Permanent magnet motors, compressors and refrigeration equipment

Abstract

The present invention provides a permanent magnet motor, a compressor and a refrigeration device. The permanent magnet motor according to the present invention comprises a motor rotor and a motor stator. The permanent magnet in the motor rotor contains cerium. The present invention determines the total width b of each pole magnet according to the mass percentage x% of the cerium element. m , the number of stator teeth Q and the number of poles P are designed. When the above parameters meet b m ≥2200 / (150‑x) and Q×b t / (P×b m )≤1.36‑x / 100≤5×Q×b t / (4×P×b m ), the magnetic properties of the magnets meet the motor efficiency requirements, the motor efficiency can be optimized, and the motor cost is minimized. The present invention also provides a compressor and a refrigeration device containing the above-mentioned permanent magnet motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressors, and in particular relates to a permanent magnet motor, a compressor and a refrigeration device. Background Art

[0002] Currently, in the field of household air conditioner compressors, fixed-speed models are gradually withdrawing from the market, and variable-frequency motors have become the mainstream technology. To adapt to the application environment of household air conditioners, the permanent magnets of variable-frequency motors are mostly neodymium iron boron permanent magnets containing heavy rare earth elements and high coercivity. Neodymium iron boron permanent magnets are based on the intermetallic compound Nd2Fe 14 B-based permanent magnet materials are primarily composed of neodymium, iron, and boron. To achieve different performance characteristics, other rare earth metals, such as dysprosium and praseodymium, can partially replace the neodymium in permanent magnets. With the annual increase in the number of variable-frequency motors, the consumption of heavy rare earth elements (particularly dysprosium and terbium) is also increasing. To reduce the use of heavy rare earth elements, new technologies are needed.

[0003] Compared with praseodymium and neodymium, cerium has obvious cost advantages. However, compared with the same praseodymium and neodymium, the remanence of the corresponding rare earth magnet is r 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

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the present invention provides a permanent magnet motor that improves motor efficiency while maintaining comparable cost by designing the motor structure based on the cerium content in the permanent magnet.

[0005] The present invention also provides a compressor comprising the permanent magnet motor.

[0006] The present invention also provides a refrigeration device comprising a compressor.

[0007] A first aspect of the present invention provides a permanent magnet motor, comprising:

[0008] The motor rotor comprises 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, and the total width of the magnets per pole is b. m , the permanent magnet contains x% of cerium by mass, b m The relationship satisfies: b m ≥2200 / (150-x);

[0009] The motor stator comprises a stator core and a stator winding wound on the stator core. The stator core is arranged outside 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 , the relationship satisfies: Q×b t / (P×b m )≤1.36-x / 100≤5×Q×b t / (4×P×b m ).

[0010] One of the technical solutions of the present invention regarding the permanent magnet motor has at least the following beneficial effects:

[0011] The permanent magnet motor of the present invention comprises a motor rotor and a motor stator. The motor rotor comprises 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, and the total width of each pole magnet is b. m , the permanent magnet contains x% of cerium by mass, b m The relationship 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, and the tooth width of the stator teeth is b t , 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 invention, the permanent magnet contains x% of cerium by mass, thereby reducing the use of praseodymium, neodymium and heavy rare earth elements, effectively controlling the cost. Since the addition of cerium will cause the magnet to have residual magnetism B r In order to ensure that the efficiency of the permanent magnet motor can meet the demand under the condition of comparable cost, the present invention proposes a permanent magnet motor, according to the mass percentage of cerium element in the permanent magnet x%, the total width b of each pole magnet is m , the number of stator teeth Q and the number of poles P are designed to match each other. m When the number of stator teeth Q and the number of poles P meet the relationship defined in the present invention, the magnetic properties of the magnet meet the efficiency requirements of the motor, the efficiency of the motor can be optimized, and the motor cost is minimized.

