CN117955267A - Motor, compressor and refrigeration equipment - Google Patents

Abstract

The invention discloses a motor, a compressor and refrigeration equipment. The motor comprises a stator and a rotor, wherein permanent magnets in the rotor are cerium-containing permanent magnets, the stator comprises a stator core, the length of the stator core is L, and the motor meets the following conditions: and 1.5 x L.ltoreq.Ke.ltoreq.1.8-x/100) L, wherein x/100 is the mass percentage of cerium contained in the permanent magnet, ke is the counter potential of the motor at 20 ℃ and 1000rpm, ke is in units of V/krpm, and L is in units of mm. According to the invention, the Ke value is ensured by adjusting the length of the stator core according to the mass percentage of cerium in the permanent magnet, so that the cost is reduced and the motor efficiency is improved. The invention also provides a compressor and refrigeration equipment comprising the motor.

Description

Motor, compressor and refrigeration equipment

Technical Field

The invention belongs to the technical field of motors, and particularly relates to a motor, a compressor and refrigeration equipment.

Background

The variable frequency motor has become the mainstream motor of home appliance compressors such as air conditioner, refrigerator. Most of the permanent magnets of the variable frequency motor are neodymium-iron-boron permanent magnets, and along with the increase of market demand of the variable frequency motor and the rising of price of rare earth materials, the cost of the neodymium-iron-boron permanent magnets and the motor is increased.

The neodymium-iron-boron permanent magnet contains a considerable amount of rare earth elements such as praseodymium and neodymium, and the dosage of praseodymium and neodymium elements in the permanent magnet can be reduced by using the cerium-containing permanent magnet to replace the conventional neodymium-iron-boron permanent magnet, so that the cost is reduced, and the sustainable development of the industry is promoted. However, with addition of cerium element and reduction of praseodymium and neodymium element content, the coercive force of the permanent magnet is reduced, which results in reduction of demagnetization resistance and efficiency loss of the motor.

Therefore, how to reduce the cost and simultaneously consider the motor performance is a problem to be solved at present.

Disclosure of Invention

The present invention aims to solve at least one of the above technical problems in the prior art. Therefore, the invention provides the motor, which can reduce the cost and ensure the motor efficiency.

The invention also provides a compressor comprising the motor.

The invention also provides refrigeration equipment comprising the motor or the compressor.

A first aspect of the present invention provides an electric machine comprising:

a stator including a stator core having a length L;

The rotor comprises a rotor core and a plurality of permanent magnets arranged on the rotor core, wherein cerium is contained in the permanent magnets;

The motor satisfies: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) x L;

wherein x/100 is the mass percent of cerium contained in the permanent magnet, ke is the counter potential of the motor at 20 ℃ and 1000rpm, ke is V/krpm, and L is mm.

The motor of the first aspect of the invention has at least the following beneficial effects:

According to the mass percentage x/100 of cerium in the permanent magnet, the length L of the stator core is changed, and the value range of Ke value is adjusted, so that Ke value meets the following conditions: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) L, whereby the problem of reduced counter potential due to the use of cerium-containing permanent magnets can be solved by changing the length of the stator core, thereby improving motor efficiency. The cost of the cerium-containing permanent magnet is lower than that of a conventional neodymium-iron-boron permanent magnet, so that the motor efficiency is ensured, the cost of the motor is reduced, and the cost performance of the motor is improved.

Specifically, when a cerium-containing permanent magnet is used as a magnetic pole of a rotor, the remanence of the permanent magnet decreases, and the air-gap density of the motor decreases. According to the counter potential E calculation formula: e=4.44 fNK Φ, where Φ is magnetic flux, Φ=bδ=s, s+_l, bδ is air gap flux density, f is current frequency, N is winding number, K is winding coefficient, it is easy to understand that if permanent magnet remanence decreases, air gap flux density bδ decreases, resulting in decrease in counter potential E or Ke value. And the output power of the motorThe back emf of the motor during operation cannot be too low, otherwise the current will increase and the motor efficiency will decrease. According to the invention, the motor is adaptively designed according to the mass percent of cerium in the permanent magnet, the length of the stator core is increased, and then the magnetic flux area S is increased, so that the Ke value reaches the range of 1.5L- (1.8-x/100) L, the efficiency loss of the motor can be avoided, and the purpose of reducing the cost is realized through the use of the cerium-containing permanent magnet.

According to some embodiments of the invention, the mass percentage x/100 of cerium in the permanent magnet satisfies: x/100 is more than 0 and less than or equal to 0.1.

According to some embodiments of the invention, the mass percentage x/100 of cerium in the permanent magnet satisfies: x/100 is more than 0 and less than or equal to 0.06.

The higher the cerium content, the more the coercivity of the permanent magnet is reduced under the same remanence, and the motor needs to be designed to reduce the number of turns under the condition of meeting the same demagnetizing current, so that the Ke value is reduced. The mass percentage of cerium in the permanent magnet is controlled to be not more than 10%, so that better cost performance can be obtained. Further, the effect is optimal when the mass percentage of cerium is not more than 6%.

According to some embodiments of the invention, the mass percentage x/100 of cerium in the permanent magnet satisfies: x/100 is less than or equal to 0.03 and less than or equal to 0.1.

According to some embodiments of the invention, the mass percentage x/100 of cerium in the permanent magnet satisfies: x/100 is less than or equal to 0.03 and less than or equal to 0.06.

