WO2024082799A1

WO2024082799A1 - Motor, compressor, and refrigeration device

Info

Publication number: WO2024082799A1
Application number: PCT/CN2023/113570
Authority: WO
Inventors: 张德金; 姚俊; 邱小华; 盖蕊
Original assignee: 广东美芝制冷设备有限公司
Priority date: 2022-10-21
Filing date: 2023-08-17
Publication date: 2024-04-25
Also published as: CN117955275A

Abstract

The present application discloses a motor, a compressor, and a refrigeration device. The motor comprises a stator (110) and a rotor (120). Permanent magnets (123) in the rotor (120) are cerium-containing permanent magnets, the stator (110) comprises a stator core, the stator core has Q stator teeth (111), the length of the stator core is L, and the outer diameter of the stator (110) is D. The motor satisfies: 6*Q*L/D≥x, wherein x% is the mass percentage of cerium contained in each permanent magnet (123).

Description

Motors, compressors and refrigeration equipment

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese patent application No. 202211297340.6, filed on October 21, 2022, and entitled “Motors, Compressors and Refrigeration Equipment,” the entire contents of which are incorporated by reference into this application.

Technical Field

The present application belongs to the field of motor technology, and specifically relates to a motor, a compressor and a refrigeration device.

Background technique

In the compressor field of household appliances such as air conditioners and refrigerators, variable frequency motors have become the mainstream. The permanent magnets of variable frequency motors are mostly neodymium iron boron permanent magnets, which generally contain a considerable amount of precious rare earth elements such as praseodymium and neodymium. With the sharp increase in the price of such rare earth materials, the cost of neodymium iron boron permanent magnets and motors has risen accordingly.

Using cerium-containing permanent magnets to replace conventional NdFeB permanent magnets is a means of reducing costs. Cerium, as the most abundant rare earth element, costs only a few tens of times less than NdPr. Replacing part of NdPr with cerium can reduce the cost of permanent magnets. However, after the introduction of cerium, the content of NdPr is reduced, the coercive force of the permanent magnet decreases, and the performance of the motor is affected.

Therefore, how to reduce the cost of permanent magnets while taking into account motor performance is an urgent problem that needs to be solved.

Summary of the invention

The present application aims to at least partially solve one of the above technical problems existing in the prior art. To this end, the present application provides a motor, a compressor including the motor, and a refrigeration device including the motor or the compressor.

The motor according to the first aspect of the present application comprises:

A stator, wherein the stator comprises a stator core, the stator core has Q stator teeth, the length of the stator core is L, and the outer diameter of the stator is D;

A rotor, comprising a rotor core and a plurality of permanent magnets disposed on the rotor core, wherein the permanent magnets contain cerium;

The motor satisfies: 6*Q*L/D≥x, wherein x% is the mass percentage of cerium contained in the permanent magnet.

According to some embodiments of the present application, the cerium content x% in the permanent magnet satisfies: 0＜x%≤10%.

According to some embodiments of the present application, the cerium content x% in the permanent magnet satisfies: 0＜x%≤6%.

According to some embodiments of the present application, the cerium content x% in the permanent magnet satisfies: 3%≤x%≤10%.

According to some embodiments of the present application, the cerium content x% in the permanent magnet satisfies: 3%≤x%≤6%.

According to some embodiments of the present application, a stator winding is wound around the stator teeth.

According to some embodiments of the present application, concentrated windings are wound around the stator teeth.

According to some embodiments of the present application, the number Q of the stator teeth satisfies: Q≥12.

According to some embodiments of the present application, a plurality of stator slots are provided on the stator core.

Generally, a stator slot is formed by two adjacent stator teeth, so the number of the stator slots is equal to the number Q of the stator teeth.

According to some embodiments of the present application, the number of the stator slots is ≥12.

According to some embodiments of the present application, the number of the stator slots is 12 or 15.

According to some embodiments of the present application, the number of magnetic poles of the rotor is ≥8.

According to some embodiments of the present application, the number of magnetic poles of the rotor is 8 to 16. For example, the number of magnetic poles of the rotor may be 8, 10, 14 or 16.

According to some embodiments of the present application, when the number of the stator slots is 12, the number of magnetic poles of the rotor is 8, 10 or 14.