[0012] The excitation of the permanent magnet motor is provided by the permanent magnet in the motor rotor. The remanence B rThe width and width 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 b of each pole magnet. m , then the magnetic flux that the permanent magnet can provide is 2P×b m ×B r Due to the use of rare earth magnets containing cerium, B r The value decreases accordingly, and the permanent magnet excitation decreases as a whole. m The relationship satisfies b m When ≥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 magnet to form a complete closed magnetic line of force. Among them, the width b of the stator teeth is t It 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 and reducing the motor efficiency. The present invention has found and verified through simulation analysis that when the parameters meet 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 comparable cost.

[0013] According to some embodiments of the present invention, the total width b of each pole magnet is m Satisfy: 15mm≤b m ≤21mm.

[0014] b m is the total width of each pole magnet. When each pole magnet consists of two permanent magnets, b m It is the sum of the widths of the two permanent magnets. m The size of the excitation magnetic field of the motor directly determines the size of the excitation magnetic field. If the motor magnetic field is 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 When ≤21mm, the motor has the best performance / price ratio. m When the width of the magnet is greater than 21 mm, the motor efficiency does not increase significantly with the increase of the magnet width. m When the diameter is ≤15mm, the motor efficiency decreases significantly.

[0015] According to some embodiments of the present invention, the mass percentage x% of the cerium element in the permanent magnet satisfies: 3%≤x%≤10%.

[0016] As the cerium content in the magnet increases, the remanence of the magnet B r The smaller the value, the more likely it is that when the mass percentage of cerium exceeds 10%, B r The value drops significantly, the excitation magnetic field of the permanent magnet motor is too small, the motor efficiency is poor, and when the permanent magnet motor is used in a compressor, it cannot meet the energy efficiency requirements of the compressor. Therefore, in the present invention, the mass percentage content of the cerium element in the permanent magnet is 3% to 10% as an appropriate range.

[0017] According to some embodiments of the present invention, the number Q of stator teeth satisfies: Q≥12.

[0018] The number of stator teeth, Q, is greater than or equal to 12, and the stator winding has three phases. In this design, the stator winding has three phases, which is suitable for motors required by most compressor products. By setting the number of stator teeth, Q, to greater than or equal to 12, the number of stator winding turns connected in series on each stator tooth can be effectively reduced, thereby effectively reducing the intensity of the demagnetization reverse magnetic field generated by energizing the stator winding. This demagnetization reverse magnetic field is insufficient to demagnetize the permanent magnets, thereby improving the motor's overall anti-demagnetization capability.

[0019] Stator windings are divided into concentrated windings and distributed windings. Concentrated windings are windings in which the coil is wound around a single stator tooth; distributed windings are windings in which the coil is wound around multiple stator teeth. Specifically, the span of concentrated windings is 1, for example, from slot 1 to slot 2; while the span of distributed windings is not 1, for example, a span of 3, with the winding running from slot 1 to slot 4. The "slot" here refers to the area formed between the stator tooth and the stator tooth. In addition, the end height of concentrated windings is small and the cost is low; the end height of distributed windings is relatively large and the cost is higher, but the motor runs quieter.

[0020] According to some embodiments of the present invention, the tooth width b of the stator teeth t Satisfy: 5mm≤b t ≤9mm.

[0021] Width b of stator teeth t It cannot be too large. If it is too large, the stator slot area will be small. Under the same number of motor turns, the copper wire gauge will be smaller, and the copper loss of the motor will increase significantly. At the same time, the tooth magnetic flux density will be too small, which is not conducive to the performance. bt cannot be too small either. If it is too small, the same rotor magnetic flux will flow through the stator teeth, and the stator tooth magnetic flux density will be too high, which will significantly increase the iron loss of the motor. At the same time, the tooth magnetic flux density is too high, which will lead to a significant increase in the motor iron loss and reduce the motor efficiency. Therefore, in order to take into account the balance between the motor iron loss and copper loss, 5mm≤b t ≤9mm is the appropriate range.

[0022] According to some embodiments of the present invention, the permanent magnet contains dysprosium, and the content of the dysprosium is less than 3 wt %.

