WO2024083076A1 - Permanent magnet motor, compressor and refrigerating device - Google Patents

Abstract

A permanent magnet motor, a compressor and a refrigerating device, the permanent magnet motor comprising a motor rotor (100) and a motor stator (200). The motor rotor (100) comprises a rotor core and multiple permanent magnets (120) provided on the rotor core, the number of poles 2P of the motor rotor (100) is greater than or equal to 8, the total width of each pole magnet is b_m, the permanent magnet (120) contains x% elemental cerium by mass, and b_m satisfies the following relation: b_m ≥ 2200/(150-x). The motor stator (200) comprises a stator core and a stator winding wound around the stator core, the stator core is located around the outside of the rotor core, the stator core is provided with a number Q of stator teeth (220) along an inner circumference, the tooth width of the stator teeth (220) is b_t, and the following relation is satisfied: Q×b_t/(P×b_m) ≤ 1.36-x/100 ≤ 5×Q×b _t/(4×P×b _m).

Description

Permanent magnet motors, compressors and refrigeration equipment

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese patent application number 202211296971.6, filed on October 21, 2022, and entitled “Permanent Magnet Motor, Compressor and Refrigeration Equipment”, and application number 202222818962.0, filed on October 21, 2022, and entitled “Permanent Magnet Motor, Compressor and Refrigeration Equipment”, the entire contents of which are incorporated by reference into this application.

Technical Field

The present application belongs to the technical field of compressors, and specifically relates to a permanent magnet motor, a compressor and a refrigeration device.

Background technique

At present, in the field of household air-conditioning compressors, fixed-speed models are gradually withdrawing from the market, and variable-frequency motors have become the mainstream technology. In order to adapt to the application environment of household air conditioners, the permanent magnets of variable-frequency motors are mostly _NdFeB permanent magnets containing heavy rare earth elements and high coercivity. NdFeB permanent magnets are permanent magnet materials based on the intermetallic compound _Nd2Fe14B , and the main components are neodymium, iron and boron. In order to obtain different properties, other rare earth metals such as dysprosium and praseodymium can be used to replace part of the neodymium in the permanent magnet. With the annual increase in the total number of variable-frequency models, the consumption of heavy rare earth elements (especially dysprosium and terbium) resources has also increased year by year. In order to reduce the use of heavy rare earth elements, new technologies need to be developed.

Compared with praseodymium and neodymium, cerium has obvious cost advantages, but compared with the same praseodymium and neodymium, the remanence of the corresponding rare earth magnet _Br will be reduced, which directly affects the performance of the motor. Therefore, in order to meet the application requirements of motor performance in the whole machine, it is necessary to improve the motor structure according to the content of rare earth element cerium in the permanent magnet.

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 permanent magnet motor, a compressor including the permanent magnet motor, and a refrigeration device including the compressor.

The permanent magnet motor provided according to the first aspect of the present application includes:

A motor rotor, comprising a rotor core and a plurality of permanent magnets disposed on the rotor core, wherein the number of poles of the motor rotor is 2P ≥ 8, the total width of each pole magnet is b _m , the permanent magnet contains a cerium element of x mass percent, and the relationship between b _m satisfies: b _m ≥ 2200/(150-x); and

The motor stator comprises a stator core and a stator winding wound on the stator core, wherein the stator core is arranged around the outer side of the rotor core, and the stator core is provided with Q stator teeth along the inner circumference, and the tooth width of the stator teeth is b _t , and the relationship satisfies: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ).

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

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

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

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

According to some embodiments of the present application, the permanent magnet contains dysprosium element, and the content of the dysprosium element is less than 3wt%.

According to some embodiments of the present application, the permanent magnet contains dysprosium element, and the content of the dysprosium element is less than 2.3 wt %.

According to some embodiments of the present application, the permanent magnet contains dysprosium element, and the content of dysprosium element is about 2.25wt%.

According to some embodiments of the present application, the permanent magnet contains praseodymium and neodymium elements, and the sum of the contents of the praseodymium and neodymium elements is 20wt% to 32wt%.