When the cerium content in the permanent magnet is more than 3%, the cost reduction effect is better.

According to some embodiments of the invention, the permanent magnet has a remanence at 20 ℃ of 1.30T or more. The remanence of the permanent magnet is related to temperature, and when the cerium-containing permanent magnet is used, the remanence Br of the permanent magnet at 20 ℃ is more than or equal to 1.30T, so that the magnetic flux and counter potential are ensured, and the anti-demagnetizing capability and efficiency of the motor are improved.

According to some embodiments of the invention, the permanent magnet has a remanence at 20 ℃ of 1.32T or more. Furthermore, the demagnetizing rate of the motor at 130 ℃/22A is less than 1.8%, and the motor efficiency is more than 92.4%.

According to some embodiments of the invention, the permanent magnet has a remanence of 1.32T at 20 ℃. Furthermore, the demagnetizing rate of the motor at 130 ℃/22A can reach 1.6% -1.8%, and the motor efficiency can reach 92.4% -93.5%.

According to some embodiments of the invention, the permanent magnet has a thickness of 1.5mm-2.5mm.

Increasing the thickness of the permanent magnet can increase the remanence, but also increase the cost. The thickness of the permanent magnet is controlled within the range, so that the cost and the demagnetization resistance can be better considered.

According to some embodiments of the invention, the permanent magnet has a thickness of 1.5mm-2.0mm. As examples, the permanent magnet may have a thickness of about 1.5mm, 1.6mm, 1.7mm, or 1.8mm.

According to some embodiments of the invention, the stator core is provided with a plurality of stator slots.

According to some embodiments of the invention, the number of stator slots is 12 or more.

With the increase of the number of stator slots, the number of winding turns is reduced, the anti-demagnetizing capability of the motor is enhanced, the coercive force of the permanent magnet can be reduced to increase remanence, and the back electromotive force drop caused by cerium doping is inhibited. Thereby, a permanent magnet having a higher cerium content can be used, further reducing costs. On the contrary, if the number of stator slots is reduced, in order to make the permanent magnet difficult to demagnetize, the thickness of the permanent magnet needs to be increased or the coercive force of the permanent magnet needs to be increased, which increases the cost.

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

According to some embodiments of the invention, the number of poles of the rotor is ≡8.

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

According to some embodiments of the invention, the number of stator slots is 12 and the number of poles of the rotor is 8, 10 or 14.

According to some embodiments of the invention, the number of stator slots is 15 and the number of poles of the rotor is 10, 14 or 16.

It will be appreciated that the number of stator slots of the permanent magnet machine and the number of poles of the rotor adapted may be combined in a variety of ways and are not limited to the type illustrated. Overall, as the number of stator slots increases, the maximum number of poles that are adapted can be suitably increased.

According to some embodiments of the invention, the stator core is provided with a plurality of stator teeth, and each stator tooth is wound with a stator winding.

The stator winding components of the permanent magnet synchronous motor are distributed and centralized. The concentrated winding has small height of the end part and low cost; the distributed windings are relatively larger in end height and more costly, but the motor is less noisy to operate.

According to some embodiments of the invention, a concentrated winding is wound on each of the stator teeth.

According to some embodiments of the invention, the number of turns of the concentrated winding on each of the stator teeth is N, the number of parallel branches per phase of the concentrated winding is a, then:

when the connection form of the concentrated winding on the stator teeth is Y-connection, N and a satisfy: n/a is less than or equal to (25-x) 26/5; when the connection form of the concentrated winding on the stator teeth is a delta connection, N and a satisfy: n/a.ltoreq.25-x.26.sqrt (3)/5.

The number of turns of windings is too high, the demagnetizing magnetic potential of the motor is increased, the demagnetizing resistance can be reduced, the thickness of the permanent magnet is required to be increased or the coercive force of the permanent magnet is required to be improved to ensure the performance of the motor, and the cost performance of the motor can be reduced. Limiting N, a, x satisfies the above relationship, better balancing motor performance and cost.

According to some embodiments of the invention, when the connection form of the concentrated windings on the stator teeth is Y-connection, the number of turns of the concentrated windings on each of the stator teeth is N: n is more than or equal to 50 and less than or equal to 90.

According to some embodiments of the invention, when the connection form of the concentrated windings on the stator teeth is Y-connection, the number of turns of the concentrated windings on each of the stator teeth is N: n is more than or equal to 50 and less than or equal to 80.

According to some embodiments of the invention, when the connection form of the concentrated windings on the stator teeth is Y-connection, the number of turns N of the concentrated windings on each of the stator teeth is 80.

According to some embodiments of the invention, when the connection form of the concentrated windings on the stator teeth is a delta connection, the number of turns N of the concentrated windings on each of the stator teeth satisfies: n is more than or equal to 80 and less than or equal to 170.

According to some embodiments of the invention, the number of parallel branches per phase of the concentrated winding, a, is: a is more than or equal to 1 and less than or equal to 4.

According to some embodiments of the invention, the number of parallel branches per phase of the concentrated winding a is 1.

According to some embodiments of the invention, the length L of the stator core satisfies: l is more than or equal to 20mm and less than or equal to 50mm.

