Permanent magnet motor, compressor and refrigeration equipment

Abstract

The utility model provides a permanent magnet motor, a compressor and refrigeration equipment. Wherein the distance between the front ends of a pair of gap parts in the same pole of the permanent magnet motor is bs, the circumferential width of the parallel part of the tooth part is bt, the circumferential width of the front end part of the tooth part is bfe, and (bt + bfe) / 2 < = bs < = 0.98 * bfe. According to the scheme of the utility model, the situation that the magnetic flux blocking effect on the permanent magnet is too large due to the too small bs distance can be avoided, and the magnetic flux of the permanent magnet smoothly flows to the stator; and the counter electromotive force harmonic distortion rate and the cogging torque (peak-to-peak value) of the permanent magnet motor can be reduced by modulating the ratio relation of bs, bt and bfe, and the generation of torque ripple in the operation process of the permanent magnet motor is improved, so that the operation of the permanent magnet motor is more stable, the generation of noise of the permanent magnet motor is inhibited, and the stability of the compressor with the permanent magnet motor is improved. The noise of the compressor is reduced, and the comfort degree of a user using the refrigeration equipment with the compressor is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to refrigeration equipment technical field especially relates to a permanent magnet motor, compressor and refrigeration equipment. BACKGROUND

[0002] In recent years, motor technology, especially permanent magnet synchronous motor technology, has developed rapidly, and the design of motor body structure is becoming more and more novel, and the design of motor torque density and power density is becoming larger and larger, so how to improve the motor torque density has become an important task to reduce the cost of motor and improve the competitiveness of motor.

[0003] When the punching sheet of the permanent magnet motor is designed, the size of the inner diameter and the outer diameter of the second iron core, the ratio between the inner diameter and the outer diameter, the slot type and size of the magnet mounting slot, the winding method, the magnet material, the grade, the form and the amount, etc. are comprehensively considered to achieve the best performance requirement. Among them, the design of the magnet mounting slot has a great relationship with the back electromotive force, the back electromotive force harmonic distortion rate and the cogging torque of the motor. The design of the different magnet mounting slots corresponding to the different rotors can improve the motor back electromotive force, reduce the back electromotive force harmonic distortion rate and the cogging torque, and thus improve the generation of torque ripple.

[0004] And improving the torque ripple in the operation process of the permanent magnet motor can make the permanent magnet motor run more smoothly, suppress the generation of noise of the permanent magnet motor, and thus improve the stability of the compressor with the permanent magnet motor and reduce the noise of the compressor. The noise of the compressor plays a key role in the noise of the refrigeration equipment, and reducing the noise of the compressor can improve the comfort of the user using the refrigeration equipment. However, the current permanent magnet motor cannot well improve the torque ripple in the operation process, so that the noise of the compressor and the refrigeration equipment is high, which affects the user experience. UTILITY MODEL CONTENTS

[0005] An object of the utility model is to make the distance bs between the front ends of a pair of gap parts in the same pole greater than or equal to the circumferential width bt of the parallel part of the tooth part, so as to ensure that the magnetic flux of the permanent magnet flows smoothly to the stator.

[0006] A further object of the utility model is to reduce the back electromotive force harmonic distortion rate and the cogging torque of the permanent magnet motor, improve the generation of torque ripple in the operation process of the permanent magnet motor, and thus make the permanent magnet motor run more smoothly and suppress the generation of noise of the permanent magnet motor.

[0007] In particular, the utility model provides a kind of permanent magnet motor, comprising: stator and rotor, wherein rotor is arranged in the inside of stator with pre-set gap and rotates with rotating shaft,

[0008] The stator comprises: a first core and a concentrated winding coil, wherein the first core has a yoke portion in a circular ring shape, a plurality of tooth portions protruding from the yoke portion to the inner side in the radial direction, and a plurality of slots formed between adjacent tooth portions, and the coil is directly wound on the tooth portions,

[0009] The rotor comprises: a second core and a plurality of permanent magnets, wherein the second core has a plurality of magnet mounting slots arranged along the circumferential direction of the axis of the second core, the permanent magnets are embedded in the magnet mounting slots, and are alternately magnetized N-pole and S-pole, and

[0010] A plurality of pairs of gap portions are provided from both ends of the magnet mounting slots along the circumferential direction and in the direction toward the magnetic pole center line, the distance between the front ends of a pair of gap portions in the same pole is bs, the tooth portion has a parallel portion substantially parallel from the outer diameter side to the inner diameter side, and the circumferential width of the parallel portion is bt, wherein bt≤bs.