According to some embodiments of the present application, the permanent magnet contains praseodymium and neodymium elements, and the sum of the contents of the praseodymium and neodymium elements is 25wt% to 32wt%.

According to some embodiments of the present application, the permanent magnet contains praseodymium and neodymium elements, and the sum of the praseodymium and neodymium elements is 25wt%.

According to some embodiments of the present application, the permanent magnet contains cobalt element, and the content of the cobalt element is 1wt% to 2wt%.

According to some embodiments of the present application, a plurality of slots are provided on the end surface of the rotor core along the circumferential direction of the rotor core, and each of the permanent magnets is correspondingly embedded in each of the slots.

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

According to some embodiments of the present application, the V-shaped opening faces the motor stator.

According to some embodiments of the present application, in each phase of the stator winding, the stator windings distributed on different stator teeth are connected in series or in parallel.

According to a second aspect of the present invention, a permanent magnet motor is provided, comprising:

A motor rotor, comprising a rotor core and a plurality of permanent magnets disposed on the rotor core, wherein the number of poles of the motor rotor is 2P ≥ 8, the total width of each pole magnet is b _m , the permanent magnet contains cerium element, and the total width of each pole magnet b _m ≥ 16 mm; and

The motor stator comprises a stator core and a stator winding wound on the stator core. The stator core is arranged around the outer side of the rotor core. The stator core is provided with Q stator teeth along the inner circumference. The tooth width of the stator teeth is bt, and the relationship satisfies: Q×b _t /(P×b _m )≤1.26≤5×Q×b _t /(4×P×b _m ).

A compressor provided according to an embodiment of the third aspect of the present application includes the permanent magnet motor described above.

A refrigeration device provided according to an embodiment of the fourth aspect of the present application includes the compressor described above.

According to some embodiments of the present application, the refrigeration equipment is an air conditioner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a permanent magnet motor of the present application.

FIG. 2 is a partial schematic diagram of a slot and a permanent magnet in a permanent magnet motor.

FIG. 3 is a graph showing the relationship between the addition of cerium and the decrease in the residual magnetism of a magnet.

Figure 4 is a graph comparing motor efficiency.

Reference numerals:

100: motor rotor, 110: slot, 120: permanent magnet;

200: motor stator, 210: stator yoke, 220: stator teeth;

300: Air gap.

Detailed ways

The following are specific embodiments of the present application, and the technical solution of the present application is further described in combination with the embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

Referring to FIG. 1 and FIG. 2 , in some embodiments of the present application, the present application provides a permanent magnet motor, which includes a motor rotor 100 and a motor stator 200 . Among them:

The motor rotor 100 includes a rotor core and a plurality of permanent magnets 120 disposed on the rotor core. The number of poles of the motor rotor 100 is 2P ≥ 8, the total width of each pole magnet is b _m , the permanent magnet 120 contains a cerium element of x mass percent, and the relationship between b _m satisfies: b _m ≥ 2200/(150-x);

The motor stator 200 includes a stator core and a stator winding (not shown) wound on the stator core. The stator core is arranged around the outer side of the rotor core. The stator core is provided with Q stator teeth 220 along the inner circumference. The tooth width of the stator tooth 220 is b _t , and the relationship is satisfied: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ).