When the length of the stator core increases, the core loss increases and the copper loss decreases. In the above-defined range, as the length of the stator core increases, the copper loss reduction value is higher than the iron loss increase value, and therefore, the overall loss of the motor decreases and the motor efficiency increases. If the length of the stator core is further increased, the copper loss reduction value may be lower than the iron loss increase value, and the motor efficiency may be adversely affected.

According to some embodiments of the invention, the length L of the stator core satisfies: l is more than or equal to 30mm and less than or equal to 40mm.

As an example, the length L of the stator core may be 30mm, 35mm.

According to some embodiments of the invention, the outer diameter D of the rotor satisfies: d is more than or equal to 40mm and less than or equal to 80mm.

The increase of the magnetic flux areas S & gtDS 2, D can improve the counter potential, and is beneficial to increasing the content of cerium element in the permanent magnet. However, when the outer diameter of the rotor is too large, if the area of the stator groove is kept unchanged, the outer diameter of the motor is increased, so that the consumption cost of silicon steel is increased; if the motor size is maintained, the stator slot area is reduced and the current density is increased, resulting in reduced motor reliability.

According to some embodiments of the invention, the outer diameter D of the rotor satisfies: d is more than or equal to 40mm and less than or equal to 65mm.

According to some embodiments of the invention, the rotor core is provided with a plurality of rotor slots, and the permanent magnets are respectively arranged in the rotor slots.

One or more permanent magnets can be arranged in one rotor slot, and all the permanent magnets in the same rotor slot form one magnetic pole.

According to some embodiments of the invention, more than two permanent magnets are arranged in each rotor groove, which is beneficial to reducing the magnetic density of stator teeth, reducing iron loss and increasing the anti-demagnetizing capability of the motor.

According to some embodiments of the invention, the rotor groove is V-shaped.

According to some embodiments of the invention, the rotor groove is V-shaped, and each two permanent magnets are symmetrically arranged at two sides of the V-shaped rotor groove.

The V-shaped rotor grooves are adopted, and two permanent magnets are symmetrically arranged in each rotor groove, so that the width of a magnetic pole can be increased, the iron loss is reduced, and the anti-demagnetizing capability is enhanced.

According to some embodiments of the invention, the V-shaped opening is directed towards the outside of the rotor.

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

According to some embodiments of the invention, the permanent magnet has a total mass percent of praseodymium and neodymium of 25% to 32%.

According to some embodiments of the invention, dysprosium and/or terbium is contained in the permanent magnet, wherein the total mass percent of dysprosium terbium is less than or equal to 3%.

Dysprosium and terbium are heavy rare earth elements, and the coercive force of the permanent magnet can be improved.

According to some embodiments of the invention, the permanent magnet further comprises cobalt, wherein the mass percentage of cobalt is less than or equal to 2%.

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

The permanent magnet contains cobalt, so that the coercive force can be improved.

According to some embodiments of the invention, the permanent magnet further contains trace amounts of other elements including manganese, copper, gallium, terbium and niobium, so as to improve the comprehensive properties of the permanent magnet, such as working temperature and stability.

According to some embodiments of the invention, the total mass percentage of the other elements is less than or equal to 2%.

According to some embodiments of the invention, the permanent magnet consists essentially of, in mass percent:

20-32% of praseodymium and neodymium, 3-10% of cerium, 0-3% of dysprosium and terbium, 1-2% of cobalt and the balance of iron.

A second aspect of the invention provides a compressor comprising the motor.

The compressor of the second aspect of the present invention has at least the following advantageous effects:

The compressor of the invention has at least all the beneficial effects brought by the technical proposal of the motor because the motor of the invention is used.

Specifically, the compressor of the present invention comprises the motor of the present invention, which comprises a stator and a rotor. The stator comprises a stator core, wherein the length of the stator core is L; the rotor comprises a rotor core and a plurality of permanent magnets arranged on the rotor core, wherein cerium is contained in the permanent magnets; the motor satisfies: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) x L; wherein x/100 is the mass percent of cerium contained in the permanent magnet, ke is the counter potential of the motor at 20 ℃ and 1000rpm, ke is V/krpm, and L is mm.

According to the mass percentage x/100 of cerium in the permanent magnet, the length L of the stator core is changed, and the value range of Ke value is adjusted, so that Ke value meets the following conditions: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) L, whereby the problem of reduced counter potential due to the use of cerium-containing permanent magnets can be solved by changing the length of the stator core, thereby improving motor efficiency. The cost of the cerium-containing permanent magnet is lower than that of a conventional neodymium-iron-boron permanent magnet, so that the motor efficiency is ensured, the cost of the motor is reduced, and the cost performance of the motor is improved. Furthermore, the efficiency of the compressor can be ensured, and meanwhile, the cost of the compressor is reduced, and the cost performance of the compressor is improved.

A third aspect of the invention provides a refrigeration appliance comprising said motor or said compressor.

The refrigeration equipment of the third aspect of the invention has at least the following advantages:

The refrigeration equipment of the invention has at least all the beneficial effects brought by the technical proposal of the motor or the compressor because the motor or the compressor of the invention is used.

Further, the refrigeration equipment of the invention comprises the compressor of the invention, and the compressor comprises the motor of the invention, and the motor comprises a stator and a rotor. The stator comprises a stator core, wherein the length of the stator core is L; the rotor comprises a rotor core and a plurality of permanent magnets arranged on the rotor core, wherein cerium is contained in the permanent magnets; the motor satisfies: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) x L; wherein x/100 is the mass percent of cerium contained in the permanent magnet, ke is the counter potential of the motor at 20 ℃ and 1000rpm, ke is V/krpm, and L is mm.