[0011] Optionally, the tooth portion further has a front end portion which is expanded in the circumferential direction from both sides of one end of the parallel portion toward the inner diameter side, and the circumferential width of the front end portion is bfe, wherein (bt+bfe) / 2≤bs≤0.98*bfe.

[0012] Optionally, the magnet mounting slot is in a linear shape or a V-shaped shape protruding toward the axis of the second core.

[0013] Optionally, the magnet mounting slot is symmetrical with respect to the magnetic pole center line; and a pair of gap portions in the same pole are symmetrical with respect to the magnetic pole center line.

[0014] Optionally, the plurality of tooth portions are arranged at equal intervals along the circumferential direction.

[0015] Optionally, the coil is provided with a concentrated winding of three-phase Y connection or delta connection formed by directly winding a predetermined number of turns on the tooth portion.

[0016] Optionally, the number of magnet mounting slots is 6 or 8.

[0017] Optionally, the first core and the second core are each formed by a laminated body of a plurality of thin plates formed of a magnetic steel plate.

[0018] The permanent magnet is a plurality of flat plates of rare earth permanent magnets mainly composed of neodymium, iron and boron, which are magnetized in an alternating manner of N-pole and S-pole.

[0019] According to another aspect of the present application, a compressor is also provided, comprising the permanent magnet motor of any one of the above.

[0020] According to still another aspect of the present application, a refrigeration device is also provided, comprising the compressor.

[0021] The permanent magnet motor of the present invention comprises: a stator and a rotor, wherein the rotor is arranged inside the stator with a preset gap and rotates together with the rotating shaft, the stator comprises: a first iron core and a concentrated winding coil, wherein the first iron core comprises: a ring-shaped yoke, a plurality of teeth protruding radially inward from the yoke, and a plurality of slots formed between adjacent teeth, the coil being directly wound on the teeth, and the rotor comprises: a second iron core and a plurality of permanent magnets, wherein the second iron core comprises: a plurality of permanent magnets arranged in a circumferential direction centered on the axis of the second iron core. A magnet mounting slot is provided, wherein the permanent magnet is embedded in the magnet mounting slot and alternately magnetized with the N pole and the S pole. A plurality of pairs of gap portions are provided from both ends of the magnet mounting slot along the circumferential direction and in the direction toward the center line of the magnetic pole. The distance between the front ends of a pair of gap portions in the same pole is bs. The tooth portion has a parallel portion that is substantially parallel from the outer diameter side to the inner diameter side. The circumferential width of the parallel portion is bt, wherein bt ≤ bs. This can avoid the bs distance being too small, which would result in excessive blocking effect on the magnetic flux of the permanent magnet, thereby ensuring that the magnetic flux of the permanent magnet flows smoothly to the stator.

[0022] Furthermore, in the permanent magnet motor of the present invention, the tooth portion also has a front end portion that expands circumferentially from both sides of one end of the parallel portion approaching the inner diameter side, and the circumferential width of the front end portion is bfe, wherein (bt+bfe) / 2≤bs≤0.98*bfe. By modulating the ratio of the distance bs between the front ends of a pair of gap portions in the same pole, the circumferential width bt of the parallel portion of the tooth portion 10, and the circumferential width bfe of the front end portion of the tooth portion, the back electromotive force harmonic distortion rate and the tooth slot torque (peak-to-peak value) of the permanent magnet motor can be effectively reduced, the generation of torque pulsation during the operation of the permanent magnet motor can be improved, the operation of the permanent magnet motor can be made more stable, the generation of noise from the permanent magnet motor can be suppressed, thereby improving the stability of the compressor having the above-mentioned permanent magnet motor, reducing the noise of the compressor, and improving the comfort of users using refrigeration equipment having the above-mentioned compressor.

