radial V-type 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), rotor core (4) is uniform one deck V-type permanent magnet mounting groove (3-3) along the circumferential direction, V-type permanent magnet mounting groove (3-3) extends vertically, and V-type opening surface is to stator, a rotor magnetic pole (3) is set in each V-type permanent magnet mounting groove (3-3);

It is characterized in that, rotor magnetic pole (3) comprises two rare earth permanent magnet magnetic poles (3-1) and two ferrite permanent-magnet magnetic poles (3-2), two rare earth permanent magnet magnetic poles (3-1) and two ferrite permanent-magnet magnetic poles (3-2) are strip, all embed 1 rare earth permanent magnet magnetic pole (3-1) and 1 ferrite permanent-magnet magnetic pole (3-2) in the every bar ramped aisle of V-type permanent magnet mounting groove (3-3);

Rare earth permanent magnet magnetic pole (3-1) in same ramped aisle and ferrite permanent-magnet magnetic pole (3-2) are the parallel magnetization with this ramped aisle vertical direction, and magnetizing direction is identical; The magnetizing direction of two rare earth permanent magnet magnetic poles (3-1) in V-type permanent magnet mounting groove (3-3) two ramped aisles is simultaneously inner or simultaneously outside to V-shape to V-shape.

2. composite poles formula built-in radial V-type permagnetic synchronous motor according to claim 1, it is characterized in that, in a ramped aisle, rare earth permanent magnet magnetic pole (3-1) is a/2 along the length in direction, slope, ferrite permanent-magnet magnetic pole (3-2) is b/2 along the length in direction, slope, and the two meets following condition:

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

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

D is two ramped aisle angles of V-type permanent magnet mounting groove (3-3);

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.

3. composite poles formula built-in radial V-type 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), rotor core (4) is uniform n layer V-type permanent magnet mounting groove (3-3) along the circumferential direction, V-type permanent magnet mounting groove (3-3) extends vertically, the V-type opening surface of each V-type permanent magnet mounting groove (3-3) is to stator, n the V-type permanent magnet mounting groove (3-3) be on same Radius is parallel to each other, and arranges a rotor magnetic pole (3) in each V-type permanent magnet mounting groove (3-3); N be more than or equal to 2 natural number;

It is characterized in that, rotor magnetic pole (3) comprises two rare earth permanent magnet magnetic poles (3-1) and two ferrite permanent-magnet magnetic poles (3-2), two rare earth permanent magnet magnetic poles (3-1) and two ferrite permanent-magnet magnetic poles (3-2) are strip, all embed 1 rare earth permanent magnet magnetic pole (3-1) and 1 ferrite permanent-magnet magnetic pole (3-2) in the every bar ramped aisle of V-type permanent magnet mounting groove (3-3);

Rare earth permanent magnet magnetic pole (3-1) in same ramped aisle and ferrite permanent-magnet magnetic pole (3-2) are the parallel magnetization with this ramped aisle vertical direction, and magnetizing direction is identical; The magnetizing direction of two rare earth permanent magnet magnetic poles (3-1) in V-type permanent magnet mounting groove (3-3) two ramped aisles is simultaneously inner or simultaneously outside to V-shape to V-shape;

Magnetizing direction with the rotor magnetic pole of the n on Radius (3) is consistent.

4. composite poles formula built-in radial V-type permagnetic synchronous motor according to claim 3, it is characterized in that, in a ramped aisle of arbitrary one deck, rare earth permanent magnet magnetic pole (3-1) is a along the length in direction, slope _i/ 2, i=1,2 ...., n; , ferrite permanent-magnet magnetic pole (3-2) is b along the length in direction, slope _i/ 2, the two meets following condition:

$\frac{\sqrt{\frac{a_i{\left({\mathrm{Br}}_2\right)}^2+b_i{\left({\mathrm{Br}}_1\right)}^2}{c}sin\left(\frac{d}{2}\right)}-\frac{2}{\mathrm{\π}}\{2\left({\mathrm{Br}}_2\right)sin\left(\frac{a_{i}sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)+2\left({\mathrm{Br}}_1\right)\[sin\left(\frac{(a_i+b_i)sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)-sin\left(\frac{a_{i}sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)\]\}}{\frac{2}{\mathrm{\π}}\{2\left({\mathrm{Br}}_2\right)sin\left(\frac{a_{i}sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)+2\left({\mathrm{Br}}_1\right)\[sin\left(\frac{(a_i+b_i)Sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)-sin\left(\frac{a_{i}sin\left(\frac{d}{2}\right)}{2c}\mathrm{\π}\right)\]\}}\≤2\%$

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

D is two ramped aisle angles of V-type permanent magnet mounting groove (3-3);

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.