According to the mass percentage x/100 of cerium in the permanent magnet, the length L of the stator core is changed, and the value range of Ke value is adjusted, so that Ke value meets the following conditions: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) L, whereby the problem of reduced counter potential due to the use of cerium-containing permanent magnets can be solved by changing the length of the stator core, thereby improving motor efficiency. The cost of the cerium-containing permanent magnet is lower than that of a conventional neodymium-iron-boron permanent magnet, so that the motor efficiency is ensured, the cost of the motor is reduced, and the cost performance of the motor is improved. Finally, the efficiency of the refrigeration equipment can be ensured, and meanwhile, the cost is reduced, and the cost performance of the refrigeration equipment is improved.

According to some embodiments of the invention, the refrigeration appliance includes an air conditioner, a refrigerator, or an ice bin.

Drawings

Fig. 1 is a structural cross-sectional view of a motor according to an embodiment of the present invention.

Reference numerals:

110. A stator; 111. stator teeth; 112. a stator groove;

120. a rotor; 121. a rotor core; 122. a rotor groove; 123. permanent magnets.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements or elements having the same function throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

In the description of the present invention, reference is made to an orientation description, for example, an orientation or positional relationship indicated above, below, etc. based on the orientation or positional relationship shown in the drawings, for convenience of description and simplification of the description, only, and it is not indicated or implied that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present invention can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.

In the description of the present invention, a number refers to one or more, a plurality refers to two or more, and "above" includes this number.

Referring to fig. 1, for one embodiment of the present invention, there is provided an electric machine including a stator 110 and a rotor 120. Wherein the stator 110 includes a stator core having a length L; the rotor 120 includes a rotor core 121 and a plurality of permanent magnets 123 provided on the rotor core 121, and cerium is contained in the permanent magnets 123.

Wherein, the motor satisfies: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) x L; x/100 is the mass percent of cerium contained in the permanent magnet 123, ke is the counter potential of the motor at 20℃at 1000rpm, ke is in V/krpm, and L is in mm.

It can be appreciated that when the permanent magnet 123 containing cerium is used as the magnetic pole of the rotor 120, the remanence of the permanent magnet 123 decreases and the motor air gap density decreases. According to the calculation formula of the counter potential E: e=4.44 fNK Φ, where Φ is magnetic flux, Φ=bδ=s, s+_l, bδ is air gap flux density, f is current frequency, N is winding number, K is winding coefficient, it is easy to understand that if the remanence of the permanent magnet 123 decreases, the decrease in air gap flux density bδ will result in decrease in counter potential E or Ke value. And the output power of the motorThe back emf of the motor during operation cannot be too low, otherwise the current will increase and the motor efficiency will decrease.

The invention adaptively designs the motor according to the mass percent of cerium in the permanent magnet 123, and increases the magnetic flux area S by increasing the length of the stator core, so that Ke reaches the range of 1.5L- (1.8-x/100) L, thereby solving the problems of residual magnetism and air gap flux density reduction caused by using the permanent magnet 123 containing cerium, and further avoiding the efficiency loss of the motor by increasing the length of the stator core. The cost of the permanent magnet 123 containing cerium is lower than that of a conventional neodymium-iron-boron permanent magnet, so that the motor efficiency is ensured, the cost of the motor is reduced, and the cost performance of the motor is improved.

As an embodiment, the mass percentage x/100 of cerium in the permanent magnet 123 satisfies: x/100 is more than 0 and less than or equal to 0.1. As a more preferred embodiment, the mass percentage x/100 of cerium in the permanent magnet 123 satisfies: x/100 is more than 0 and less than or equal to 0.06.

The higher the cerium content, the more the coercivity of the permanent magnet 123 decreases at the same remanence, and the motor needs to be designed to decrease the number of turns under the condition of meeting the same demagnetizing current, resulting in the decrease of the Ke value. The mass percentage of cerium in the permanent magnet 123 is controlled to be not more than 10%, so that better cost performance can be obtained. Further, the effect is optimal when the mass percentage of cerium is not more than 6%.

As an embodiment, the mass percentage x/100 of cerium in the permanent magnet 123 satisfies: x/100 is less than or equal to 0.03 and less than or equal to 0.1. As a more preferred embodiment, the mass percentage x/100 of cerium in the permanent magnet 123 satisfies: x/100 is less than or equal to 0.03 and less than or equal to 0.06. The cerium content range can ensure the cost reduction range and optimize the motor efficiency, thereby better considering the cost and the motor efficiency.

Referring to Table 1, the cerium content x/100 is 0 to 0.15, and the length L of the stator core is 25mm, 30mm, or 35mm, and the corresponding Ke value interval [ Ke (min), ke (max) ].

Table 1 motor-related parameter values

As one embodiment, the permanent magnet 123 has a remanence at 20 ℃ of 1.30T or more.

Too low remanence can affect the magnetic flux of the rotor 120 at 20 c, reducing the electromotive force and, in turn, the motor efficiency.

As one embodiment, the permanent magnet 123 has a remanence at 20 ℃ of 1.32T or more. Furthermore, the demagnetizing rate of the motor at 130 ℃/22A is less than 1.8%, and the motor efficiency is more than 92.4%.