[0023] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0025] Figure 1 This is an overall cross-sectional view of a permanent magnet motor having a V-shaped magnet mounting groove according to one embodiment of the present invention;

[0026] Figure 2is a partial sectional view of a magnet mounting groove of a permanent magnet motor according to an embodiment of the present application, the magnet mounting groove being V-shaped;

[0027] Figure 3 is a whole sectional view of a magnet mounting groove of a permanent magnet motor according to an embodiment of the present application, the magnet mounting groove being a straight line shape;

[0028] Figure 4 is a partial sectional view of a magnet mounting groove of a permanent magnet motor according to an embodiment of the present application, the magnet mounting groove being a straight line shape;

[0029] Figure 5 is a graph showing variation of back electromotive force of a permanent magnet motor according to distance bs according to an embodiment of the present application;

[0030] Figure 6 is a graph showing variation of back electromotive force harmonic distortion rate and cogging torque (peak-to-peak value) of a permanent magnet motor according to distance bs according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] The embodiment provides a kind of permanent magnet motor, by modulating the ratio relationship of the distance bs between the front end of a pair of gap parts in the same pole, the circumferential width bt of parallel part of tooth part 10 and the circumferential width bfe of the front end of tooth part, both can avoid that bs distance is too small, so that the magnetic flux blocking effect for permanent magnet is too large, guarantee the magnetic flux of permanent magnet to flow to stator smoothly;It can also effectively reduce the back electromotive force harmonic distortion rate and cogging torque (peak-to-peak value) of permanent magnet motor, improve the generation of torque ripple in the operation process of permanent magnet motor, so that permanent magnet motor runs more smoothly, inhibit the generation of permanent magnet motor noise, to improve the stability of compressor with the above permanent magnet motor, and reduce the noise of compressor, improve the comfort of user using the refrigeration equipment with the above compressor.

[0032] Figure 1 is a whole sectional view of a magnet mounting groove 7 of a permanent magnet motor according to an embodiment of the present application, the magnet mounting groove being V-shaped, Figure 2 is a partial sectional view of a magnet mounting groove 7 of a permanent magnet motor according to an embodiment of the present application, the magnet mounting groove being V-shaped. Figure 3 is a whole sectional view of a magnet mounting groove 7 of a permanent magnet motor according to an embodiment of the present application, the magnet mounting groove being a straight line shape, Figure 4 is a partial sectional view of a magnet mounting groove 7 of a permanent magnet motor according to an embodiment of the present application, the magnet mounting groove being a straight line shape. Figures 1 to 4 As shown in the figure, the permanent magnet motor of the embodiment can generally include: stator 1 and rotor 2.

[0033] The rotor 2 is positioned inside the stator 1 with a predetermined gap, rotating along the axis of rotation. Specifically, a rotational shaft (not shown) can be positioned along the axis of the stator 1, rotating relative to the stator 1. The cylindrical rotor 2 can then be secured to the rotational shaft. The predetermined gap between the stator 1 and the rotor 2 can be an air gap of approximately 0.3 mm to 1 mm, allowing the rotor 2 to rotate about the rotational shaft, while the rotational shaft also rotates.

[0034] It should be noted that the “axial direction” mentioned herein refers to the direction of the rotation axis of the rotor 2 , the “radial direction” refers to the radial direction of the rotor 2 , and the “circumferential direction” refers to the circumferential direction of the rotor 2 . Figure 1 The cross-sectional view of the permanent magnet motor of this embodiment is a cross-sectional view perpendicular to the rotation axis. Figure 2 、 Figure 3 、 Figure 4 The cross-sectional view of the permanent magnet motor is also a cross-sectional view in a direction perpendicular to the rotation axis. In addition, the permanent magnet motor of this embodiment can be operated as a permanent magnet motor.

[0035] In a specific embodiment, the stator 1 may include a first core 3 and concentrated winding coils 5. The first core 3 includes a circular yoke 9, a plurality of teeth 10 radially inwardly protruding from the yoke 9, and a plurality of slots 13 formed between adjacent teeth 10. The coils 5 are directly wound around the teeth 10. In a preferred embodiment, the coils 5 are directly wound around the teeth 10 with a predetermined number of turns in a three-phase Y-connection or delta-connection concentrated winding.