[0023] According to some embodiments of the present invention, the permanent magnet contains dysprosium, and the content of the dysprosium is less than 2.3 wt %.

[0024] According to some embodiments of the present invention, the permanent magnet contains dysprosium, and the content of the dysprosium is about 2.25 wt %.

[0025] According to some embodiments of the present invention, the permanent magnet contains praseodymium and neodymium elements, and the sum of the praseodymium and neodymium elements is 20 wt % to 32 wt %.

[0026] According to some embodiments of the present invention, the permanent magnet contains praseodymium and neodymium elements, and the total content of the praseodymium and neodymium elements is 25 wt % to 32 wt %.

[0027] According to some embodiments of the present invention, the permanent magnet contains praseodymium and neodymium elements, and the total content of the praseodymium and neodymium elements is 25 wt %.

[0028] According to some embodiments of the present invention, the permanent magnet contains cobalt element, and the content of the cobalt element is 1 wt% to 2 wt%.

[0029] According to some embodiments of the present invention, a plurality of slots are provided on the end surface of the rotor core along the circumference of the rotor core, and each of the permanent magnets is correspondingly embedded in each of the slots.

[0030] According to some embodiments of the present invention, the slot is V-shaped.

[0031] According to some embodiments of the present invention, the V-shaped opening faces the motor stator.

[0032] Since the intrinsic coercive force of rare earth magnets containing cerium is lower than that of existing conventional rare earth magnets, directly using rare earth magnets containing cerium will reduce the demagnetization ability of the motor. However, the V-shaped slot can enhance the motor's anti-demagnetization ability, making the motor's demagnetization ability no less than that of existing conventional rare earth magnets.

[0033] According to some embodiments of the present invention, in each phase of the stator winding, the stator windings distributed on different stator teeth are connected in series or in parallel.

[0034] At the same power level, series windings used on motors with relatively thicker wire diameters can achieve higher back electromotive force and improve the efficiency of medium and low frequency motors.

[0035] At the same power level, using 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.

[0036] A second aspect of the present invention provides a compressor, comprising the permanent magnet motor.

[0037] One of the technical solutions of the present invention regarding the compressor has at least the following beneficial effects:

[0038] The compressor of the present invention contains the permanent magnet motor, which 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, and the total width of the magnets of each pole is b. m , the permanent magnet contains x% of cerium by mass, b m The relationship 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, and the tooth width of the stator teeth is b t , 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 invention, 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 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 present invention proposes a permanent magnet motor, according to the mass percentage of x% of cerium in the permanent magnet, the total width b of each pole magnet is m , the number of stator teeth Q and the number of poles P are designed to match each other. m When the number of stator teeth Q and the number of poles P meet the relationship defined in the present invention, the magnetic properties of the magnet meet the efficiency requirements of the motor, the efficiency of the motor can be optimized, and the motor cost is minimized.

[0039] The excitation of the permanent magnet motor of the present invention is provided by the permanent magnet in the motor rotor, and the remanence B of the permanent magnet r The width and width 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 b of each pole magnet. m , then the magnetic flux that the permanent magnet can provide is 2P×b m ×B rDue to the use of rare earth magnets containing cerium, B r The value decreases accordingly, and the permanent magnet excitation decreases as a whole. m The relationship satisfies b m When ≥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 magnet to form a complete closed magnetic line of force. Among them, the width b of the stator teeth is t It 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 and reducing the motor efficiency. The present invention has found and verified through simulation analysis that when the parameters meet 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 compressor efficiency can reach the optimal level.

[0040] A third aspect of the present invention provides a refrigeration device, which includes the compressor.

[0041] One of the technical solutions of the present invention regarding refrigeration equipment has at least the following beneficial effects:

[0042] The refrigeration equipment of the present invention, because it uses the compressor of the present invention, has all the effects and advantages of the above-mentioned permanent magnet motor and compressor.