For example, when the remanence of the permanent magnet 123 at 20 ℃ is 1.32T, the demagnetizing rate of the motor at 130 ℃/22A can reach 1.6% -1.8%, and the motor efficiency reaches 92.4% -93.5%.

Referring to fig. 1, as an embodiment, a plurality of stator slots 112 are provided in the stator core.

As one embodiment, the number of stator slots 112 is 12 or more.

As the number of stator slots 112 increases, the number of winding turns decreases, the demagnetizing resistance of the motor increases, the coercive force of the permanent magnet 123 can be reduced to increase remanence, and the drop of counter potential due to cerium doping is suppressed. Thereby, the permanent magnet 123 having a higher cerium content can be used, further reducing the cost.

For example, a typical motor is designed to be three-phase, with N number of turns in series per phase, and when the number of stator slots 112 is 9, the number of slots per phase is 3, and the number of turns per tooth Nc is N/3; when the number of stator slots 112 is 12, the number of slots per phase is 4 and the number of turns per tooth Nc is N/4. I.e. the greater the number of stator slots 112, the lower Nc. As is known from the demagnetizing potential f=nc×i (I is a demagnetizing current, which is constant), the lower Nc is, the lower the demagnetizing potential is, the lower the coercive force requirement for the permanent magnet 123 is, and the thinner permanent magnet 123 or the permanent magnet 123 having a lower coercive force can be used.

On the contrary, if the number of stator slots 112 is reduced, in order to make the permanent magnet 123 not easy to demagnetize, it is necessary to increase the thickness of the permanent magnet 123 or increase the coercive force of the permanent magnet 123, which increases the cost.

As one embodiment, the number of stator slots 112 is 12 or 15.

As one embodiment, the number of poles of rotor 120 is greater than or equal to 8. For example, the number of poles of the rotor 120 may be 8-16, and more specifically, the number of poles of the rotor 120 may be 8, 10, 14, or 16.

As one embodiment, the number of stator slots 112 is 12 and the number of poles of the rotor 120 is 8, 10 or 14.

As one embodiment, the number of stator slots 112 is 15, and the number of poles of the rotor 120 is 10, 14 or 16.

It will be appreciated that the number of stator slots 112 of the permanent magnet machine and the number of poles of the rotor 120 adapted may be combined in a variety of ways and are not limited to the type illustrated. For example, when the number Q of stator slots 112 is 12, the number of poles adapted may be 8, 10, 14, or the like. Overall, as the number of stator slots 112 increases, the maximum number of poles that are adapted may be suitably increased.

As an embodiment, a plurality of stator teeth 111 are provided on the stator core, and a stator winding is wound on each stator tooth 111.

The stator winding components of the permanent magnet synchronous motor are distributed and centralized. The concentrated winding has small height of the end part and low cost; the distributed windings are relatively larger in end height and more costly, but the motor is less noisy to operate.

As an embodiment, a concentrated winding is wound around each stator tooth 111.

As a more preferred embodiment, the number of turns of the concentrated winding on each stator tooth 111 is N, and the number of branches of each phase of the concentrated winding connected in parallel is a, then the motor also satisfies: when the connection form of the concentrated winding on the stator teeth 111 is Y-connection, N and a satisfy: n/a is less than or equal to (25-x) 26/5; when the connection form of the concentrated winding on the stator teeth 111 is a delta connection, N and a satisfy: n/a.ltoreq.25-x.26.sqrt (3)/5.

If the number of winding turns is too high, the demagnetizing magnetic potential of the motor will increase and the demagnetizing resistance will decrease. In this case, it is necessary to increase the thickness of the permanent magnet 123 or to increase the coercive force of the permanent magnet 123 to secure the motor performance, but at the same time, the cost is increased. By controlling N/a in the above range, a better balance between cost and motor performance can be achieved.

As an embodiment, when the connection form of the concentrated windings to the stator teeth 111 is Y-connection, the number of turns of the concentrated windings on each stator tooth 111 is N: n is more than or equal to 50 and less than or equal to 90. As a more preferred embodiment, the number of turns N of the concentrated winding satisfies: n is more than or equal to 50 and less than or equal to 80. For example, the number of turns N of the concentrated winding may be 80.

As an embodiment, when the connection form of the concentrated winding on the stator teeth is a delta connection, the number of turns N of the concentrated winding on each stator tooth satisfies: n is more than or equal to 80 and less than or equal to 170.

As an embodiment, the number a of parallel branches per phase of the concentrated winding is: a is more than or equal to 1 and less than or equal to 4. For example, a may be 1.

As one embodiment, the length L of the stator core satisfies: l is more than or equal to 20mm and less than or equal to 50mm.

When the length of the stator core increases, the core loss increases and the copper loss decreases. In the above-defined range, as the length of the stator core increases, the copper loss reduction value is higher than the iron loss increase value, and therefore, the overall loss of the motor decreases and the motor efficiency increases. If the length of the stator core is further increased, the copper loss reduction value may be lower than the iron loss increase value, and the motor efficiency may be adversely affected.

As one embodiment, the length L of the stator core satisfies: l is more than or equal to 30mm and less than or equal to 40mm. For example, the length L of the stator core may be 30mm, 35mm.

As one embodiment, the outer diameter D of the rotor 120 satisfies: d is more than or equal to 40mm and less than or equal to 80mm.