[0036] like Figure 1 and Figure 3 As shown, the first core 3 of the stator 1 can be cylindrical. In a preferred embodiment, the first core 3 can be formed by stacking multiple layers of thin plates made of magnetic steel sheets. The magnetic steel sheets can be silicon steel sheets. The tooth portion 10 can have a parallel portion 11 that is substantially parallel from the outer diameter side to the inner diameter side. In addition, the tooth portion 10 can also have front end portions 12a and 12b that expand circumferentially on both sides of one end of the parallel portion 11 approaching the inner diameter side. In a preferred embodiment, multiple teeth 10 are arranged at equal intervals along the circumferential direction.

[0037] In a specific embodiment, the rotor 2 may include: a second core 4 and a plurality of permanent magnets 6, wherein the second core 4 has: a plurality of magnet mounting slots 7 arranged along a circumferential direction centered on the axis 14 of the second core 4, and the permanent magnets 6 are embedded in the magnet mounting slots 7 and alternately magnetized with N poles and S poles. Figure 1 and Figure 3As shown, the second core 4 of the rotor 2 can be cylindrical. In a preferred embodiment, the second core 4 can be composed of a laminated body of multiple layers of thin plates composed of magnetic steel plates. The magnetic steel plates can be silicon steel plates.

[0038] As shown in Figure 1 and Figure 2 , the magnet mounting groove 7 can be V-shaped protruding towards the shaft center 14 of the second core 4. As shown in Figure 3 and Figure 4 , the magnet mounting groove 7 of the permanent magnet motor can also be a straight line type. For Figure 1 , Figure 2 and Figure 3 , Figure 4 , except for the shape of the magnet mounting groove 7, the structures of other parts of the permanent magnet motor can be the same.

[0039] It should be emphasized that a plurality of pairs of gap portions 8a, 8b are provided along the circumferential direction from both ends of the magnet mounting groove 7 and in the direction towards the pole center line OO', and the distance between the front ends of a pair of gap portions 8a, 8b in the same pole is bs. The front end of the gap portion 8a, 8b specifically refers to the end of the gap portion 8a, 8b close to the pole center line OO'.

[0040] In a specific embodiment, the magnet mounting groove 7 is symmetrical with respect to the pole center line OO', which can ensure that the magnetic field distribution of the rotor 2 of the permanent magnet motor is symmetrical and uniform, so that the permanent magnet motor runs smoothly. In addition, a pair of gap portions 8a, 8b in the same pole are symmetrical with respect to the pole center line OO', which can further ensure that the magnetic field distribution of the rotor 2 of the permanent magnet motor is symmetrical and uniform, so that the permanent magnet motor runs smoothly. In a specific embodiment, the number of magnet mounting grooves 7 is 6 or 8, which can make it easy and convenient to control the permanent magnet motor. For example, Figure 1 and Figure 3 The number of magnet mounting grooves 7 shown is 8.

[0041] As mentioned earlier, the tooth portion 10 has a parallel portion 11 that is approximately parallel from the outer diameter side to the inner diameter side, and the circumferential width of the parallel portion 11 is bt, and in this embodiment, bt≤bs. Figure 5 is a curve diagram of the counter electromotive force of the permanent magnet motor according to an embodiment of the present application varies with the distance bs. As shown in Figure 5As shown, with the increase of the distance bs, the gap parts 8a, 8b along the circumferential width of the second core 4 is smaller, the effect of the magnetic flux blocking of the permanent magnet 6 is smaller, and the amplitude of the back electromotive force is larger. Therefore, in order to avoid that the distance bs is too small to make the magnetic flux blocking of the permanent magnet 6 too large, the embodiment limits the minimum value of the distance bs, and sets bt≤bs, which can ensure that the magnetic flux of the permanent magnet 6 can flow smoothly to the stator 1.