According to some embodiments of the present application, when the number of the stator slots is 15, the number of magnetic poles of the rotor is 10, 14 or 16.

The number of rotor magnetic poles and the number of stator slots of the permanent magnet motor can be combined in many ways, and are not limited to the combinations listed above. In general, as the number of stator slots increases, the maximum number of magnetic poles that can be matched can be appropriately increased.

According to some embodiments of the present application, the outer diameter D of the stator satisfies: 80 mm ≤ D ≤ 130 mm.

According to some embodiments of the present application, the motor further satisfies: Q*b _t /(P*b _m )≤1.36-x/100, and 5*Q*b _t /(4*P*b _m )≥1.36-x/100, wherein b _t is the width of the stator teeth, P is the number of pole pairs of the rotor, and b _m is the width of the permanent magnet per pole.

According to some embodiments of the present application, the width b _t of the stator teeth satisfies: 5 mm ≤ _{b t} ≤ 9 mm.

According to some embodiments of the present application, the width b _m of each pole permanent magnet satisfies: 15 mm ≤ b _m ≤ 21 mm.

According to some embodiments of the present application, the pole pair number P of the rotor is ≥4.

According to some embodiments of the present application, the number of pole pairs of the rotor is 4 to 8. For example, the number of pole pairs of the rotor may be 4, 5, 7 or 8.

According to some embodiments of the present application, the length L of the stator core satisfies: 20 mm ≤ L ≤ 50 mm.

According to some embodiments of the present application, the length L of the stator core satisfies: 30 mm ≤ L ≤ 40 mm. As an example, the length L of the stator core may be 30 mm or 35 mm.

According to some embodiments of the present application, a plurality of rotor slots are provided on the rotor core, and a plurality of permanent magnets are respectively disposed in the plurality of rotor slots.

One or more permanent magnets can be arranged in the rotor slot. All permanent magnets in the same rotor slot constitute a magnetic Therefore, when one permanent magnet is arranged in the rotor slot, the width of the permanent magnet of the pole is the width of the one permanent magnet; when more than two permanent magnets are arranged in the rotor slot, the width of the permanent magnet of the pole is the total width of the more than two permanent magnets.

According to some embodiments of the present application, the rotor slot is V-shaped.

According to some embodiments of the present application, the rotor slot is V-shaped, and every two permanent magnets are symmetrically arranged on both sides of the V-shaped rotor slot.

According to some embodiments of the present application, the V-shaped opening faces the outside of the rotor.

According to some embodiments of the present application, the thickness of the permanent magnet is 1.5 mm-2.5 mm.

Increasing the thickness of the permanent magnet can increase the remanence, but it will also increase the cost of the permanent magnet. Controlling the thickness of the permanent magnet within the above range can better balance the cost and anti-demagnetization performance.

According to some embodiments of the present application, the thickness of the permanent magnet is 1.5 mm-2.0 mm.

According to some embodiments of the present application, the thickness of the permanent magnet is 1.5 mm-1.8 mm.

As an example, the thickness of the permanent magnet may be approximately 1.5 mm, 1.6 mm, 1.7 mm or 1.8 mm.

According to some embodiments of the present application, the permanent magnet contains praseodymium and neodymium, wherein the total mass percentage of praseodymium and neodymium is 20%-32%.

According to some embodiments of the present application, in the permanent magnet, the total mass percentage of praseodymium and neodymium is 25%-32%.

According to some embodiments of the present application, the permanent magnet contains dysprosium and/or terbium, wherein the total mass percentage of dysprosium and terbium is ≤3%.

According to some embodiments of the present application, the permanent magnet further contains cobalt, wherein the mass percentage of cobalt is ≤2%.

According to some embodiments of the present application, the mass percentage of cobalt in the permanent magnet is 1%-2%.

According to some embodiments of the present application, the permanent magnet also contains trace amounts of other elements, which may be manganese, copper, gallium, terbium, niobium, etc., to improve the comprehensive performance of the permanent magnet, such as operating temperature and stability.

According to some embodiments of the present application, the total mass percentage of the other elements is ≤2%.

According to some embodiments of the present application, the permanent magnet mainly comprises, by mass percentage:

The total amount of praseodymium and neodymium is 20%-32%, cerium is 3%-10%, the total amount of dysprosium and terbium is 0-3%, cobalt is 1%-2%, and the remaining main component is iron.