The increase of the magnetic flux area S.gtDS 2 can increase the magnetic flux area, raise the counter potential, and further facilitate the increase of the cerium element content in the permanent magnet 123. However, when the outer diameter of the rotor 120 is too large, if the area of the stator slot 112 is kept unchanged, the outer diameter of the motor will increase, resulting in the increase of the silicon steel consumption cost; if the motor size is maintained, the stator slot 112 area may decrease and the current density may increase, affecting motor reliability.

As one embodiment, the outer diameter D of the rotor 120 satisfies: d is more than or equal to 40mm and less than or equal to 65mm.

Referring to fig. 1, as an embodiment, a plurality of rotor slots 122 are provided in a rotor core 121, and a plurality of permanent magnets 123 are provided in the plurality of rotor slots 122, respectively.

It will be appreciated that one or more permanent magnets 123 may be provided within one rotor slot 122, all permanent magnets 123 located within the same rotor slot 122 constituting one magnetic pole. When more than two permanent magnets 123 are arranged in each rotor groove 122, the magnetic density of the stator teeth 111 is reduced, the iron loss is reduced, and the anti-demagnetizing capability of the motor is improved.

As one embodiment, the rotor groove 122 has a V-shape, and each two permanent magnets 123 are symmetrically disposed at both sides of the V-shape rotor groove 122.

The V-shaped rotor grooves 122 are adopted, and two permanent magnets 123 are symmetrically arranged in each rotor groove 122, so that the magnetic pole width can be increased, the iron loss can be reduced, and the anti-demagnetizing capability can be enhanced.

Referring to fig. 1, in one embodiment, the rotor groove 122 has a V-shaped structure that opens toward the outside of the rotor 120.

As one embodiment, the permanent magnet 123 has a thickness of 1.5mm-2.5mm. Further, the permanent magnet 123 has a thickness of 1.5mm to 2.0mm.

Increasing the thickness of the permanent magnet 123 can increase the remanence, but also increases the cost of the permanent magnet 123. Controlling the thickness of the permanent magnet 123 within the above range can ensure anti-demagnetization performance, realizing better cost performance.

As one embodiment, the permanent magnet 123 contains praseodymium and neodymium, wherein the total mass percent of the praseodymium and neodymium is 20% -32%. Further, the total mass percent of praseodymium and neodymium is 20-32%.

In one embodiment, the permanent magnet 123 contains dysprosium and/or terbium, wherein the total mass percent of dysprosium terbium is less than or equal to 3%.

As one embodiment, the permanent magnet 123 contains cobalt, and the mass percentage of cobalt is 1% -2%.

The permanent magnet 123 contains elements including dysprosium, terbium, and cobalt, and can improve coercive force.

As an embodiment, the permanent magnet 123 contains a trace amount of other elements selected from manganese, copper, gallium, terbium, niobium, etc., for improving the comprehensive properties of the permanent magnet 123 such as the operating temperature and stability.

As one embodiment, the total mass percent of the other elements is less than or equal to 2 percent.

As an embodiment, the composition of the permanent magnet 123 in mass percent is as follows: 20-32% of praseodymium and neodymium, 3-10% of cerium, 0-3% of dysprosium and terbium, 1-2% of cobalt and the balance of iron.

The permanent magnet 123 described above is commercially available or is prepared using methods known to those of ordinary skill in the art and not described in detail herein.

The invention is further illustrated by the following example embodiments.

Example 1

The motor of the present embodiment, as shown in fig. 1, includes a stator 110 and a rotor 120.

The stator 110 includes a stator core having 12 stator teeth 111 and 12 stator slots 112. The length l=35 mm of the stator core, and the outer diameter of the stator 110 is 101mm. Each stator tooth 111 is wound with a centralized winding (not shown), the connection form of the centralized winding on the stator tooth 111 is triangular connection, the number of turns of the centralized winding on each stator tooth 111 is n=140, and the number of parallel branches of the centralized winding is a=1.

The rotor 120 includes a rotor core 121 and 16 permanent magnets 123, and an outer diameter d=56.4 mm of the rotor 120. The rotor core 121 is provided with 8V-shaped rotor grooves 122 which are open outward uniformly along the circumferential direction of the cross section. Every two permanent magnets 123 are symmetrically distributed on two sides of the V-shaped groove, and the permanent magnets 123 in each rotor groove 122 form a magnetic pole, and 8 poles are formed.

Permanent magnet 123 is commercially available, model: 42SHC. Permanent magnet 123 consists essentially of (in mass): praseodymium and neodymium are 25%, cerium is x% =5%, dysprosium is 2.25%, cobalt is 1-2%, and the rest is mainly iron, and trace elements such as manganese, copper, gallium, niobium, aluminum and the like.

The main parameters of the motor of example 1 are shown in table 2.

The motor satisfies: 1.5×l=1.5×35=52.5×ke=55.5×l=1.8-x/100+35=61.25.

The motor also satisfies: n/a=140 + (25-x) 26×sqrt (3)/5= (25-5) 26×sqrt (3)/5= 180.13.

Where Ke is the back-emf of the motor at 20℃and 1000 rpm. The Ke value test method is as follows:

(1) Placing the motor in an environment of 20 ℃ for more than 4 hours;

(2) The motor is fixedly installed, and the centers of the stator and the rotor are aligned;

(3) And dragging the rotor by adopting a servo motor, wherein the rotating speed is 1000rpm, and testing the line voltage of the motor to obtain the Ke value.