[0043] According to some embodiments of the present invention, the refrigeration device is an air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural schematic diagram of the permanent magnet motor of the present invention.

[0045] Figure 2 This is a partial schematic diagram of the slots and permanent magnets in a permanent magnet motor.

[0046] Figure 3 This is a graph showing the relationship between the addition of cerium and the decrease in the remanent magnetism of a magnet.

[0047] Figure 4 This is a comparison chart of motor efficiency.

[0048] Reference numerals:

[0049] 100: motor rotor, 110: slot, 120: permanent magnet;

[0050] 200: motor stator, 210: stator yoke, 220: stator teeth;

[0051] 300: Air gap. DETAILED DESCRIPTION

[0052] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0053] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0054] refer to Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the present invention provides a permanent magnet motor, which includes a motor rotor 100 and a motor stator 200. In which:

[0055] 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, and the total width of each pole magnet is b. m , the permanent magnet 120 contains x% of cerium by mass, b m The relationship satisfies: b m ≥2200 / (150-x);

[0056] The motor stator 200 includes a stator core and a stator winding (not shown) wound on the stator core. The stator core is arranged outside the rotor core. The stator core is provided with Q stator teeth 220 along the inner circumference. The tooth width of the stator teeth 220 is b. t , the relationship satisfies: Q×b t / (P×b m )≤1.36-x / 100≤5×Q×b t / (4×P×b m ).

[0057] It can be understood that the permanent magnet motor of the present invention 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 arranged on the rotor core. The number of poles of the motor rotor 100 is 2P ≥ 8, and the total width of each pole magnet is b. m , the permanent magnet 120 contains x% of cerium by mass, b m The relationship 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 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 teeth 220 is b t , 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 invention, the permanent magnet 120 contains x% of cerium by mass, thereby reducing the use of praseodymium, neodymium and heavy rare earth elements, effectively controlling the cost. r In order to ensure that the efficiency of the permanent magnet motor can meet the demand under the condition of comparable cost, the present invention adjusts the total width b of each pole magnet according to the mass percentage x% of cerium element in the permanent magnet. m , the number of stator teeth 220 Q and the number of poles P are newly designed. When the total width b of each pole magnet m When the cerium element content x, the number Q of stator teeth 220 and the number of poles P meet the relationship defined in the present invention, the magnetic properties of the magnet meet the efficiency requirements of the motor, the efficiency of the motor can be optimized, and the motor cost is minimized.

[0058] 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 residual magnetism B of the permanent magnet 120 r The width and the magnetic flux that the motor rotor 100 can provide determine the number of motor pole pairs P. There are n magnets in each slot. The total width of the n magnets is the total width b of each pole magnet. m , then the magnetic flux that the permanent magnet 120 can provide is 2P×b m ×B r Due to the use of rare earth magnets containing cerium, the Br value decreases accordingly, and the overall excitation of the permanent magnet 120 decreases. m The relationship satisfies b m When ≥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 between the motor stator 200 and the motor rotor 100, the stator teeth 220, the stator yoke 210, 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. Among them, the width b of the stator tooth 220 is t It cannot be too large, otherwise the magnetic density of the teeth will be too small, which is not conducive to the performance; b t It 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 invention has found and verified through simulation analysis that when the parameters meet the relationship: Q×bt / (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 comparable cost.

[0059] In order to reduce the dependence on praseodymium, neodymium and heavy rare earth elements, the present invention adopts a permanent magnet containing cerium, corresponding to the mass percentage of cerium in the total weight of the permanent magnet being x%. The addition of cerium will cause the remanence of the magnet to decrease. The remanence decrease is referenced to Figure 3 As shown. Figure 3 It can be seen that different mass percentages of cerium in different permanent magnets correspond to the remanence B of the permanent magnets. r Due to the reduced remanence of the magnets, existing motor designs also reduce the motor's magnetic flux, significantly reducing motor efficiency at comparable costs. To utilize rare earth magnets containing cerium, the present invention redesigns the motor's structural dimensions based on the x% mass percentage of cerium in the permanent magnets.