According to some embodiments of the present application, the intrinsic coercive force H _cJ of the permanent magnet is ≥1500KA/m.

According to some embodiments of the present application, the intrinsic coercive force H _cJ of the permanent magnet is: 1500KA/m≤H _cJ ≤2000KA/m.

A compressor according to a second aspect of the present application includes the motor described above.

The refrigeration device according to the third aspect of the present application includes the motor or the compressor described above.

According to some embodiments of the present application, the refrigeration equipment includes an air conditioner, a refrigerator or a freezer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the structure of a motor according to an embodiment of the present application.

Reference numerals:
stator 110, stator teeth 111, stator slots 112, stator yoke 113;
Rotor 120, rotor core 121, rotor slot 122, permanent magnet 123;
Air gap 130.

Detailed ways

The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same reference numerals throughout represent the same elements or elements with the same functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

In the description of the present application, descriptions of orientations, such as up, down, etc., or orientations or positional relationships indicated are based on the orientations or positional relationships shown in the drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

In the description of the present application, a number refers to one or more, a plurality refers to more than two, and “above” includes the number itself.

As one of the three key materials of permanent magnet motors, NdFeB permanent magnets are composed of about 60% iron, and the remaining main elements are rare earth elements such as praseodymium and neodymium. Affected by the rising prices of such rare earth materials, the price of NdFeB permanent magnets has continued to rise, resulting in a significant increase in the proportion of NdFeB permanent magnet costs in the total cost of motors. Therefore, reducing the cost of permanent magnets is one of the effective ways to reduce the cost of motors.

To this end, an embodiment of the present application provides a motor, which can reduce the proportion of praseodymium and neodymium elements in the permanent magnet and ensure the coercive force of the permanent magnet by using cerium-containing permanent magnets and performing structural design on the motor, thereby taking into account both electrode cost and reliability.

1 , in one embodiment of the present application, the motor includes a stator 110 and a rotor 120. The stator 110 includes a stator core having Q stator teeth 111; the rotor 120 includes a rotor core 121 and a plurality of permanent magnets 123, wherein the permanent magnets 123 contain cerium.

The motor satisfies the following relationship: 6*Q*L/D≥x; L is the length of the stator core, D is the outer diameter of the stator 110 , and x% is the mass percentage of cerium contained in the permanent magnet 123 .

In this embodiment, the use of cerium-containing permanent magnets 123 as magnetic poles can reduce the praseodymium-neodymium element content in the permanent magnets, reduce the cost of permanent magnets, and reduce the cost pressure caused by the rising price of praseodymium-neodymium rare earth materials. However, the presence of cerium in the permanent magnet 123 will cause the coercive force to decrease, affect the demagnetization resistance, and thus reduce the efficiency of the motor. In order to compensate for the coercive force loss of the cerium-containing permanent magnet, the present application designs the size of the motor, and constrains the relationship between the number Q of the stator teeth 111, the outer diameter D of the stator 110, and the length L of the stator core according to the mass percentage x% of cerium in the permanent magnet 123, so that it satisfies the following relationship 6*Q*L/D≥x. According to the specific motor size design, the loss of the coercive force of the permanent magnet 123 caused by cerium doping can be compensated by the motor size design, ensuring that the coercive force of the permanent magnet 123 after cerium doping still meets the use requirements, thereby taking into account the cost and efficiency of the motor.

Specifically, the greater the length L of the stator core, or the greater the number of stator teeth 111 (i.e., stator slots 112), the fewer the number of winding turns can be, and the demagnetization resistance of the motor can be enhanced. Therefore, the motor can be optimized in size as follows: the number of stator teeth 111 and/or the length of the stator core can be increased to improve the demagnetization resistance of the motor, thereby using permanent magnets 123 with a higher cerium content and reducing the content of praseodymium and neodymium elements in the permanent magnets 123, thereby achieving a better purpose of reducing costs and increasing efficiency.

Table 1 shows the minimum stator core length _Lmin adapted to the stator outer diameter _D0 of the existing motor products, and the calculation results corresponding to the formula 6*Q* _Lmin / _D0 under different numbers of stator slots Q, that is, when the constraints of the present application are met, the corresponding maximum cerium content in the permanent magnet is recorded as _xmax %. It should be noted that when _xmax is a decimal, it refers to the value of directly omitting the third decimal place and the subsequent decimal places of the calculation result, not the value after rounding. It can be seen that as the number of stator slots increases, permanent magnets containing more cerium elements can be used.