Table 2 part of motor parameters of example 1

Example 2

The difference compared with embodiment 1 is that the winding connection is Y-connected, and the main parameters of the motor of this embodiment are shown in table 3.

The motor satisfies: 1.5×l=1.5×30=45+.ke= 55.5+.ltoreq (1.8-x/100) ×l= (1.8-5/100) ×30=52.5.

The motor also satisfies: n/a=80 + (25-x) 26/5= (25-5) 26/5=104.

The other structure of the motor is the same as that of embodiment 1 except for the differences shown in the present embodiment.

Table 3 part of the motor parameters of example 2

Comparative example 1

The main parameters of the motor of this comparative example are shown in table 4, compared with example 1.

The motor satisfies: 1.5×l=1.5×35=52.5×ke=55.5×l=1.8-x/100+35=58.8.

The motor also satisfies: n/a=108.ltoreq.25-x 26×sqrt (3)/5= (25-12) 26×sqrt (3)/5= 117.09.

The other structure of the motor is the same as that of embodiment 1 except for the differences shown in this comparative example.

Table 4 part of the motor parameters of comparative example 1

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Comparative example 2

The main parameters of the motor of this comparative example are shown in table 5, compared with example 1.

The motor satisfies: 1.5×l=1.5×35=52.5×ke=55.5×l=1.8-5/100+l=1.8-5/100+35=61.25.

The motor also satisfies: n/a=157 + (25-x) 26×sqrt (3)/5= (25-5) 26×sqrt (3)/5= 180.13.

The other structure of the motor is the same as that of embodiment 1 except for the differences shown in this comparative example.

Table 5 part of motor parameters of comparative example 2

Test case

The motor performance of example 1, example 2 and comparative example 1 was tested in this test example, and the results are shown in table 6.

The demagnetizing rate test process of the motor is as follows:

(1) Testing the magnetic flux at normal temperature;

(2) Placing the motor in a high-temperature environment of 130 ℃ for more than 4 hours, then introducing 22A direct current demagnetizing current into the motor, and rotating the rotor for one circle;

(3) And placing the motor in a normal temperature environment for more than 4 hours, testing the demagnetized magnetic flux, comparing with the demagnetized magnetic flux, and calculating the demagnetizing rate.

The intrinsic coercivity, remanence and motor efficiency are tested by an industry universal test method.

Table 6 motor performance of inventive example and comparative example 1

From the above results, in the embodiment 1 and the embodiment 2, the cerium content of the permanent magnet 123 is 5%, the residual magnetism=1.32t, the demagnetizing rate is not more than 1.79%, the reliability against demagnetization is good, the motor efficiency is ensured, and the purpose of reducing the cost and enhancing the efficiency is achieved.

Comparative example 1 has a high cerium content and a relatively large decrease in coercive force when the residual magnetism is relatively high, and therefore, when the same demagnetizing current is satisfied, the motor needs to be designed to have a reduced number of turns, and it is difficult to ensure the Ke value of the motor, resulting in a decrease in motor efficiency.

Comparative example 2 has a cerium content of 5%, n=157, a ke value of 62.2, and ke > (1.8-x/100) x L. At this time, N is increased by 12% compared with embodiment 1, the demagnetizing magnetic potential is increased by 12%, the demagnetizing resistance of the motor is weakened, the thickness of the permanent magnet 123 needs to be increased or the coercive force of the permanent magnet 123 needs to be increased to enhance the demagnetizing resistance, and the cost is greatly increased, contrary to the purpose of reducing the cost by using the cerium-containing permanent magnet.

In terms of cost, taking example 1 as an example, the gram weight unit price of the conventional praseodymium neodymium permanent magnet 42SH is 0.38 yuan/gram and the gram weight unit price of the permanent magnet 123 (42 SHC) containing cerium (5 wt%) is 0.279 yuan/gram, calculated according to the current price of rare earth bulk materials. The weight of each permanent magnet 123 is about 3.1g, and 16 permanent magnets are used in one motor, and the invention adopts the cerium-doped permanent magnet 123 to replace the neodymium iron boron permanent magnet in the traditional technology, so that the cost of each motor material can be reduced by about 5 yuan, the cost of the permanent magnet 123 can be reduced by 26.58 percent (0.38-0.279)/0.38) and the cost reduction effect is obvious.

As another embodiment of the present invention, there is provided a compressor including the motor of the above embodiment.

It can be appreciated that the compressor of the present embodiment, due to the use of the motor of the above embodiment, has at least all the advantages brought by the technical solution of the motor described above.

Specifically, the compressor of the present embodiment includes the motor of the above embodiment, which includes the stator 110 and the rotor 120. Wherein, the stator 110 includes a stator core, and the length of the stator core is L; the rotor 120 comprises a rotor core 121 and a plurality of permanent magnets 123 arranged on the rotor core 121, wherein the permanent magnets 123 contain cerium; the motor satisfies: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) x L; where x/100 is the mass percent of cerium contained in the permanent magnet 123, ke is the counter potential of the motor at 20℃at 1000rpm, ke is in V/krpm, and L is in mm.