It can be understood that the permanent magnet motor of the present application includes a motor rotor 100 and a motor stator 200. The motor rotor 100 includes a rotor core and a plurality of permanent magnets 120 disposed on the rotor core. The number of poles of the motor rotor 100 is 2P ≥ 8, the total width of each pole magnet is b _m , the permanent magnet 120 contains a cerium element of x% by mass, and the relationship between b _m satisfies: b _m ≥ 2200/(150-x); the motor stator 200 includes a stator core and a stator winding wound on the stator core. The stator core is disposed around the outer side of the rotor core. The stator core is provided with Q stator teeth 220 along the inner circumference. The stator teeth 220 The tooth width is b _t , and the relationship satisfies: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ). In the permanent magnet motor of the present application, the permanent magnet 120 contains a cerium element with a mass percentage of x%, thereby reducing the use of praseodymium, neodymium and heavy rare earth elements, and effectively controlling the cost. Since the addition of cerium elements will cause the remanence of the magnet _Br to decrease, in order to ensure that the efficiency of the permanent magnet motor can meet the demand under the condition of equivalent cost, the present application is based on the mass percentage of cerium elements in the permanent magnet. The total width b _m of each pole magnet, the number Q of stator teeth 220 and the number P of poles are newly designed. When the total width b _m of each pole magnet, the cerium content x, the number Q of stator teeth 220 and the number P of poles meet the relationship defined in the present application, the magnetic properties of the magnet meet the motor efficiency requirements, the efficiency of the motor can be optimized, and the motor cost is the lowest.

It can also be understood that the excitation of the permanent magnet motor is provided by the permanent magnet 120 in the motor rotor 100, and the remanence _Br and width of the permanent magnet 120 determine the magnetic flux that the motor rotor 100 can provide. The number of motor pole pairs is P, and there are n magnets in each slot. The total width of the n magnets is the total width _bm of each pole magnet, and the magnetic flux that the permanent magnet 120 can provide is 2P× _bm × _Br . Due to the use of rare earth magnets containing cerium elements, the _Br value decreases accordingly, and the excitation of the permanent magnet 120 is reduced as a whole. When the relationship between _bm satisfies _bm≥2200 /(150-x), the magnetic properties of the permanent magnet 120 can meet the motor efficiency requirements. In addition, the magnetic flux generated by the permanent magnet 120 passes through the air gap 300, stator teeth 220, and stator yoke 210 between the motor stator 200 and the motor rotor 100, and then to the stator teeth 220, the air gap 300, and the permanent magnet 120 to form a completely closed magnetic line of force. The width b _t of the stator teeth 220 cannot be too large, otherwise the tooth magnetic density will be too small, which is not conducive to the performance; b _t cannot be too small, otherwise the tooth magnetic density will be too high, resulting in a significant increase in the motor iron loss, which will reduce the motor efficiency. The present application has found and verified through simulation analysis that when the parameters satisfy the relationship: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ), the motor efficiency can reach the optimal level under the condition of equivalent cost.

Continuing to refer to FIG. 1 and FIG. 2 , in some other embodiments of the present application, the present application provides a permanent magnet motor, which includes a motor rotor 100 and a motor stator 200 . Among them:

The motor rotor 100 includes a rotor core and a plurality of permanent magnets 120 disposed on the rotor core. The number of poles of the motor rotor 100 is 2P ≥ 8, the total width of each pole magnet is bm, the permanent magnet 120 contains cerium element, and the total width of each pole magnet bm is ≥ 16 mm.

The motor stator 200 includes a stator core and a stator winding (not shown) wound on the stator core. The stator core is arranged around the outer side of the rotor core. The stator core is provided with Q stator teeth 220 along the inner circumference. The tooth width of the stator tooth 220 is bt, and the relationship satisfies: Q×b _t /(P×b _m )≤1.26≤5×Q×b/(4×P×b _m ).

It can also be understood that the excitation of the permanent magnet motor is provided by the permanent magnet 120 in the motor rotor 100, and the remanence _Br and width of the permanent magnet 120 determine the magnetic flux that the motor rotor 100 can provide. The number of motor pole pairs is P, and there are n magnets in each slot. The total width of the n magnets is the total width bm of each pole magnet. Then the magnetic flux that the permanent magnet 120 can provide is 2P×bm × _Br . Due to the use of rare earth magnets containing cerium, the _Br value decreases accordingly, and the excitation of the permanent magnet 120 is reduced as a whole. When bm≥16mm, the magnetic properties of the permanent magnet 120 can meet the motor efficiency requirements. In addition, the magnetic flux generated by the permanent magnet 120 passes through the air gap 300, the stator teeth 220, and the stator yoke 210 between the motor stator 200 and the motor rotor 100, and then to the stator teeth 220, the air gap 300, and the permanent magnet 120 to form a whole closed magnetic line of force. Among them, the width _bt of the stator teeth 220 cannot be too large, otherwise the tooth magnetic density will be too small, which is not conducive to the performance; _bt cannot be too small, otherwise the tooth magnetic density will be too high, resulting in a significant increase in the motor iron loss, which will reduce the motor efficiency. Through simulation analysis, the present application has found and verified that when the parameters satisfy the relationship: Q×b _t /(P×b _m )≤1.26≤5×Q×b _t /(4×P×b _m ), the motor efficiency can reach an optimal level under the condition of equivalent cost.