Table 1 Correspondence between stator outer diameter, minimum stator core length, number of stator slots and their maximum value of x

As an embodiment, the cerium content x% in the permanent magnet 123 satisfies: 0<x%≤10%. As a more preferred embodiment, the mass percentage x% of cerium in the permanent magnet 123 satisfies: 0<x%≤6%.

As the cerium content increases, the coercive force of the permanent magnet decreases, affecting the anti-demagnetization ability and motor efficiency. Controlling the cerium content in the permanent magnet 123 to not exceed 10% can obtain better anti-demagnetization performance and improve motor efficiency.

As an embodiment, the cerium content x% in the permanent magnet 123 satisfies: 3%≤x%≤10%. As a more preferred embodiment, the cerium content % in the permanent magnet 123 satisfies: 3%≤x%≤6%.

If the cerium content is too low, the degree of replacement of praseodymium and neodymium is limited, which limits the extent of cost reduction. When the cerium content is in the range of 3%-6%, the motor performance is optimal and the cost reduction effect is obvious.

It can be understood that in the motor, the rotor 120 is configured to be rotatable relative to the stator 110 . As shown in FIG. 1 , the stator 110 is provided with an inner cavity, and the rotor 120 is rotatably disposed in the inner cavity of the stator 110 .

As an implementation manner, a stator winding (not shown) is wound on the stator teeth 111 .

The stator windings of permanent magnet synchronous motors are divided into two types: distributed and centralized. Among them, the end height of the centralized winding is small and the cost is low; the end height of the distributed winding is relatively large, the cost is higher, but the motor running noise is smaller.

As an implementation mode, a concentrated winding is wound on the stator teeth 111. For a salient pole stator, the concentrated winding is usually wound into a rectangular coil.

As an implementation mode, the number of stator teeth 111 satisfies: Q ≥ 12, that is, the number of stator slots 112 defined by the stator teeth 111 is ≥ 12. As the number of stator teeth 111 increases, the number of stator slots 112 increases, the number of winding turns decreases, and the demagnetization resistance of the motor is enhanced, so the requirement for the coercive force of the permanent magnet is relatively low, and the permanent magnet 123 with a higher cerium content can be used while ensuring the motor performance.

As an implementation manner, the number of the stator slots 112 is 12 or 15.

As an implementation manner, the number of magnetic poles of the rotor 120 is ≥ 8. For example, the number of magnetic poles of the rotor 120 may be 8-16, and more specifically, the number of magnetic poles of the rotor 120 may be 8, 10, 14 or 16.

As an implementation manner, the number of the stator slots 112 is 12, and the number of magnetic poles of the rotor 120 matching therewith is 8, 10 or 14.

As an implementation method, the number of stator slots 112 is 15, and the number of magnetic poles of the rotor 120 matched therewith is 10. 14 or 16.

There can be multiple combinations of the number of magnetic poles of the rotor 120 of the permanent magnet motor and the number of stator slots 112, which are not limited to the above-mentioned combinations. For example, when the number of stator slots 112 is 12, the number of magnetic poles of the rotor 120 can be 8, 10 or 14. In general, as the number of stator slots 112 increases, the maximum number of magnetic poles can be appropriately increased.

As an implementation method, the outer diameter of the stator 110 is: 80mm≤D≤130mm. As the outer diameter of the stator 110 increases, the anti-demagnetization capability of the motor is enhanced, but the cost will also increase. Controlling the outer diameter of the stator 110 within the above range can meet the use requirements of most household compressor motors.

As an implementation manner, the length L of the stator core satisfies: 20 mm ≤ L ≤ 50 mm.

Within the above-mentioned length range of the stator core, the use requirements of general compressor motors can be met and the cost is the lowest.

As an implementation manner, the length L of the stator core satisfies: 30 mm ≤ L ≤ 40 mm. For example, the length L of the stator core may be 30 mm or 35 mm.

As an implementation manner, a plurality of rotor slots 122 are provided on the rotor core 121 , and the plurality of permanent magnets 123 are respectively disposed in the plurality of rotor slots 122 .

