CN219351384U - Halbach permanent magnet synchronous motor rotor with few rare earth combined magnetic poles - Google Patents

Abstract

A Halbach permanent magnet synchronous motor rotor with few rare earth combined magnetic poles relates to the technical field of motors. The utility model aims to solve the problem that the existing rare earth permanent magnet synchronous motor is large in rare earth permanent magnet material consumption. Each pole permanent magnet comprises m main magnets and 2n auxiliary magnets, n auxiliary magnets are respectively arranged on two sides of the m main magnets in the circumferential direction, each main magnet comprises a non-rare-earth material layer and a rare-earth neodymium-iron-boron layer which are sequentially arranged from inside to outside along the radial direction, and the auxiliary magnets and the non-rare-earth material layers are all non-rare-earth ferrite. The rare earth permanent magnet material has small dosage, and can effectively get rid of excessive dependence on the rare earth permanent magnet material. The motor magnetic flux density is low, the motor iron loss can be reduced, and the motor operation efficiency is high. The rotating speed regulating range of the surface-mounted permanent magnet synchronous motor can be widened.

Description

A Halbach Permanent Magnet Synchronous Motor Rotor with Fewer Rare Earth Combined Pole

technical field

The utility model belongs to the technical field of motors.

Background technique

Rare earth permanent magnet synchronous motors have the advantages of high power density, high efficiency, simple structure and easy speed regulation, and are widely used in various industries. However, rare earth permanent magnet materials are non-renewable resources. With the development of the industry, there is a greater demand for rare earth products, which intensifies the gap between supply and demand of rare earth permanent magnet materials. In recent years, the sharp increase in the price of rare earth permanent magnet materials has led to an increase in the manufacturing cost of rare earth permanent magnet synchronous motors, of which the cost of rare earth permanent magnets will account for 20% of the total cost of rare earth permanent magnet motors. Figure 1 shows two existing structures of rare earth permanent magnet synchronous motors. The motor torque performance of this structure is good, but the amount of rare earth permanent magnets is large, and the manufacturing cost of the motor is high.

Utility model content

The utility model is to solve the problem that the existing rare earth permanent magnet synchronous motor has a large amount of rare earth permanent magnet materials, and now provides a Halbach permanent magnet synchronous motor with less rare earth combined magnetic poles that can give full play to the advantages of the high torque density of the permanent magnet synchronous motor rotor.

A Halbach permanent magnet synchronous motor rotor with few rare earth combined magnetic poles, including permanent magnets and rotor iron cores, the permanent magnets are arranged on the outer circumference of the rotor iron core in a Halbach array structure, and each pole permanent magnet includes m pieces of main magnets. magnets and 2n auxiliary magnets, wherein m and n are both positive integers, n auxiliary magnets are provided on both sides of the m main magnets in the circumferential direction, and each main magnet includes non-rare earth material layer and rare earth NdFeB layer, the auxiliary magnet and the non-rare earth material layer are non-rare earth ferrite, the magnetization direction of the m main magnets in the same pole is the same, and they are all the same as the m main magnets The overall radial center line is parallel, and the magnetization directions of the main magnets in adjacent two poles are opposite.

满足下式：When the radial centerline of the m main magnets in any pole is taken as the reference line, and the magnetization direction of the m main magnets faces away from the center of the rotor core, the magnetization angle of the i-th auxiliary magnet

Satisfies the following formula:

满足下式：When the radial centerline of the m main magnets in any one pole is taken as the reference line, and the magnetization direction of the m main magnetic poles faces the center of the rotor core, then the magnetization angle of the i-th auxiliary magnet

Satisfies the following formula:

为第i块辅助磁体充磁方向与基准线的夹角，且位于基准线顺时针方向的夹角角度为负值，位于基准线逆时针方向的夹角角度为正值。Among them, p=2 is the number of pole pairs of the motor, i=1,2,...,4pn, 3≤m+2n≤6, _θi is the angle between the radial centerline of the i-th auxiliary magnet and the reference line, so Magnetization Angle

is the angle between the magnetization direction of the i-th auxiliary magnet and the reference line, and the included angle in the clockwise direction of the reference line is a negative value, and the included angle in the counterclockwise direction of the reference line is a positive value.

Further, the overall arc length of the m main magnets in each pole is equal to the arc length of each auxiliary magnet;

Or, the overall arc length of the m main magnets in each pole is greater than the arc length of each auxiliary magnet;

Alternatively, the overall arc length of the m main magnets in each pole is smaller than the arc length of each auxiliary magnet.