[0042] The principle of the generation of the back electromotive force is based on the electromagnetic induction law. When the current flows in the conductor, the magnetic field is generated, and the changing magnetic field generates the electromotive force in the conductor. The direction of the electromotive force is opposite to the direction of the original current, and therefore it is called the back electromotive force. For example, in the motor, when the coil 5 rotates in the magnetic field, the magnetic induction lines are cut and the induced electromotive force is generated. The direction of the induced electromotive force is opposite to the direction of the current that drives the coil 5, and it plays a role in weakening the power electromotive force.

[0043] The direction of the back electromotive force is opposite to the direction of the power electromotive force, which can offset a part of the power electromotive force, reduce the current in the circuit, and hinder the rotation of the coil 5, but will not make the coil 5 rotate in the opposite direction. Therefore, the back electromotive force plays an important role in the motor control, and needs to be limited to overcome the harm of the back electromotive force, and the maximum value of the distance bs is also limited.

[0044] As mentioned above, the tooth part 10 also has the front end part 12a, 12b which is expanded in the circumferential direction from both sides of the one end of the parallel part 11 close to the inner diameter side. The circumferential width of the front end part 12a, 12b is bfe, and actually the circumferential width of the front end part 12a, 12b is bfe refers to the maximum distance between the two tooth tips of the front end of the tooth part 10 which can be measured. In a preferred embodiment, the distance bs between the front ends of a pair of gap parts 8a, 8b in the same pole is greater than or equal to the circumferential width bt of the parallel part 11 of the tooth part 10, and is less than or equal to 0.98 times the circumferential width bfe of the front end part 12a, 12b of the tooth part 10. That is, bt≤bs≤0.98*bfe.

[0045] In a specific embodiment, the circumferential width bt of the parallel part 11 of the tooth part 10 is 6.9mm, the circumferential width bfe of the front end part 12a, 12b of the tooth part 10 is 13mm, and the distance bs between the front ends of a pair of gap parts 8a, 8b in the same pole is 11mm. That is, bt=6.9mm≤bs=11mm≤0.98*bfe=0.98*13mm=12.74mm. It should be noted that the specific values of the above bt, bs and bfe are only examples and do not limit the utility model. In other embodiments, other values can be set according to actual conditions, but need to satisfy bt≤bs≤0.98*bfe.

[0046] Figure 6 is a curve graph of the back EMF harmonic distortion rate and the cogging torque (peak-peak value) of the permanent magnet motor changing with the distance bs according to an embodiment of the present application. It should be noted that, Figure 6 the solid curve in the figure reflects the trend of the back EMF harmonic distortion rate of the permanent magnet motor changing with the distance bs, and the dotted curve reflects the trend of the cogging torque (peak-peak value) of the permanent magnet motor changing with the distance bs.

[0047] The back EMF harmonic distortion rate refers to the ratio of the harmonic component in the back EMF to the fundamental component. The back EMF is an important physical quantity in the motor, representing the electromagnetic interaction between the rotor 2 and the stator 1. The magnitude of this force depends on the design of the motor, the position of the rotor 2 and the current of the stator 1. Since this force is variable, the back EMF is also variable, so the back EMF harmonic distortion rate reflects the content of the harmonic component in the back EMF. The cogging torque is the torque generated by the interaction between the permanent magnet 6 and the first core 3 of the stator 1 when the winding coil 5 of the permanent magnet motor is not energized, and is caused by the tangential component of the interaction force between the permanent magnet 6 and the tooth portion 10.

[0048] An excessively high back EMF harmonic distortion rate can cause the following hazards to the motor and the power grid: high-order harmonics can increase the loss of the motor and reduce the efficiency; can cause overvoltage; affect the communication quality and normal operation of the equipment; affect the starting and running performance of the motor. The cogging torque can cause vibration and noise of the motor, speed fluctuation, and affect the performance of the motor. In variable speed drive, when the torque ripple frequency is consistent with the mechanical resonance frequency of the stator 1 or the rotor 2, the vibration and noise caused by the cogging torque will be amplified. The existence of the cogging torque also affects the low-speed performance of the motor in the speed control system and the high-precision positioning in the position control system. Therefore, it is necessary to reasonably adjust the back EMF harmonic distortion rate and the cogging torque.