In order to reduce the dependence on praseodymium, neodymium and heavy rare earth elements, the present application adopts a permanent magnet containing cerium, corresponding to a mass percentage of x% of cerium in the total weight of the permanent magnet. The addition of cerium will cause the remanence of the magnet to decrease, and the remanence decrease is shown in reference to Figure 3. From Figure 3, it can be seen that the decrease in the remanence _Br of the permanent magnet corresponding to different mass percentages of cerium in different permanent magnets. Due to the decrease in the remanence of the magnet, under the existing motor design, the motor flux is reduced, and the motor efficiency decreases significantly under the condition of equivalent cost. In order to apply rare earth magnets containing cerium, the present application has made a new design of the motor structure size according to the mass percentage of x% of cerium in the permanent magnet.

In some embodiments of the present application, the total width b _m of each pole magnet satisfies: 15 mm ≤ _{b m} ≤ 21 mm.

b _m is the total width of each pole magnet. When each pole magnet is composed of two permanent magnets, b _m is the sum of the widths of the two permanent magnets. Since the size of b _m directly determines the size of the excitation magnetic field of the motor, if the motor magnetic field is designed to be too large, the magnetic circuit is easily saturated and the motor efficiency tends to the maximum value; at the same time, when the motor magnetic field is too small, the motor torque coefficient is small. Under the same load, the motor operating current increases, the motor copper loss increases significantly, and the motor efficiency decreases significantly. When 15mm≤b _m ≤21mm, the motor has the best cost performance. When b _m ≥21mm, the motor efficiency does not increase significantly with the increase of the magnet width; when b _m ≤15mm, the motor efficiency decreases significantly.

In some embodiments of the present application, the mass percentage x% of the cerium element in the permanent magnet satisfies: 3%≤x%≤10%.

Since the more cerium content in the magnet, the smaller the magnet remanence _Br value, when the mass percentage of cerium exceeds 10%, the _Br value decreases significantly, the excitation magnetic field of the permanent magnet motor is too small, and the motor efficiency is poor. When the permanent magnet motor is used in a compressor, it cannot meet the energy efficiency requirements of the compressor. Therefore, in this application, the mass percentage content of cerium in the permanent magnet is 3% to 10% as an appropriate range.

Table 1 lists the corresponding change values of (150-x)×b _m when the mass percentage content of cerium x% changes from 0 to 13% when b _m is 16 mm.

Table 1 Variation of (150-x)×b _m

Table 2 lists the excitation flux in the motor, motor efficiency and motor cost when b _m changes from 13mm to 24mm.

Table 2 b _m vs. excitation flux and motor efficiency and cost

In some embodiments of the present application, the permanent magnet contains dysprosium element, and the content of dysprosium element is less than 3wt%.

In some embodiments of the present application, the permanent magnet contains dysprosium element, and the content of dysprosium element is less than 2.3wt%.

In some embodiments of the present application, the permanent magnet contains dysprosium element, and the content of dysprosium element is about 2.25wt%.

Dysprosium is a silvery-white metal that is soft and can be cut with a knife. In addition to the chemical activity common to rare earth elements and the fact that it can be used as mixed rare earth metals and compounds, dysprosium also has excellent optical, electrical, magnetic and nuclear properties. Dysprosium is used as an additive to NdFeB permanent magnets. Adding about 2wt% to 3wt% of dysprosium to the magnet can increase its coercive force. With the increasing demand for NdFeB magnets, dysprosium has become a necessary additive element, and the demand is also increasing rapidly.