[0060] In some embodiments of the present invention, the total width b of each pole magnet is m Satisfy: 15mm≤b m ≤21mm.

[0061] b m is the total width of each pole magnet. When each pole magnet consists of two permanent magnets, b m It is the sum of the widths of the two permanent magnets. m The size of the excitation magnetic field of the motor directly determines the size of the excitation magnetic field. If the motor magnetic field is 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 When ≤21mm, the motor has the best performance / price ratio. m When the width of the magnet is greater than 21 mm, the motor efficiency does not increase significantly with the increase of the magnet width. m When the diameter is ≤15mm, the motor efficiency decreases significantly.

[0062] In some embodiments of the present invention, the mass percentage x% of the cerium element in the permanent magnet satisfies: 3%≤x%≤10%.

[0063] As the cerium content in the magnet increases, the remanence of the magnet B r The smaller the value, the more likely it is that when the mass percentage of cerium exceeds 10%, B rThe value drops significantly, the excitation magnetic field of the permanent magnet motor is too small, the motor efficiency is poor, and when the permanent magnet motor is used in a compressor, it cannot meet the energy efficiency requirements of the compressor. Therefore, in the present invention, the mass percentage content of the cerium element in the permanent magnet is 3% to 10% as an appropriate range.

[0064] Table 1 lists the m When the mass percentage of cerium changes from 0 to 13% when the diameter is 16 mm, the corresponding value is (150-x)×b m The change value of .

[0065] Table 1 (150-x)×b m Change in value

[0066] <![CDATA[b m / mm]]> x / ％ <![CDATA[(150-x)×b m ]]> <![CDATA[b m / mm]]> x / ％ <![CDATA[(150-x)×b m ]]> 16.0 0 2400 16.0 7 2288 16.0 1 2384 16.0 8 2272 16.0 2 2368 16.0 9 2256 16.0 3 2352 16.0 10 2240 16.0 4 2336 16.0 11 2224 16.0 5 2320 16.0 12 2208 16.0 6 2304 16.0 13 2192

[0067] Table 2 lists the m Field flux in the motor, motor efficiency, and motor cost when varying from 13 mm to 24 mm.

[0068] Table 2b m and excitation flux, motor efficiency, and cost

[0069] <![CDATA[b m / mm]]> Excitation flux / mWb Motor efficiency / % Motor cost / yuan 13.0 235 91.3 60.0 15.0 271 92.0 64.0 18.0 325 92.3 68.0 21.0 379 92.8 72.0 24.0 433 92.9 76.0

[0070] In some embodiments of the present invention, the permanent magnet contains dysprosium, and the content of dysprosium is less than 3 wt %.

[0071] In some embodiments of the present invention, the permanent magnet contains dysprosium, and the content of dysprosium is less than 2.3 wt %.

[0072] In some embodiments of the present invention, the permanent magnet contains dysprosium element, and the content of dysprosium element is about 2.25wt%.

[0073] Dysprosium is a silvery-white metal that is soft and can be cut with a knife. Besides possessing the chemical activity common to all rare earth elements, allowing it to be used as mixed rare earth metals and compounds, dysprosium also possesses excellent optical, electrical, magnetic, and nuclear properties. Dysprosium is used as an additive in neodymium-iron-boron (NdFeB) permanent magnets. Adding approximately 2% to 3% dysprosium by weight can increase the magnet's coercivity. With the increasing demand for NdFeB magnets, dysprosium has become a necessary additive, and demand is rapidly increasing.

[0074] In some embodiments of the present invention, the permanent magnet contains praseodymium and neodymium elements, and the total content of praseodymium and neodymium elements is 20 wt % to 32 wt %.

[0075] In some embodiments of the present invention, the permanent magnet contains praseodymium and neodymium elements, and the total content of praseodymium and neodymium elements is 25 wt % to 32 wt %.

[0076] In some embodiments of the present invention, the permanent magnet contains praseodymium and neodymium elements, and the total content of praseodymium and neodymium elements is 25 wt %.