[0049] As shown in Figure 6 , with the increase of the distance bs, the back EMF harmonic distortion rate of the permanent magnet motor first sharply decreases to a trough and then sharply increases, so it can be seen that the distance bs has a relatively obvious modulation effect on the back EMF harmonic distortion rate of the permanent magnet motor, and by modulating the amplitude of the distance bs, the back EMF harmonic distortion rate of the permanent magnet motor can be effectively adjusted.

[0050] In addition, as shown in Figure 6As shown, the cogging torque (peak-peak value) of the permanent magnet motor first sharply decreases to reach a first trough, then slowly increases to reach a peak, and then slowly decreases to reach a second trough, and then sharply increases. By comparing the curves of the back EMF harmonic distortion rate and the cogging torque (peak-peak value) of the permanent magnet motor with the distance bs, it can be seen that, overall, both the back EMF harmonic distortion rate and the cogging torque (peak-peak value) first increase and then decrease with the distance bs, and the waveform coincidence degree is high.

[0051] In this way, by modulating the amplitude of the distance bs, the back EMF harmonic distortion rate and the cogging torque (peak-peak value) of the permanent magnet motor can be effectively adjusted, achieving the effect of simultaneously reducing the back EMF harmonic distortion rate and the cogging torque (peak-peak value) of the permanent magnet motor, and this is also the purpose of setting bt≤bs≤0.98*bfe in the embodiment.

[0052] In a more preferred embodiment, in order to achieve better modulation effect, the modulation range of the distance bs can be further reduced to (bt+bfe) / 2≤bs≤0.98*bfe. In this way, if the circumferential width of the parallel part 11 of the tooth part 10 is bt=6.9mm, the circumferential width of the front end part 12a, 12b of the tooth part 10 is bfe=13mm, and the distance bs between the front ends of a pair of gap parts 8a, 8b in the same pole is 11mm, (bt+bfe) / 2=9.95mm≤bs=11mm≤0.98*bfe=0.98*13mm=12.74mm can be achieved, so that the back EMF harmonic distortion rate and the cogging torque (peak-peak value) can be obtained. The amplitude is smaller.

[0053] It should be noted that the specific values of bt, bs, and bfe described above are only examples and do not limit the utility model. In other embodiments, other values can be set according to actual conditions, but (bt+bfe) / 2≤bs≤0.98*bfe must be satisfied.

[0054] By modulating the ratio relationship between the distance bs between the front ends of the gap parts 8a, 8b in the same pole and the circumferential width bt of the parallel part 11 of the tooth part 10 and the circumferential width bfe of the front end part 12a, 12b of the tooth part 10, the generation of torque ripple during the operation of the permanent magnet motor can be effectively improved, the operation of the permanent magnet motor is more stable, the generation of noise of the permanent magnet motor is suppressed, thereby improving the stability of the compressor with the above permanent magnet motor, and the noise of the compressor can be reduced, and the comfort of the user using the refrigeration equipment with the above compressor can be improved.

[0055] In summary, the permanent magnet motor of the embodiment includes: a stator 1 and a rotor 2, wherein the rotor 2 is arranged on the inner side of the stator 1 with a preset gap and rotates together with the rotating shaft, the stator 1 includes: a first iron core 3 and a concentrated winding coil 5, wherein the first iron core 3 has: a yoke part 9 with a circular ring shape, a plurality of tooth parts 10 protruding from the yoke part 9 to the radial inner side, and a plurality of insertion slots 13 formed between the adjacent tooth parts 10, and the coil 5 is directly wound on the tooth part 10, and the rotor 2 includes: a second iron core 4 and a plurality of permanent magnets 6, wherein the second iron core 4 has: a plurality of magnet mounting slots 7 arranged along the circumferential direction of the axis 14 of the second iron core 4, the permanent magnet 6 is embedded in the magnet mounting slot 7, and is alternately magnetized N pole and S pole, and a plurality of pairs of gap parts 8a, 8b are arranged from both ends of the magnet mounting slot 7 along the circumferential direction and in the direction towards the magnetic pole center line OO', the distance between the front ends of a pair of gap parts 8a, 8b in the same pole is bs, the tooth part 10 has a parallel part 11 which is substantially parallel from the outer diameter side to the inner diameter side, and the circumferential width of the parallel part 11 is bt, wherein bt≤bs, which can avoid that the bs distance is too small so that the magnetic flux blocking effect for the permanent magnet 6 is too large, and ensure that the magnetic flux of the permanent magnet 6 flows smoothly to the stator 1.