In some embodiments of the present application, the permanent magnet contains praseodymium and neodymium elements, and the sum of the contents of praseodymium and neodymium elements is 20 wt % to 32 wt %.

In some embodiments of the present application, the permanent magnet contains praseodymium and neodymium elements, and the sum of the contents of praseodymium and neodymium elements is 25wt% to 32wt%.

In some embodiments of the present application, the permanent magnet contains praseodymium and neodymium elements, and the sum of the contents of praseodymium and neodymium elements is 25 wt %.

In some embodiments of the present application, the permanent magnet contains cobalt element, and the content of cobalt element is 1wt% to 2wt%.

The presence of cobalt in permanent magnets can increase coercive force and magnetic energy product.

Referring to FIG. 1 , in some embodiments of the present application, a plurality of slots 110 are provided on the end surface of the rotor core along the circumferential direction of the rotor core, and each permanent magnet 120 is correspondingly embedded in each slot 110 .

In some embodiments of the present application, the slot 110 is V-shaped.

In some embodiments of the present application, the V-shaped opening faces the motor stator 200 .

Since the intrinsic coercive force of the rare earth magnet containing cerium is lower than that of the existing conventional rare earth magnet, directly using the rare earth magnet containing cerium will reduce the demagnetization ability of the motor. The slot 110 is V-shaped, which can enhance the anti-demagnetization ability of the motor and make the demagnetization ability of the motor not lower than that of the existing conventional rare earth magnet.

It should be noted that the stator winding is divided into concentrated winding and distributed winding. Concentrated winding refers to the winding in which the coil is wound on one stator tooth. Distributed winding refers to the winding in which the coil is wound on multiple stator teeth. Specifically, the span of the concentrated winding is 1, such as slot one to slot two; while the span of the distributed winding is not 1, such as the span is 3, and the winding is from slot one to slot four. The "slot" here refers to the area formed between the stator tooth and the stator tooth. In addition, the end height of the concentrated winding is small and the cost is low; the end height of the distributed winding is relatively larger and the cost is higher, but the motor operation noise is smaller.

In some embodiments of the present application, in each phase of the stator winding, the stator windings distributed on different stator teeth are connected in series or in parallel.

It can be understood that at the same power level, the series winding used on a relatively thicker wire diameter motor can achieve a higher back electromotive force and improve the efficiency of medium and low frequency motors.

It can also be understood that at the same power level, the use of parallel windings on motors with relatively thinner wire diameters can appropriately reduce the back electromotive force, which is beneficial to improving the efficiency of high-frequency motors.

In order to facilitate understanding of the technical solution of the present application, the motor cost and motor efficiency of the permanent magnet motor of the present application and the conventional permanent magnet motor are compared, and the results are shown in Table 3 and Figure 4. In the permanent magnet of the permanent magnet motor, the content of praseodymium and neodymium is 25wt%, the content of cerium is 5wt%, the content of dysprosium is 2.25wt%, the content of cobalt is 1.5wt%, and the remaining elements are iron.

In Table 3, the permanent magnets used in the motor of the present application and conventional motor 1 and conventional motor 2 are the same, and the difference lies in the different b _t and b _m values in the structural design.

It should be noted that the permanent magnets in the motor of the present application and the conventional motors 1 and 2 can all be purchased directly from the market.

Table 3 Comparison of cost and efficiency between the permanent magnet motor of this application and conventional permanent magnet motor

In Table 3, Q×b _t /(P×b _m ) of the motor of the present application is 1.16, and the value of 1.36-x is 1.26, which satisfies the requirement of Q×b _t /(P×b _m )≤1.36-x/100 defined in the present application. The motor cost is comparable to that of conventional motors 1 and 2, but the motor efficiency is significantly improved.