Further, the above-mentioned rare earth NdFeB layer includes radially arranged outer arcs and inner arcs, and the arc length of the outer arcs is longer than that of the inner arcs.

In the utility model, the combined magnetic pole adopts non-rare earth and rare earth permanent magnet materials, which is more conducive to improving the torque density of the motor compared with the non-rare earth permanent magnet synchronous motor. At the same time, the Halbach array can increase the air gap magnetic flux density, combining the two The combination of advantages can effectively improve the electromagnetic torque of the motor. Compared with the prior art, the utility model can realize technical improvements in the following four aspects:

(1) The amount of rare earth permanent magnet materials is small, which can effectively get rid of the excessive dependence on rare earth permanent magnet materials.

(2) With the help of the Halbach structure of magnetic concentration and the combination of magnetic poles, the electromagnetic torque is improved, and the electromagnetic torque performance of the motor is better.

(3) Compared with the existing rare earth permanent magnet synchronous motor, the motor adopting the rotor of the utility model has a low magnetic flux density, can reduce the iron loss of the motor, has high operating efficiency of the motor, and fully exerts the advantages of high efficiency of the permanent magnet synchronous motor.

(4) Compared with the existing surface-mounted permanent magnet synchronous motor, the permanent magnet flux linkage of the motor adopting the rotor of the utility model is low, which can widen the speed regulation range of the surface-mounted permanent magnet synchronous motor.

Description of drawings

Figure 1 is a schematic diagram of the rotor structure of two traditional rare earth permanent magnet synchronous motors, wherein (a) is a surface-mounted rare earth permanent magnet synchronous motor, and (b) is a rare earth Halbach permanent magnet synchronous motor;

Fig. 2 is the structural representation of the Halbach permanent magnet synchronous motor of a kind of rare earth combined magnetic pole;

Fig. 3 is the structural representation of the Halbach permanent magnet synchronous motor rotor of a kind of few rare earth combined magnetic pole;

Fig. 4 is a schematic diagram of the magnetization angle of the auxiliary magnet, wherein (a) indicates that the magnetization direction of the reference line is towards the center of the rotor core, and (b) indicates that the magnetization direction of the reference line is facing away from the center of the rotor core;

Fig. 5 is m=2, when n=1, the structural representation of the rotor of the Halbach permanent magnet synchronous motor with few rare earth combined magnetic poles;

Fig. 6 is m=1, when n=2, the structural representation of the rotor of the Halbach permanent magnet synchronous motor with few rare earth combined magnetic poles;

Fig. 7 is a schematic diagram of the rotor structure with different radial thicknesses of the main magnet and the auxiliary magnet, wherein (a) indicates that the thickness of the main magnet is greater than that of the auxiliary magnet, and (b) indicates that the thickness of the main magnet is smaller than that of the auxiliary magnet;

Fig. 8 is a structural schematic diagram of a rotor containing a T-shaped main magnet.

Rare earth NdFeB layer 1, auxiliary magnet 2, non-rare earth material layer 3, rotor core 4, rotating shaft 5, stator 6, winding 7.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model. It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

Specific Embodiment 1: This embodiment is described in detail with reference to FIGS. 2 to 4. A Halbach permanent magnet synchronous motor rotor with rare earth combined magnetic poles described in this embodiment includes a permanent magnet and a rotor core 4. The permanent magnet It is arranged on the outer circumferential surface of the rotor core 4 in a Halbach array structure.

As shown in Figures 2 and 3, the number of pole pairs of the rotor in this embodiment is 2, and each pole permanent magnet includes 1 main magnet and 2 auxiliary magnets 2, and the 2 auxiliary magnets 2 are respectively located on the two circumferential sides of the main magnet. side. The main magnet in each pole includes a non-rare earth material layer 3 and a rare earth NdFeB layer 1 sequentially arranged radially from inside to outside. Both the auxiliary magnet 2 and the non-rare earth material layer 3 are non-rare earth ferrite.

The magnetization direction of the main magnet is parallel to the radial center line of the main magnet, and the magnetization direction of the main magnet in two adjacent poles is opposite.