[0056] Further, the permanent magnet motor of the embodiment, the tooth part 10 further has a front end part 12a, 12b which is expanded in the circumferential direction from both sides of one end of the parallel part 11 towards the inner diameter side, and the circumferential width of the front end part 12a, 12b is bfe, wherein (bt+bfe) / 2≤bs≤0.98*bfe, by modulating the ratio relationship of the distance bs between the front ends of a pair of gap parts 8a, 8b in the same pole, the circumferential width bt of the parallel part 11 of the tooth part 10, and the circumferential width bfe of the front end part 12a, 12b of the tooth part 10, the back electromotive force harmonic distortion rate and the cogging torque (peak-to-peak value) of the permanent magnet motor can be effectively reduced, the generation of torque ripple during the operation of the permanent magnet motor is improved, the operation of the permanent magnet motor is more stable, the generation of noise of the permanent magnet motor is inhibited, thereby improving the stability of the compressor with the above permanent magnet motor, and reducing the noise of the compressor, and improving the comfort of the user using the refrigeration equipment with the above compressor.

[0057] The embodiment also provides a compressor including the permanent magnet motor of any one of the above embodiments. The types of compressor motors are generally divided into two types: induction motors and permanent magnet motors. The induction motor is a motor that works by electromagnetic induction principle, and its main characteristics are stable rotating speed, large output torque, and suitable for large load changes. The permanent magnet motor is a motor that works by magnetic field, and its main characteristics are high efficiency, fast start, small size, light weight, etc. The compressor of the embodiment uses the permanent magnet motor, which can take advantage of its high efficiency, fast start, etc.

[0058] And, the compressor of the embodiment adopts the permanent magnet motor of any one of the above embodiments, that is, the permanent magnet motor of the compressor of the embodiment, the distance between the front ends of the pair of gap portions 8a, 8b in the same pole is bs, the circumferential width of the parallel portion 11 of the tooth portion 10 is bt, and the circumferential width of the front end portion 12a, 12b is bfe, wherein (bt+bfe) / 2≤bs≤0.98*bfe.

[0059] In this way, the distance bs between the front ends of the pair of gap portions 8a, 8b in the same pole is adjusted, the circumferential width bt of the parallel portion 11 of the tooth portion 10 and the circumferential width bfe of the front end portion 12a, 12b of the tooth portion 10 are adjusted, and the ratio relationship of the three is adjusted, so that the back electromotive force harmonic distortion rate and the peak-to-peak value of the cogging torque of the permanent magnet motor are reduced, the generation of torque ripple during the operation of the permanent magnet motor is improved, the operation of the permanent magnet motor is more stable, and the generation of noise of the permanent magnet motor is inhibited. Further, the stability of the compressor with the permanent magnet motor of the embodiment can also be effectively improved, and the noise of the compressor is reduced.

[0060] The embodiment also provides a refrigeration equipment comprising the compressor with the permanent magnet motor. The noise of the compressor plays a key role in the noise of the refrigeration equipment, and by reducing the noise of the compressor, the noise of the refrigeration equipment can be effectively reduced, the comfort of the user using the refrigeration equipment with the compressor is improved, and the user experience is improved.

[0061] Those skilled in the art should understand that, without special indication, the terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "clockwise", "counterclockwise" and the like used to indicate the orientation or positional relationship in the embodiments of the utility model are only for the convenience of description and understanding of the technical scheme of the utility model, and are not intended to indicate or imply that the device or component referred to must have a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0062] The terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance or an ordered or prioritized order to the indicated technical features. Thus, the use of "first", "second", etc. to describe a particular feature can mean one or more of the features being so described and can be used either explicitly or implicitly in this specification. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined. When a certain feature is "included", "comprises" or "comprised of" a certain component, unless otherwise specifically described, it means that the feature can include the component and can further include other components, unless otherwise specifically described.