The Q×b _t /(P×b _m ) of the conventional motor 1 is 1.34, and the value of 1.36-x is 1.26, which does not satisfy the Q×b _t /(P×b _m )≤1.36-x/100 defined in the present application.

The Q×b _t /(P×b _m ) of the conventional motor 2 is 1.30, and the value of 1.36-x is 1.26, which also does not satisfy the Q×b _t /(P×b _m )≤1.36-x/100 defined in the present application.

It should be noted that motor efficiency refers to the ratio of the motor's output power to its input power. For permanent magnet motors, a 0.5% increase in motor efficiency can be considered a significant efficiency improvement.

It should also be noted that the “motor cost” in Table 3 refers to the overall cost of the motor.

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

The number of stator teeth Q is greater than or equal to 12, and the number of phases of the stator winding is 3. In this design, the number of phases of the stator winding is specifically designed to be 3, which is suitable for the motors required by most compressor products. By making the number of stator teeth Q greater than or equal to 12, the number of turns of the stator winding connected in series on each stator tooth can be effectively reduced, thereby effectively reducing the intensity of the demagnetization reverse magnetic field generated by the stator winding being energized, so that the demagnetization reverse magnetic field is not sufficient to demagnetize the permanent magnet, thereby improving the overall anti-demagnetization ability of the motor.

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

The width of the stator teeth b _t cannot be too large. If it is too large, the stator slot area is small. Under the same number of motor turns, the copper wire gauge is small, and the copper loss of the motor increases significantly. At the same time, the tooth magnetic density will be too small, which is not conducive to the performance. b _t cannot be too small. If it is too small, the same rotor magnetic flux flows through the stator teeth, and the stator tooth magnetic density will be high, and the motor iron loss will increase significantly. At the same time, the tooth magnetic density is too high, resulting in a significant increase in the motor iron loss, which will reduce the motor efficiency. Therefore, in order to balance the motor iron loss and copper loss, 5mm≤b _t ≤9mm is the appropriate range.

In some other embodiments of the present application, the present application provides a compressor, the compressor comprising the present application A permanent magnet motor. The permanent magnet motor includes a motor rotor and a motor stator. The motor rotor includes a rotor core and a plurality of permanent magnets arranged on the rotor core. The number of poles of the motor rotor is 2P ≥ 8, the total width of each pole magnet is b _m , the permanent magnet contains a mass percentage of x% cerium element, and the relationship between b _m satisfies: b _m ≥ 2200/(150-x); the motor stator includes a stator core and a stator winding wound on the stator core. The stator core is arranged around the outer side of the rotor core. The stator core is provided with Q stator teeth along the inner circumference. The tooth width of the stator teeth is b _t , and the relationship satisfies: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ). In the permanent magnet motor of the present application, the permanent magnet contains a mass percentage of x% cerium element, thereby reducing the use of praseodymium, neodymium and heavy rare earth elements, and effectively controlling the cost. Since the addition of cerium will cause the remanence _Br of the magnet to decrease, in order to ensure that the efficiency of the permanent magnet motor can meet the demand under the condition of comparable cost, the total width of the magnet _{bm, the cerium content x, the number of stator teeth Q and the number of poles P are matched according to the cerium content x in the permanent magnet. When the total width of the magnet bm ,} the cerium content x, the number of stator teeth Q and the number of poles P meet the relationship defined in this application, the magnetic properties of the magnet meet the efficiency requirements of the motor, the efficiency of the motor can be optimized, and the cost of the motor is the lowest.

