Single-phase permanent magnet motor and electrical equipment comprising same

Abstract

The invention discloses a single-phase permanent magnet motor and electrical equipment comprising the same, the single-phase permanent magnet motor comprises a stator part and a rotor part, the stator part comprises a plurality of tooth parts, magnets are arranged on the surface of the rotor part, the number of magnetic poles of the magnets is the same as that of the tooth parts, and the magnetic poles of the magnets and the tooth parts are arranged in a one-to-one correspondence manner; the outer surfaces of the magnets are all arc surfaces, the central axes corresponding to the arc surfaces deviate from the central axis of the rotor part, and in the circumferential direction of the rotor part, the distance between the outer surfaces of the magnets and the central axis of the rotor part is gradually reduced in a symmetrical mode from the symmetrical central plane position of the magnets to the two sides. When the motor operates in a grid-connected state, the waveform of no-load back electromotive force is close to a sinusoidal waveform, so that the change of electromagnetic torque is smoother, and meanwhile, the radial size corresponding to the tooth tip of the tooth part is gradually reduced along the circumferential direction of the stator part, so as to adjust the waveform phase and amplitude of the cogging torque of the motor. Therefore, the waveform change of the output torque is more stable, and the torque pulsating of the motor is reduced.

Description

Technical Field

[0001] The present invention relates to the field of motors, and in particular to a single-phase permanent magnet motor and electrical equipment comprising the same. Background Art

[0002] Compared with the traditional three-phase motor system, the single-phase permanent magnet motor system can operate in a grid-connected state, that is, the motor runs at a synchronous speed when powered by a single-phase AC power grid, and does not require a motor controller to control it. Therefore, there is no controller loss, and the motor system is more efficient under low-speed and light-load conditions.

[0003] However, in general, when a single-phase permanent magnet motor is directly powered by a single-phase AC power grid, the motor speed is the synchronous speed, and the single-phase permanent magnet motor system is running in a grid-connected state. At this time, the torque pulsation of the motor is usually greater than 200%, that is, the torque pulsation of the motor is too large, which will cause the motor to have large vibration and noise, affecting the stability of the motor operation. Most of the research focuses on the suppression of the torque pulsation of the single-phase permanent magnet motor controlled by the controller under the condition of DC power supply. There are few existing studies on the problem of large torque pulsation of the single-phase permanent magnet motor in the grid-connected state. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the torque pulsation of a single-phase permanent magnet motor is too large when the motor is directly powered by a single-phase AC power grid with a sinusoidal wave and operates in a grid-connected state, and to provide a single-phase permanent magnet motor and an electrical device containing the same.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A single-phase permanent magnet motor comprises a stator part and a rotor part, wherein the stator part comprises a plurality of teeth, and is characterized in that: a magnet is arranged on the surface of the rotor part, the number of magnetic poles of the magnet is the same as the number of the teeth, and the magnetic poles of the magnet are arranged in a one-to-one correspondence with the teeth;

[0007] The radial dimensions corresponding to the tooth tips of the multiple teeth gradually decrease along the circumferential direction of the stator part; the outer surfaces of the magnets are all arc surfaces and the center axes corresponding to the arc surfaces deviate from the center axis of the rotor part, and in the circumferential direction of the rotor part, the distance from the outer surface of the magnet to the center axis of the rotor part gradually decreases in a symmetrical manner from the symmetrical center plane position of the magnet to both sides.

[0008] In this scheme, through this arrangement, when the single-phase permanent magnet motor is in operation, the magnetic field of the magnet at the magnetic pole interacts with the armature reaction magnetic field of the stator winding, so that the motor generates output torque and realizes the conversion of mechanical energy; on this basis, the center axis corresponding to the arc surface of the magnet is deviated from the center axis set on the rotor part, that is, the center axis corresponding to the arc surface of the magnet has an eccentricity with the center axis of the rotor part, and by adjusting the distance from the outer surface of the magnet to the center axis of the rotor part, the structure of the magnet is a symmetrical structure. At this time, when the motor is running in the grid-connected state, that is, The waveform of the no-load back electromotive force of the motor can be made close to a sinusoidal waveform, thereby reducing the harmonic distortion rate of the no-load back electromotive force and making the change of the electromagnetic torque smoother. At the same time, the radial dimensions corresponding to the tooth tips of multiple teeth are gradually changed along the circumferential direction of the stator part to adjust the waveform phase and amplitude of the motor tooth torque, so that the peaks (troughs) of the tooth torque and the troughs (peaks) of the electromagnetic torque are superimposed on each other, so as to achieve a smoother waveform change of the output torque generated by the combination of the two, thereby reducing the torque pulsation of the motor, and further reducing the vibration and noise of the motor during use.