[0077] In some embodiments of the present invention, the permanent magnet contains cobalt element, and the content of cobalt element is 1 wt% to 2 wt%.

[0078] The presence of cobalt in permanent magnets can increase coercive force and magnetic energy product.

[0079] refer to Figure 1 As shown, in some embodiments of the present invention, a plurality of slots 110 are provided on the end surface of the rotor core along the circumference of the rotor core, and each permanent magnet 120 is correspondingly embedded in each slot 110 .

[0080] In some embodiments of the present invention, the slot 110 is V-shaped.

[0081] In some embodiments of the present invention, the V-shaped opening faces the motor stator 200 .

[0082] Since the intrinsic coercive force of rare earth magnets containing cerium is lower than that of existing conventional rare earth magnets, directly using rare earth magnets containing cerium will reduce the demagnetization ability of the motor. However, 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 existing conventional rare earth magnets.

[0083] It should be noted that stator windings are divided into concentrated windings and distributed windings. Concentrated windings refer to windings in which the coil is wound around one stator tooth. Distributed windings refer to windings in which the coil is wound around multiple stator teeth. Specifically, the span of concentrated windings is 1, for example, from slot 1 to slot 2; while the span of distributed windings is not 1, for example, the span is 3, with the winding going from slot 1 to slot 4. The "slot" here refers to the area formed between the stator tooth and the stator tooth. In addition, the end height of concentrated windings is small and the cost is low; the end height of distributed windings is relatively large and the cost is higher, but the motor operation noise is lower.

[0084] In some embodiments of the present invention, in each phase of the stator winding, the stator windings distributed on different stator teeth are connected in series or in parallel.

[0085] It can be understood that at the same power level, using series windings on motors with relatively thicker wire diameters can achieve higher back electromotive force and improve the efficiency of medium and low frequency motors.

[0086] It can also be understood that at the same power level, using 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.

[0087] In order to facilitate the understanding of the technical solution of the present invention, the motor cost and motor efficiency of the permanent magnet motor of the present invention are compared with those of the conventional permanent magnet motor. The results are shown in Table 3 and Figure 4 The permanent magnets in the permanent magnet motor contain 25 wt% of praseodymium and neodymium, 5 wt% of cerium, 2.25 wt% of dysprosium, 1.5 wt% of cobalt, and the remaining element is iron.

[0088] In Table 3, the permanent magnets used in the motors of the present invention, conventional motor 1 and conventional motor 2 are the same, and the difference lies in the structural design of the motor. t and b m The values ​​are different.

[0089] It should be noted that the permanent magnets in the motor of the present invention and the conventional motors 1 and 2 can all be purchased directly from the market.

[0090] Table 3 Comparison of cost and efficiency between the permanent magnet motor of the present invention and conventional permanent magnet motor

[0091]

[0092]

[0093] In Table 3, the Q×b of the motor of the present invention is t / (P×b m ) is 1.16, and the value of 1.36-x is 1.26, which satisfies the Q×b defined in the present invention. t / (P×b m )≤1.36-x / 100, the motor cost is comparable to that of conventional motors 1 and 2, but the motor efficiency is significantly improved.

[0094] Q×b of conventional motor 1 t / (P×b m ) is 1.34, and the value of 1.36-x is 1.26, which does not meet the Q×b defined in the present invention. t / (P×b m )≤1.36-x / 100.

[0095] Q×b of conventional motor 2 t / (P×b m ) is 1.30, and the value of 1.36-x is 1.26, which also does not meet the Q×b defined in the present invention. t / (P×b m )≤1.36-x / 100.

[0096] 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 is considered a significant improvement.

[0097] It should also be noted that the “motor cost” in Table 3 refers to the overall cost of the motor.

[0098] In some embodiments of the present invention, the number Q of stator teeth satisfies: Q≥12.