It can be understood that one or more permanent magnets 123 can be arranged in each rotor slot 122, and all permanent magnets 123 in the same rotor slot 122 constitute a magnetic pole. Therefore, when one permanent magnet 123 is arranged in the rotor slot 122, the width of the permanent magnet of the pole is the width of the one permanent magnet 123; when more than two permanent magnets 123 are arranged in the rotor slot 122, the width of the permanent magnet of the pole is the total width of the more than two permanent magnets 123.

To improve the motor performance, more than two permanent magnets 123 may be provided in each rotor slot 122 to reduce the magnetic flux density of the stator teeth 111 , reduce iron loss, and increase the motor's anti-demagnetization capability.

As an implementation method, the rotor slot 122 is V-shaped, and every two permanent magnets 123 are symmetrically arranged on both sides of the V-shaped slot to form a magnetic pole. The permanent magnets 123 are symmetrically distributed in the V-shaped rotor slot 122, which can increase the magnetic pole width, reduce iron loss, and enhance the anti-demagnetization capability.

As an implementation manner, the V-shaped opening faces the outside of the rotor 120 .

1 , in one embodiment, the rotor slot 122 is a V-shaped structure with an opening facing outward, the number of the rotor slots 122 is 8, the number of the permanent magnets 123 is 16, and every two permanent magnets 123 are symmetrically arranged on both sides of the V-shaped slot to form a magnetic pole.

As an implementation mode, the motor further satisfies: Q*b _t /(P*b _m )≤1.36-x/100, and 5*Q*b _t /(4*P*b _m )≥1.36-x/100, wherein b _t is the width of the stator tooth 111, P is the number of pole pairs of the rotor 120, and b _m is the width of the permanent magnet per pole, and b _t and b _m are shown in FIG1. When the above conditions are met, the motor efficiency can be improved while reducing the cost.

The magnetic flux generated by the permanent magnet 123 passes through the air gap 130, the stator tooth 111, the stator yoke 113 and then returns to the stator tooth 111, the air gap 130 and the permanent magnet 123 to form a closed magnetic field line. If the width b _t of the stator tooth 111 is too large, the tooth magnetic flux density will be If the width b _t of the stator tooth 111 is too small, the magnetic density of the tooth will be too high, resulting in a significant increase in the iron loss of the motor, which will reduce the efficiency of the motor.

As an implementation manner, the width b _t of the stator tooth 111 satisfies: 5 mm ≤ _{b t} ≤ 9 mm.

When the width of the stator tooth 111 increases, the area of the stator slot 112 decreases. Under the same number of winding turns, the diameter of the copper wire decreases and the copper loss increases. When the width of the stator tooth 111 decreases, the magnetic flux density of the stator tooth increases and the iron loss of the motor increases. Within the above-mentioned stator tooth width range, the balance between iron loss and copper loss can be taken into account, thereby improving the motor efficiency.

As an implementation manner, the width b _m of each pole permanent magnet satisfies: 15 mm ≤ b _m ≤ 21 mm.

The width of each permanent magnet is positively correlated with the excitation magnetic field of the motor. If the width of each permanent magnet is too large, the increase in motor efficiency is not obvious. If the width of each permanent magnet is too small, the motor operating current increases and the loss increases under the same load, affecting the motor efficiency.

As an implementation manner, the number of pole pairs P of the rotor 120 is ≥ 4. For example, the number of pole pairs of the rotor 120 may be 4-8, and more specifically, the number of pole pairs of the rotor 120 may be 4, 5, 7 or 8.

As an implementation, the thickness of the permanent magnet 123 is 1.5 mm to 2.5 mm, further 1.5 mm to 2.0 mm, and further 1.5 mm to 1.8 mm.

Increasing the thickness of the permanent magnet 123 can improve the residual magnetism, but it will also increase the cost of the permanent magnet 123. Controlling the thickness of the permanent magnet 123 within the above range can better balance the motor cost and anti-demagnetization performance.

As an implementation, the thickness of the permanent magnet 123 may be approximately 1.5 mm, 1.6 mm, 1.7 mm, or 1.8 mm.

As an implementation manner, the permanent magnet 123 contains praseodymium and neodymium, and the total mass percentage of praseodymium and neodymium is 20%-32%.