[0063] Unless otherwise defined, the terms "mounting", "connected", "connecting", "fixed", and the like, are to be construed as broad terms, for example, can be fixed connection, can be detachable connection, or integral; can be mechanical connection, can be electrical connection; can be direct connection, can be indirect connection through an intermediate medium, can be internal connection of two elements or interaction relationship between two elements, unless otherwise specifically defined. Those skilled in the art should be able to understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0064] In addition, in the description of the present embodiment, the first feature "above" or "below" the second feature can include that the first and second features are in direct contact, or can include that the first and second features are not in direct contact but are in contact through another feature between them. That is, in the description of the present embodiment, the first feature "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature "below", "under", or "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0065] In the description of the present embodiment, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does 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.

[0066] Up to now, the person skilled in the art should recognize that, although the multiple exemplary embodiments of the utility model have been shown and described in detail herein, many other variants or modifications conforming to the principles of the utility model can still be directly determined or deduced according to the content disclosed by the utility model without departing from the spirit and scope of the utility model. Therefore, the scope of the utility model should be understood and recognized as covering all these other variants or modifications.

Claims

1. A permanent magnet electric machine characterized by, Comprising: a stator and a rotor, wherein the rotor is disposed at an inner side of the stator with a predetermined gap and rotates together with a rotation axis, the stator includes a first iron core and a coil of concentrated winding, wherein the first iron core has a yoke portion of a circular ring shape, a plurality of tooth portions protruding from the yoke portion to an inner side in a radial direction, and a plurality of slots formed between adjacent tooth portions, and the coil is directly wound on the tooth portions, the rotor includes a second iron core and a plurality of permanent magnets, wherein the second iron core has a plurality of magnet mounting slots arranged in a circumferential direction of a center axis of the second iron core, the permanent magnets are embedded in the magnet mounting slots, and are alternately magnetized in N-pole and S-pole, and a plurality of pairs of gap portions are provided from both end portions of the magnet mounting slots in a circumferential direction and in a direction toward a pole center line, a distance between front ends of a pair of the gap portions in the same pole is bs, the tooth portion has a parallel portion that is substantially parallel from an outer diameter side to an inner diameter side, and a circumferential width of the parallel portion is bt, wherein bt≤bs.

2. The permanent magnet motor according to claim 1, wherein the tooth portion further has a front end portion that is expanded in a circumferential direction from both sides of one end of the parallel portion toward the inner diameter side, a circumferential width of the front end portion is bfe, and (bt+bfe) / 2≤bs≤0.98*bfe.

3. The permanent magnet motor according to claim 1, wherein the magnet mounting slot is a one-letter type or a V-letter type that is convex toward the center axis of the second iron core.

4. The permanent magnet motor according to claim 1, wherein the magnet mounting slot is symmetrical with respect to the pole center line; a pair of the gap portions in the same pole are symmetrical with respect to the pole center line.

5. The permanent magnet motor according to claim 1, wherein a plurality of the tooth portions are arranged at equal intervals in a circumferential direction.

6. The permanent magnet motor according to claim 1, wherein the coil is provided with a concentrated winding of a three-phase Y connection or a delta connection in which a predetermined number of windings are directly wound on the tooth portion.

7. The permanent magnet motor according to claim 1, wherein the number of the magnet mounting slots is six or eight.

8. The permanent magnet motor according to claim 1, wherein the first iron core and the second iron core are each composed of a laminate of a plurality of thin plates composed of a magnetic steel plate; the permanent magnet is a plurality of flat plate-shaped rare earth permanent magnets mainly composed of neodymium, iron, and boron, which are magnetized in an alternating N-pole and S-pole manner.

9. A compressor characterized by, A compressor including the permanent magnet motor according to any one of claims 1 to 8.

10. A refrigeration appliance characterized in that, A compressor including the permanent magnet motor according to claim 9.

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