[0099] The number of stator teeth, Q, is greater than or equal to 12, and the stator winding has three phases. In this design, the stator winding has three phases, which is suitable for motors required by most compressor products. By setting the number of stator teeth, Q, to greater than or equal to 12, the number of stator winding turns connected in series on each stator tooth can be effectively reduced, thereby effectively reducing the intensity of the demagnetization reverse magnetic field generated by energizing the stator winding. This demagnetization reverse magnetic field is insufficient to demagnetize the permanent magnets, thereby improving the motor's overall anti-demagnetization capability.

[0100] In some embodiments of the present invention, the tooth width b of the stator teeth is t Satisfy: 5mm≤b t ≤9mm.

[0101] Width b of stator teeth t It cannot be too large. If it is too large, the stator slot area will be small. Under the same number of motor turns, the copper wire gauge will be smaller, and the copper loss of the motor will increase significantly. At the same time, the magnetic flux density of the teeth will be too small, which is not conducive to the performance. t It cannot be too small. If it is too small, the same rotor magnetic flux will flow through the stator teeth, and the stator teeth magnetic density will be too high, which will significantly increase the motor iron loss. At the same time, the tooth magnetic density is too high, which will cause the motor iron loss to increase significantly and reduce the motor efficiency. Therefore, in order to take into account the balance between the motor iron loss and copper loss, 5mm≤b t ≤9mm is the appropriate range.

[0102] In some other embodiments of the present invention, a compressor is provided, which includes a permanent magnet motor according to the present invention. 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 disposed on the rotor core. The number of poles of the motor rotor is 2P ≥ 8, and the total width of the magnets per pole is b. m , the permanent magnet contains x% cerium by mass, b m The relationship 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 outside 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 , 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 invention, the permanent magnet contains x% of cerium by mass, thereby reducing the use of praseodymium, neodymium and heavy rare earth elements, effectively controlling the cost. Since the addition of cerium will cause the magnet to have residual magnetism B r 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 b of the magnet is adjusted according to the content x of cerium in the permanent magnet. m , cerium content x, number of stator teeth Q and number of poles P are designed to match. m When the cerium content x, the number of stator teeth Q and the number of poles P meet the relationship defined in the present invention, the magnetic properties of the magnet meet the efficiency requirements of the motor, the efficiency of the motor can be optimized, and the motor cost is minimized.

[0103] It can be understood that the excitation of the permanent magnet motor is provided by the permanent magnet in the motor rotor, and the remanence B of the permanent magnet is r The width and width 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 b of each pole magnet. m , then the magnetic flux that the permanent magnet can provide is 2P×b m ×B r Due to the use of rare earth magnets containing cerium, B r The value decreases accordingly, and the permanent magnet excitation decreases as a whole. m The relationship satisfies b m When ≥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 magnet to form a complete closed magnetic line of force. Among them, the width b of the stator teeth is t It cannot be too large, otherwise the magnetic density of the teeth will be too small, which is not conducive to the performance; b t It 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 invention has found and verified through simulation analysis that when the parameters meet 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 compressor efficiency can reach the optimal level.

[0104] In some other embodiments of the present invention, a refrigeration device is provided. The refrigeration device includes a compressor.

[0105] It is easy to understand that the refrigeration equipment of the present invention, because it uses the compressor of the present invention, has all the effects and advantages of the above-mentioned permanent magnet motor and compressor. Specifically:

[0106] The compressor of the refrigeration equipment of the present invention includes the permanent magnet motor of the present invention, which 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, and the total width of the magnets of each pole is b. m , the permanent magnet contains x% cerium by mass, b m The relationship 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 outside 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 , 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 invention, 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 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 present invention proposes a permanent magnet motor, according to the mass percentage of x% of cerium in the permanent magnet, the total width b of each pole magnet is m , the number of stator teeth Q and the number of poles P are designed to match each other. m When the number of stator teeth Q and the number of poles P meet the relationship defined in the present invention, the magnetic properties of the magnet meet the efficiency requirements of the motor, the efficiency of the motor can be optimized, and the motor cost is minimized.