According to the x% cerium content in the permanent magnet 123, the total content of praseodymium and neodymium can be reduced by x% accordingly.

As an embodiment, the total mass percentage of praseodymium and neodymium in the permanent magnet 123 is 25%-32%.

As an implementation manner, the permanent magnet 123 further contains dysprosium and/or terbium, and the total mass percentage of dysprosium and terbium is ≤3%.

As an implementation manner, the permanent magnet 123 also contains cobalt, and the mass percentage of cobalt is 1%-2%.

The permanent magnet 123 contains an element selected from dysprosium, terbium, and cobalt, and can increase the coercive force.

As an implementation mode, the permanent magnet 123 also contains trace amounts of other elements, which are selected from manganese, copper, gallium, terbium, niobium, etc., for improving the comprehensive performance of the permanent magnet, such as operating temperature and stability.

As an embodiment, the total mass percentage of the other elements is ≤2%.

As an implementation mode, the permanent magnet 123 has the following composition by mass percentage: 20%-32% total amount of praseodymium and neodymium, 3%-10% cerium, 0-3% dysprosium, 1%-2% cobalt, and the remaining main component is iron.

The permanent magnet 123 mentioned above can be purchased from the market, or prepared by a method known to a person skilled in the art, and will not be described in detail.

The present application is further described below through exemplary embodiments.

Example 1

The motor of this embodiment, as shown in FIG. 1 , includes a stator 110 and a rotor 120 .

The stator core has Q stator teeth 111 and Q stator slots 112, where Q=12. The length of the stator core is L=35 mm, the outer diameter of the stator 110 is D=101 mm, and the width of the stator tooth 111 is b _t =6.5 mm. A concentrated winding (not shown) is wound around each stator tooth 111. The model of the stator 110 is 12C, and the wire diameter*number of turns=0.55×140, where the wire diameter refers to the diameter of the bare copper wire of the winding, in mm.

The rotor 120 includes a rotor core 121 and 16 permanent magnets 123. The rotor core 121 is evenly provided with 8 V-shaped rotor slots 122 along the circumference of its cross section, with the V-shaped opening facing outward. Every two permanent magnets 123 are symmetrically distributed on both sides of a V-shaped slot to form a magnetic pole. There are 8 magnetic poles in total, and the number of pole pairs P = 4. The size of each permanent magnet 123 is: length × width × thickness = 30 mm × 8.4 mm × 1.6 mm, wherein the width of the permanent magnet 123 b _m /2 = 8.4, corresponding to the width of each permanent magnet b _m = 16.8.

The permanent magnet 123 is commercially available, model: 42SHC. The permanent magnet 123 mainly comprises (by mass fraction): praseodymium-neodymium total amount 25%, cerium x%=5%, dysprosium 2.25%, cobalt 1-2%, and the rest mainly iron, and trace amounts of manganese, copper, gallium, niobium, aluminum and other elements.

The motor satisfies: 6*Q*L/D=6*12*35/101=24.95≥x=5.

The motor also satisfies: Q*b _t /(P*b _m )=12*6.5/(4*16.8)=1.16≤1.36-x/100=1.36-5/100=1.31.

The motor also satisfies: 5*Q*b _t /(4*P*b _m )=5*12*6.5/(4*4*16.)=1.45≥1.36-x/100=1.36-5/100=1.31.

Example 2

Compared with Example 1, the difference is that in the permanent magnet 123, the cerium content is 2.5%, the total amount of praseodymium and neodymium is 27.5%, and the rest remains unchanged.

Comparative Example 1

Compared with the embodiment 1, the difference is that in the permanent magnet 123, the total amount of praseodymium and neodymium is 30%, cerium is 0%, and the rest remains unchanged.

The motor parameters of Example 1, Example 2 and Comparative Example 1 are shown in Table 2.

Table 2 Motor parameters

Test Case

This test example tests the motor performance of Examples 1, 2 and Comparative Examples 1-3.

Among them, the anti-demagnetization performance test process is as follows:

(1) Test the magnetic flux at room temperature;

(2) placing the motor in a high temperature environment of 130° C. for more than 4 hours, then passing a DC demagnetization current through the motor, and rotating the rotor 120 times during the current passing process;

(3) Place the device at room temperature for more than 4 hours, test the magnetic flux after demagnetization, compare it with that before demagnetization, and calculate the demagnetization rate.