In the compressor of the present embodiment, the mass percentage x/100 of cerium in the permanent magnet 123 is used, and the value range of the Ke value is adjusted by changing the length L of the stator core, so that the Ke value satisfies the following conditions: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) L, whereby the problem of the decrease in counter potential due to the use of the permanent magnet 123 containing cerium can be solved by changing the length of the stator core, thereby improving the motor efficiency. And the cost of the permanent magnet 123 containing cerium is lower than that of a conventional neodymium-iron-boron permanent magnet, so that the motor efficiency is ensured, the cost of the motor is reduced, and the cost performance of the motor is improved. Furthermore, the efficiency of the compressor can be ensured, and meanwhile, the cost of the compressor is reduced, and the cost performance of the compressor is improved.

As another embodiment of the present invention, there is provided a refrigeration apparatus including the motor or the compressor of the above embodiment.

It can be appreciated that the refrigeration equipment of the present embodiment, due to the use of the motor or the compressor of the above embodiment, has at least all the advantages brought by the technical solution of the motor or the compressor.

Further, the refrigeration apparatus of the present embodiment includes the compressor of the above embodiment, and the compressor includes the motor of the above embodiment, and the motor includes the stator 110 and the rotor 120. Wherein, the stator 110 includes a stator core, and the length of the stator core is L; the rotor 120 comprises a rotor core 121 and a plurality of permanent magnets 123 arranged on the rotor core 121, wherein the permanent magnets 123 contain cerium; the motor satisfies: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) x L; where x/100 is the mass percent of cerium contained in the permanent magnet 123, ke is the counter potential of the motor at 20℃at 1000rpm, ke is in V/krpm, and L is in mm.

In the compressor of the present embodiment, the mass percentage of cerium in the permanent magnet 123 used is x/100, and the value range of Ke value is adjusted by changing the length L of the stator core, so that Ke value satisfies: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) L, whereby the problem of the decrease in counter potential due to the use of the permanent magnet 123 containing cerium can be solved by changing the length of the stator core, thereby improving the motor efficiency. And the cost of the permanent magnet 123 containing cerium is lower than that of a conventional neodymium-iron-boron permanent magnet, so that the motor efficiency is ensured, the cost of the motor is reduced, and the cost performance of the motor is improved. Finally, the efficiency of the refrigeration equipment can be ensured, and meanwhile, the cost is reduced, and the cost performance of the refrigeration equipment is improved.

As one embodiment, the refrigeration appliance is an air conditioner.

As one embodiment, the refrigeration appliance is a refrigerator or ice bin.

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

It should be noted that other configurations of the motor, the compressor, and the refrigeration apparatus according to the embodiments of the present invention are known to those skilled in the art, and will not be described in detail herein.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present invention.

Claims (15)

1. An electric machine, comprising:

a stator including a stator core having a length L;

The rotor comprises a rotor core and a plurality of permanent magnets arranged on the rotor core, wherein cerium is contained in the permanent magnets;

The motor satisfies: 1.5 x l.ltoreq.ke.ltoreq.1.8-x/100) x L; wherein x/100 is the mass percent of cerium contained in the permanent magnet, ke is the counter potential of the motor at 20 ℃ and 1000rpm, ke is V/krpm, and L is mm.

2. The electric machine according to claim 1, characterized in that the mass percentage x/100 of cerium in the permanent magnet satisfies: x/100 is more than 0 and less than or equal to 0.1.

3. The electric machine according to claim 1, characterized in that the mass percentage x/100 of cerium in the permanent magnet satisfies: x/100 is less than or equal to 0.03 and less than or equal to 0.1.

4. A machine according to any one of claims 1 to 3, characterized in that the permanent magnet has a remanence at 20 ℃ of ≡1.30T.

5. A machine according to any one of claims 1 to 3, wherein the permanent magnets have a thickness of 1.5mm-2.5mm.

6. A motor according to any one of claims 1 to 3, wherein the length L of the stator core is: l is more than or equal to 20mm and less than or equal to 50mm.

7. A machine according to any one of claims 1 to 3, wherein the stator core is provided with a plurality of stator teeth, each of which is wound with a stator winding.

8. The electric machine of claim 7, wherein each of said stator teeth is wound with a concentrated winding, the number of turns of said concentrated winding on each of said stator teeth being N, and the number of branches of each parallel phase of said concentrated winding being a, then:

when the connection form of the concentrated winding on the stator teeth is Y-connection, N and a satisfy: n/a is less than or equal to (25-x) 26/5; when the connection form of the concentrated winding on the stator teeth is a delta connection, N and a satisfy: n/a.ltoreq.25-x.26.sqrt (3)/5.

9. A motor according to any one of claims 1 to 3, wherein the stator core is provided with a plurality of stator slots, the number of stator slots being equal to or greater than 12.

10. A machine according to any one of claims 1 to 3, wherein the outer diameter D of the rotor satisfies: d is more than or equal to 40mm and less than or equal to 80mm.

11. A motor according to any one of claims 1 to 3, wherein the permanent magnet contains praseodymium and neodymium, wherein the total mass percent of praseodymium and neodymium is 20% -32%.

12. A motor according to any one of claims 1 to 3, wherein the permanent magnet contains dysprosium and/or terbium, wherein the total mass percent of dysprosium and terbium is less than or equal to 3%.

13. A machine according to any one of claims 1 to 3, wherein the number of poles of the rotor is ≡8.

14. A compressor comprising an electric motor according to any one of claims 1 to 13.

15. A refrigeration device comprising a motor according to any one of claims 1 to 13 or a compressor according to claim 14.