满足下式：As shown in Figure 4(a), when the radial centerline of the main magnet in any pole is taken as the reference line, and the magnetization direction of the main magnet is toward the center of the rotor core 4, the charge of the ith auxiliary magnet 2 magnetic angle

Satisfies the following formula:

满足下式：As shown in Figure 4(b), when taking the radial midline of the main magnet in any pole as the reference line and the magnetization direction of the main magnet facing away from the center of the rotor core 4, the i-th auxiliary magnet 2 Magnetization angle

Satisfies the following formula:

为第i块辅助磁体2充磁方向与基准线的夹角，且位于基准线顺时针方向的夹角角度为负值，位于基准线逆时针方向的夹角角度为正值。Wherein, p=2 is the number of pole pairs of the motor, i=1,2,...,8, θ _i is the angle between the radial center line of the i-th auxiliary magnet 2 and the reference line, and the magnetization angle

is the angle between the magnetization direction of the i-th auxiliary magnet 2 and the reference line, and the included angle in the clockwise direction of the reference line is a negative value, and the included angle in the counterclockwise direction of the reference line is a positive value.

Specific embodiment two: this embodiment is described in detail with reference to Fig. 5, the difference between this embodiment and the Halbach permanent magnet synchronous motor rotor of a kind of rare earth combined magnetic pole described in specific embodiment one is that in this embodiment, each pole The permanent magnets each include 2 main magnets and 2 auxiliary magnets 2 .

The increase in the number of permanent magnet blocks is beneficial to improve the electromagnetic torque of the motor.

Specific embodiment three: this embodiment is described in detail with reference to Fig. 6, the difference between this embodiment and the Halbach permanent magnet synchronous motor rotor of a kind of rare earth combined magnetic pole described in specific embodiment one is that in this embodiment, each pole The permanent magnets all include 1 main magnet and 4 auxiliary magnets 2 .

The increase in the number of permanent magnet blocks is beneficial to improve the electromagnetic torque of the motor.

Specific embodiment four: this embodiment is specifically described with reference to Fig. 7, and this embodiment is the further description of the Halbach permanent magnet synchronous motor rotor of a kind of few rare earth combined magnetic pole described in specific embodiment one, and in this embodiment, the main magnet It is different from the thickness of the auxiliary magnet 2 in the radial direction, that is, the radial thickness of the main magnet is greater than or smaller than the radial thickness of the auxiliary magnet 2 .

In this embodiment, the magnetic poles combined with unequal thickness can reduce the amount of non-rare earth permanent magnets, further reduce the mass of the rotor, and help reduce the cost of the motor. At the same time, the unequal-thickness combined magnetic pole Halbach array is more conducive to adjusting the sine degree of the air-gap magnetic flux density waveform and is conducive to reducing torque ripple.

Specific embodiment five: this embodiment is a further description of the Halbach permanent magnet synchronous motor rotor of a kind of rare earth combined magnetic pole described in specific embodiment one. In this embodiment, the overall arc length and arc length of the main magnet in each pole are The arc lengths of each auxiliary magnet 2 are equal or different, and when they are not equal, the overall arc length of the m main magnets in each pole is greater than or smaller than the arc length of each auxiliary magnet 2 .

In this embodiment, the width of the main magnet is different from the arc length (width) of the auxiliary magnet 2, so that the design is more flexible. According to the design target of the air gap magnetic flux density, the ratio of the permanent magnet required for the torque of the rare earth permanent magnet synchronous motor can be adjusted. width. The larger the width of the main magnet, the more beneficial it is to improve the electromagnetic torque of the motor, and at the same time it will also increase the amount of rare earth permanent magnets and increase the cost of the motor.

Specific embodiment five: this embodiment is specifically described with reference to Fig. 8, and this embodiment is the further explanation to the Halbach permanent magnet synchronous motor rotor of a kind of few rare earth combined magnetic pole described in specific embodiment one, in this embodiment, rare earth neodymium The shape of the iron-boron layer 1 is similar to a "T" shape. Specifically, the rare earth NdFeB layer 1 includes radially arranged outer arcs and inner arcs, and the arc length of the outer arc is longer than that of the inner arc. long.

In this embodiment, the permanent magnet of the motor at the radial centerline position of the rare earth NdFeB layer 1 provides the most magnetic flux, and the T-shaped rare earth NdFeB layer 1 part expands to the permanent magnet at the radial position corresponding to the auxiliary magnet. The magnetic flux provided by the magnet is next, and the radial position of the T-shaped extension part provides the least magnetic flux by the permanent magnet of the motor. It is beneficial to the sinusoidal distribution of the air gap magnetic flux density waveform and reduces torque ripple.