The anti-demagnetization performance test results are shown in Table 3.

Table 3 Anti-demagnetization performance of motor under different test conditions

The test results of permanent magnet coercivity and motor efficiency are shown in Table 4.

Table 4 Permanent magnet coercivity and motor efficiency

It can be seen from Table 3 and Table 4 that as the cerium content increases from 2.5% to 5%, demagnetization increases, and coercivity and intrinsic coercivity decrease. In order to ensure the stable operation of the motor during its life cycle, the demagnetization rate of the permanent magnet generally does not exceed 3%. It can be seen that at the maximum operating current of 26A, the motor can meet the anti-demagnetization reliability requirements during the product life cycle. At the same time, the efficiency of the motor containing cerium permanent magnets is equivalent to that of conventional NdFeB permanent magnets, ensuring the energy efficiency level of the product.

In terms of cost, taking Example 1 as an example, according to the current price of rare earth bulk materials, the gram weight unit price of conventional praseodymium-neodymium permanent magnet 42SH is 0.38 yuan/gram, and the gram weight unit price of cerium (5wt%) permanent magnet 42SHC is 0.279 yuan/gram. The weight of each permanent magnet 123 is about 3.1g, and there are 16 pieces in a motor. This application uses cerium-doped permanent magnets 123 to replace traditional neodymium iron boron permanent magnets, so the material cost of each motor can be reduced by about 5 yuan, and the cost reduction of permanent magnet 123 is 26.58%. (((0.38-0.279)/0.38)*100%), the cost reduction effect is significant.

As another embodiment of the present application, a compressor is provided, which includes the motor of the above embodiment.

It can be understood that the compressor of this embodiment, since it uses the motor of the above embodiment, has at least all the beneficial effects brought about by the technical solution of the above motor.

Specifically, the compressor of this embodiment includes the motor of the above embodiment, and the motor includes a stator 110 and a rotor 120. The stator 110 includes a stator core, the stator core has Q stator teeth, the length of the stator core is L, and the outer diameter of the stator 110 is D; the rotor 120 includes a rotor core 121 and a plurality of permanent magnets 123 arranged on the rotor core 121, and the permanent magnets 123 contain cerium; the motor satisfies: 6*Q*L/D≥x, wherein x% is the mass percentage of cerium contained in the permanent magnets 123.

This embodiment uses a cerium-containing permanent magnet 123 as the magnetic pole of the rotor 120, and by constraining the number Q of stator teeth 111, the outer diameter D of the stator 110, the length L of the stator core 121 and the mass percentage x% of cerium in the permanent magnet 123, the following relationship 6*Q*L/D≥x is satisfied. According to the specific motor size design, the loss of the coercive force of the permanent magnet 123 caused by cerium doping can be compensated by the motor size design, thereby ensuring the coercive force of the permanent magnet 123, taking into account the cost and efficiency of the motor. Specifically, the larger the length L of the stator core, or the more the number of stator teeth 111 (that is, the stator slots 112), the number of winding turns can be reduced accordingly, and the demagnetization resistance of the motor is enhanced. Therefore, the demagnetization resistance of the motor can be improved by increasing the number of stator teeth 111 and/or increasing the length of the stator core, so that the content of praseodymium and neodymium in the permanent magnet 123 can be reduced by using a permanent magnet 123 with a higher cerium content, thereby reducing the cost and ensuring the motor efficiency. As a result, the efficiency of the compressor can be guaranteed and the cost of the compressor can be reduced.

As another embodiment of the present application, a refrigeration device is provided, which includes the motor or the compressor of the above embodiment.

It can be understood that the refrigeration device of this embodiment, since it uses the motor or compressor of the above embodiments, has at least all the beneficial effects brought by the technical solutions of the above motor or compressor.

Further, the refrigeration equipment of this embodiment includes the compressor of the above embodiment, and the compressor includes the motor of the above embodiment, and the motor includes a stator 110 and a rotor 120. Among them, the stator 110 includes a stator core, the stator core has Q stator teeth, the length of the stator core is L, and the outer diameter of the stator 110 is D; the rotor 120 includes a rotor core 121 and a plurality of permanent magnets 123 arranged on the rotor core 121, and the permanent magnets 123 contain cerium; the motor satisfies: 6*Q*L/D≥x, wherein x% is the mass percentage of cerium contained in the permanent magnet 123.