It can be understood that the excitation of the permanent magnet motor is provided by the permanent magnet in the motor rotor. The remanence _Br and width of the permanent magnet determine the magnetic flux that the motor rotor can provide. The number of motor pole pairs is P, and there are n magnets in each slot. The total width of the n magnets is the total width _bm of each pole magnet. Then the magnetic flux that the permanent magnet can provide is 2P× _bm × _Br . Due to the use of rare earth magnets containing cerium elements, the _Br value decreases accordingly, and the excitation of the permanent magnet is reduced as a whole. When the relationship between _bm satisfies _bm ≥2200/(150-x), the magnetic properties of the magnet can meet the motor efficiency requirements. In addition, the magnetic flux generated by the permanent magnet passes through the air gap between the motor stator and the motor rotor, the stator teeth, the stator yoke, and then to the stator teeth, air gap, and permanent magnets to form a closed magnetic line of force. Among them, the width _bt of the stator teeth cannot be too large, otherwise the tooth magnetic density will be too small, which is not conducive to the performance; _bt cannot be too small, otherwise the tooth magnetic density will be too high, resulting in a significant increase in the motor iron loss, which will reduce the motor efficiency. Through simulation analysis, the present application has found and verified that when the parameters satisfy the relationship: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ), the motor efficiency can reach the optimal level under the condition of equivalent cost. Furthermore, under the condition of equivalent cost, the compressor efficiency can reach the optimal level.

In some other embodiments of the present application, a refrigeration device is provided, and the refrigeration device includes a compressor.

It is easy to understand that the refrigeration equipment of the present application, because it uses the compressor of the present application, has all the effects and advantages of the above-mentioned permanent magnet motor and compressor. Specifically:

The compressor in the refrigeration equipment of the present application contains the permanent magnet motor of the present application, and the permanent magnet motor includes a motor rotor and a motor stator. The motor rotor includes a rotor core and a plurality of permanent magnets arranged on the rotor core, the number of poles of the motor rotor is 2P ≥ 8, the total width of each pole magnet is b _m , the permanent magnet contains a mass percentage of x% of cerium, and the relationship between b _m satisfies: b _m ≥ 2200/(150-x); the motor stator includes a stator core and a stator wound on the stator core. Winding, the stator core is arranged around the outer side of the rotor core, the stator core is provided with Q stator teeth along the inner circumference, the tooth width of the stator teeth is b _t , and the relationship is satisfied: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ). In the permanent magnet motor of the present application, the permanent magnet contains x% of cerium by mass, thereby reducing the use of praseodymium, neodymium and heavy rare earth elements, and effectively controlling the cost. Since the addition of cerium will cause the remanence B _r of the magnet to decrease, in order to ensure that the efficiency of the permanent magnet motor can meet the demand under the condition of comparable cost, the present application proposes a permanent magnet motor, according to the mass percentage x% of cerium element in the permanent magnet, the total width b _m of each pole magnet, the number of stator teeth Q and the number of poles P are matched. When the total width b _m of each pole magnet, the number of stator teeth Q and the number of poles P meet the relationship defined in the present application, the magnetic properties of the magnet meet the efficiency requirements of the motor, the efficiency of the motor can be optimized, and the cost of the motor is minimized.

In the refrigeration equipment of the present application, the excitation of the permanent magnet motor is provided by the permanent magnet in the motor rotor, and the remanence _Br and width of the permanent magnet determine the magnetic flux that the motor rotor can provide. The number of motor pole pairs is P, and there are n magnets in each slot. The total width of the n magnets is the total width _bm of each pole magnet, and the magnetic flux that the permanent magnet can provide is 2P× _bm × _Br . Due to the use of rare earth magnets containing cerium elements, the _Br value decreases accordingly, and the excitation of the permanent magnet is reduced as a whole. When the relationship between _bm satisfies _bm ≥2200/(150-x), the magnetic properties of the magnet can meet the motor efficiency requirements. In addition, the magnetic flux generated by the permanent magnet passes through the air gap, stator teeth, and stator yoke between the motor stator and the motor rotor, and then to the stator teeth, air gap, and permanent magnet to form a completely closed magnetic line of force. Among them, the width b _t of the stator teeth cannot be too large, otherwise the tooth magnetic density will be too small, which is not conducive to the performance; b _t cannot be too small, otherwise the tooth magnetic density will be too high, resulting in a significant increase in the motor iron loss, which will reduce the motor efficiency. This application has found and verified through simulation analysis that when each parameter satisfies the relationship: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ), under the condition of equivalent cost, the motor efficiency can reach the optimal level. Furthermore, under the condition of equivalent cost, the efficiency of the compressor can reach the optimal level, and finally, the efficiency of the refrigeration equipment is also improved.