Because NdFeB is relatively brittle, too thin and easy to break, and the thickness of the permanent magnet of the rare earth permanent magnet synchronous motor is thin, the torque performance drops rapidly. Therefore, if the rare earth Halbach motor reduces the thickness of the rare earth material permanent magnet, the degree of material used is very limited. . Therefore, it is very limited to rely on reducing the thickness of the rare earth permanent magnet a little bit. And the utility model adopts ferrite in the combined magnetic pole, although the thickness of the rare earth permanent magnet and the rare earth permanent magnet in the common rare earth permanent magnet synchronous motor have little difference, the width is far smaller than the common rare earth permanent magnet synchronous motor, which can obviously Reduce the amount of rare earth materials used.

If it is a structure with a built-in permanent magnet, the problem of demagnetization of the permanent magnet is more prominent in the field weakening control. Since this embodiment belongs to the category of surface-mounted type, the orthogonal axis inductance is equal, and the id=0 control is adopted, and there is no demagnetization current. In this case, the disadvantage of ferrite with low performance and easy demagnetization is not obvious. Because there is no need for field weakening, the problem of demagnetization is not prominent.

To sum up, the existing rare earth Halbach focuses on improving the electromagnetic torque performance of the motor, and tends to use a large amount of NdFeB materials with better magnetic properties. However, the utility model can increase the electromagnetic torque while reducing the amount of rare earth materials, and has good application prospects.

Although the invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It is therefore to be understood that numerous modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the invention as defined by the appended claims. It shall be understood that different dependent claims and features described herein may be combined in a different way than that described in the original claims. It will also be appreciated that features described in connection with individual embodiments can be used in other described embodiments.

Claims (5)

1. A Halbach permanent magnet synchronous motor rotor with few rare earth combined magnetic poles comprises a permanent magnet and a rotor core (4), wherein the permanent magnet is arranged on the outer circumferential surface of the rotor core (4) in a Halbach array structure,

it is characterized in that each pole permanent magnet comprises m main magnets and 2n auxiliary magnets (2), wherein m and n are positive integers, n auxiliary magnets (2) are respectively arranged on two sides of the circumference of the m main magnets, each main magnet comprises a non-rare-earth material layer (3) and a rare-earth neodymium-iron-boron layer (1) which are sequentially arranged from inside to outside along the radial direction, the auxiliary magnets (2) and the non-rare-earth material layers (3) are non-rare-earth ferrite,

the magnetizing directions of the m main magnets in the same pole are the same and are parallel to the radial central line of the whole m main magnets, the magnetizing directions of the main magnets in the adjacent two poles are opposite,

when the radial central line of the whole m main magnets in any pole is taken as a datum line and the magnetizing direction of the m main magnets is away from the circle center of the rotor core (4), the magnetizing angle theta of the ith auxiliary magnet (2) _i ^* Satisfies the following formula:

when the radial central line of the whole m main magnets in any pole is taken as a datum line and the magnetizing direction of the m main magnetic poles faces the circle center of the rotor core (4), the magnetizing angle theta of the ith auxiliary magnet (2) _i ^* Satisfies the following formula:

wherein the method comprises the steps ofP=2 is the pole pair number of the motor, i=1, 2,..4 pn, 3.ltoreq.m+2n.ltoreq.6, θ _i Is the included angle between the radial center line of the ith auxiliary magnet (2) and the datum line, and the magnetizing angle theta _i ^* The included angle between the magnetizing direction of the ith auxiliary magnet (2) and the datum line is negative, and the included angle between the magnetizing direction and the datum line in the clockwise direction is positive.

2. Halbach permanent magnet synchronous motor rotor with few rare earth combined poles according to claim 1, characterized in that the overall arc length of m main magnets in each pole is equal to the arc length of each auxiliary magnet (2).

3. Halbach permanent magnet synchronous motor rotor with few rare earth combined poles according to claim 1, characterized in that the overall arc length of m main magnets in each pole is larger than the arc length of each auxiliary magnet (2).

4. Halbach permanent magnet synchronous motor rotor with few rare earth combined poles according to claim 1, characterized in that the overall arc length of m main magnets in each pole is smaller than the arc length of each auxiliary magnet (2).

5. A Halbach permanent magnet synchronous motor rotor with few rare earth combined magnetic poles according to claim 1, characterized in that the rare earth neodymium iron boron layer (1) comprises an outer layer arc and an inner layer arc which are radially arranged, wherein the arc length of the outer layer arc is larger than that of the inner layer arc.

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