In this embodiment, the cerium-containing permanent magnets 123 are used as the magnetic poles of the rotor 120. By constraining the number Q of the stator teeth 111, the outer diameter D of the stator 110, the length L of the stator core 121 and the mass percentage x% of cerium in the permanent magnets 123, the rotor 120 has a certain magnetic field. The relationship between them satisfies the following relationship 6*Q*L/D≥x. According to the specific motor size design, the loss of the coercive force of the permanent magnet 123 caused by cerium doping can be compensated by the motor size design, so that the coercive force of the permanent magnet 123 can be guaranteed, and the motor cost and efficiency are taken into account. Specifically, the larger the length L of the stator core, or the more the number of stator teeth 111 (that is, the stator slots 112), the number of winding turns can be reduced accordingly, and the demagnetization resistance of the motor is enhanced. Therefore, the demagnetization resistance of the motor can be improved by increasing the number of stator teeth 111 and/or increasing the length of the stator core, so that the content of praseodymium and neodymium elements in the permanent magnet 123 can be reduced by using a permanent magnet 123 with a higher cerium content, thereby reducing the cost while ensuring the motor efficiency. Finally, the efficiency of the refrigeration equipment can be guaranteed, while its cost is reduced.

As an implementation mode, the refrigeration equipment is an air conditioner.

As an implementation mode, the refrigeration device is a refrigerator or a freezer.

It is easy to understand that the above-mentioned air conditioner, refrigerator or freezer improves the overall cost performance by using the above-mentioned motor or compressor.

It should be noted that other components of the motor, compressor and refrigeration equipment in the embodiments of the present application are known to ordinary technicians in the field and will not be described in detail here.

Since the compressor or refrigeration equipment adopts all the technical solutions of the motor of the above embodiment, it at least has all the beneficial effects brought by the technical solutions of the above embodiment, which will not be repeated here.

The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

A motor, comprising:

A stator, the stator comprising a stator core, the stator core having Q stator teeth, the length of the stator core being L, and the outer diameter of the stator being D; and

A rotor, comprising a rotor core and a plurality of permanent magnets disposed on the rotor core, wherein the permanent magnets contain cerium;

The motor satisfies: 6*Q*L/D≥x, wherein x% is the mass percentage of cerium contained in the permanent magnet.
The motor according to claim 1, wherein the cerium content x% in the permanent magnet satisfies: 0＜x%≤10%.
The motor according to claim 1 or 2, wherein the cerium content x% in the permanent magnet satisfies: 3%≤x%≤10%.
The motor according to any one of claims 1 to 3, wherein the number Q of the stator teeth satisfies: Q ≥ 12.
The motor according to any one of claims 1 to 4, wherein an outer diameter D of the stator satisfies: 80 mm ≤ D ≤ 130 mm.
The motor according to any one of claims 1 to 5, wherein the motor further satisfies:

Q*b t /(P*b m )≤1.36-x/100, and 5*Q*b t /(4*P*b m )≥1.36-x/100;

Wherein, bt is the width of the stator teeth, P is the number of pole pairs of the rotor, and bm is the width of the permanent magnet per pole.
The motor according to any one of claims 1 to 6, wherein the number of magnetic poles of the rotor is ≥ 8.
The motor according to any one of claims 1 to 7, wherein the thickness of the permanent magnet is 1.5 mm-2.5 mm.
The motor according to any one of claims 1 to 8, wherein a length L of the stator core satisfies: 20 mm ≤ L ≤ 50 mm.
The motor according to any one of claims 1 to 9, wherein the permanent magnet contains praseodymium and neodymium, wherein the total mass percentage of praseodymium and neodymium is 20%-32%.
The motor according to any one of claims 1 to 10, wherein the permanent magnet contains dysprosium and/or terbium, wherein the total mass percentage of dysprosium and terbium is ≤3%.
The motor according to any one of claims 1 to 11, wherein the intrinsic coercive force H cJ of the permanent magnet is ≥1500 KA/m.
A compressor comprising the motor according to any one of claims 1 to 12.
A refrigeration device, comprising the motor according to any one of claims 1 to 12 or the compressor according to claim 13.