In some embodiments of the present application, the refrigeration device is an air conditioner.

By arranging the compressor in the air conditioner, the overall performance of the air conditioner is improved.

In some embodiments of the present application, the air conditioner is a household air conditioner.

It should also be noted that the cerium-containing permanent magnets involved in the technical solution of this application are all products already available on the market. This application is based on the content of cerium in the cerium-containing permanent magnets, and through the structural design of the total width _bm of each pole magnet, the number of stator teeth Q, the tooth width of the stator teeth _bt and the number of poles P, to ultimately improve the performance of permanent magnet motors, compressors and refrigeration equipment.

In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", The orientations or positional relationships indicated by “axial”, “radial”, “circumferential”, etc. 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. Therefore, they should not be understood as limitations on the present application.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims (13)

A permanent magnet motor, comprising: A motor rotor, comprising a rotor core and a plurality of permanent magnets disposed on the rotor core, wherein the number of poles of the motor rotor is 2P ≥ 8, the total width of each pole magnet is b _m , the permanent magnet contains a cerium element of x mass percent, and the relationship between b _m satisfies: b _m ≥ 2200/(150-x); and The motor stator comprises a stator core and a stator winding wound on the stator core, wherein the stator core is arranged around the outer side of the rotor core, and the stator core is provided with Q stator teeth along the inner circumference, and the tooth width of the stator teeth is b _t , and the relationship satisfies: Q×b _t /(P×b _m )≤1.36-x/100≤5×Q×b _t /(4×P×b _m ). The permanent magnet motor according to claim 1, wherein the total width b _m of the magnet per pole satisfies: 15 mm ≤ b _m ≤ 21 mm. The permanent magnet motor according to claim 1 or 2, wherein the mass percentage x% of the cerium element in the permanent magnet satisfies: 3%≤x%≤10%. The permanent magnet motor according to any one of claims 1 to 3, wherein the permanent magnet contains dysprosium element, and the content of the dysprosium element is less than 3wt%. The permanent magnet motor according to any one of claims 1 to 4, wherein the permanent magnet contains praseodymium and neodymium elements, and the sum of the contents of the praseodymium and neodymium elements is 20wt% to 32wt%. The permanent magnet motor according to any one of claims 1 to 5, wherein the number Q of stator teeth satisfies: Q ≥ 12. The permanent magnet motor according to any one of claims 1 to 6, wherein the tooth width b _t of the stator teeth satisfies: 5 mm ≤ b _t ≤ 9 mm. The permanent magnet motor according to any one of claims 1 to 7, wherein a plurality of slots are provided on the end surface of the rotor core along the circumferential direction of the rotor core, and each of the permanent magnets is correspondingly embedded in each of the slots. The permanent magnet motor according to claim 8, wherein the slot (110) is V-shaped. The permanent magnet motor according to any one of claims 1 to 9, wherein the coils on the stator teeth (220) in each phase of the stator winding are connected in series or in parallel. A permanent magnet motor, comprising: A motor rotor (100), comprising a rotor core and a plurality of permanent magnets (120) arranged on the rotor core, the number of poles of the motor rotor (100) being 2P ≥ 8, the total width of each pole magnet being b _m , the permanent magnets (120) containing cerium elements, and the total width of each pole magnet being b _m ≥ 16 mm; and A motor stator (200) comprises a stator core and a stator winding wound on the stator core, wherein the stator core is arranged around the outer side of the rotor core, and the stator core is provided with Q stator teeth (220) along the inner circumference direction. The tooth width of (220) is b _t , and the relationship satisfies: Q×b _t /(P×b _m )≤1.26≤5×Q×b _t /(4×P×b _m ). A compressor, comprising the permanent magnet motor according to any one of claims 1 to 11. A refrigeration device, comprising the compressor according to claim 12.