[0107] In the refrigeration equipment of the present invention, the excitation of the permanent magnet motor is provided by the permanent magnet in the motor rotor, and the remanence B of the permanent magnet is r The width and width 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 b of each pole magnet. m , then the magnetic flux that the permanent magnet can provide is 2P×b m ×B r Due to the use of rare earth magnets containing cerium, B r The value decreases accordingly, and the permanent magnet excitation decreases as a whole. m The relationship satisfies b mWhen ≥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 magnet to form a complete closed magnetic line of force. Among them, the width b of the stator teeth is t It 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 and reducing the motor efficiency. The present invention has found and verified through simulation analysis that when the parameters meet 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, the compressor efficiency can reach the optimal level under the condition of equivalent cost, and ultimately the efficiency of the refrigeration equipment is also improved.

[0108] In some embodiments of the present invention, the refrigeration device is an air conditioner.

[0109] By arranging the compressor in the air conditioner, the overall performance of the air conditioner is improved.

[0110] In some embodiments of the present invention, the air conditioner is a household air conditioner.

[0111] It should also be noted that the cerium-containing permanent magnets involved in the technical solution of the present invention are all products already available on the market. The present invention is based on the content of cerium in the cerium-containing permanent magnets, by adjusting the total width b of each pole magnet. m , the number of stator teeth is Q, the width of the stator teeth is b t The structural design is carried out based on the number of poles P, ultimately improving the performance of permanent magnet motors, compressors and refrigeration equipment.

[0112] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0113] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0114] In the present invention, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0115] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean 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 invention. 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 can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0116] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A permanent magnet motor, characterized in that: include: A motor rotor (100) comprises a rotor core and a plurality of permanent magnets (120) arranged on the rotor core. The number of poles of the motor rotor (100) is 2P ≥ 8, and the total width of the magnets per pole is b. m The permanent magnet (120) contains x% by mass of cerium, b m The relationship satisfies: b m ≥2200 / (150-x); The motor stator (200) comprises a stator core and a stator winding wound on the stator core, wherein the stator core is arranged outside the rotor core, and the stator core is provided with Q stator teeth (220) along the inner circumference, and the tooth width of the stator teeth (220) is b. t , the relationship satisfies: Q×b t / (P×b m )≤1.36-x / 100≤5×Q×b t / (4×P×b m ); The permanent magnet (120) contains dysprosium, and the content of the dysprosium is less than 3 wt%.

2. The permanent magnet motor according to claim 1, characterized in that The total width b of each pole magnet m Satisfy: 15mm≤b m ≤21mm.

3. The permanent magnet motor according to claim 1, characterized in that: The mass percentage x% of the cerium element in the permanent magnet (120) satisfies: 3%≤x%≤10%.

4. The permanent magnet motor according to claim 1, characterized in that: The permanent magnet (120) contains praseodymium and neodymium elements, and the sum of the praseodymium and neodymium elements is 20 wt% to 32 wt%.

5. The permanent magnet motor according to claim 1, characterized in that: The number Q of the stator teeth (220) satisfies: Q≥12.

6. The permanent magnet motor according to claim 1, characterized in that: The tooth width b of the stator tooth (220) t Satisfy: 5mm≤b t ≤9mm.

7. The permanent magnet motor according to any one of claims 1 to 6, characterized in that: A plurality of slots (110) are provided on the end surface of the rotor core along the circumference of the rotor core, and each permanent magnet (120) is correspondingly embedded in each slot (110).

8. The permanent magnet motor according to claim 7, characterized in that: The slot (110) is V-shaped.

9. The permanent magnet motor according to claim 1, characterized in that: The stator winding is formed by connecting the coils on the stator teeth (220) in each phase in series or in parallel.

10. A compressor, characterized in that: The compressor comprises the permanent magnet motor according to any one of claims 1 to 9.

11. A refrigeration device, characterized in that: The refrigeration equipment includes the compressor according to claim 10.

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