[0009] Furthermore, the magnet includes permanent magnets and ferromagnetic poles, the number of magnetic poles corresponding to the permanent magnets is the same as the number of magnetic poles corresponding to the ferromagnetic poles, the sum of the number of magnetic poles corresponding to the permanent magnets and the number of magnetic poles corresponding to the ferromagnetic poles is equal to the number of teeth, and the magnetic poles corresponding to the permanent magnets and the magnetic poles corresponding to the ferromagnetic poles are alternately arranged in sequence in the circumferential direction of the rotor part.

[0010] In the present scheme, through this arrangement, the permanent magnetism of the permanent magnet is utilized to generate a stable magnetic field, which interacts with the armature reaction magnetic field of the stator winding, thereby realizing the rotation of the motor. On this basis, permanent magnets and ferromagnetic poles are alternately arranged on the surface of the rotor part. Compared with traditional single-phase permanent magnet motors, the number of N-polarity (or S-polarity) permanent magnets can be reduced by half, the utilization rate of the permanent magnets is higher, and the cost of the motor is lower.

[0011] Furthermore, each of the permanent magnets and the ferromagnetic poles corresponds to a magnetic pole, and the permanent magnets and the ferromagnetic poles are alternately arranged in sequence in the circumferential direction of the rotor part.

[0012] In the present embodiment, when the magnetic poles of the magnet are arranged in a one-to-one correspondence with the tooth portion, through this arrangement, each permanent magnet and ferromagnetic pole is arranged corresponding to the tooth portion, and the permanent magnet and the ferromagnetic pole are arranged alternately in the circumferential direction of the rotor portion. Compared with multiple permanent magnets or multiple ferromagnetic poles corresponding to one magnetic pole, the structure or processing technology is simpler.

[0013] Furthermore, the distance between the central axis corresponding to the arc surface of the permanent magnet and the central axis of the rotor part is not less than the distance between the central axis corresponding to the arc surface of the ferromagnetic pole and the central axis of the rotor part.

[0014] In the present scheme, when the permanent magnet is the magnetomotive force source of the no-load magnetic field of the motor, through this arrangement, the eccentricity between the permanent magnet and the rotor part is greater than or equal to the eccentricity between the ferromagnetic pole and the rotor part, that is, on the surface of the rotor part, the amount of ferromagnetic pole is greater than or equal to the permanent magnet, which ensures that the amplitudes of odd-order harmonics such as the 3rd and 5th harmonics in the air gap magnetic density except the fundamental wave are as small as possible while reducing costs, further ensuring that the waveform of the no-load back electromotive force of the motor is close to a sinusoidal waveform.

[0015] Furthermore, the ferromagnetic poles and the rotor part are integrally formed.

[0016] In this solution, through this arrangement, the rotor part can be directly processed so that a part of the structure of the rotor part serves as a ferromagnetic pole, and the permanent magnets can be directly arranged on the surface of the rotor part at intervals, which is more convenient and simple in processing and manufacturing.

[0017] Furthermore, the rotor part forms a limiting groove between adjacent ferromagnetic poles, and the permanent magnet is cooperatively arranged in the limiting groove.

[0018] In the present embodiment, when the ferromagnetic poles are integrally formed with the rotor part, the ferromagnetic poles are protruded relative to the surface of the rotor part, and limiting grooves are formed between adjacent ferromagnetic poles. The permanent magnets are arranged in the corresponding limiting grooves to form alternating permanent magnets and ferromagnetic poles on the surface of the stator part, and the arrangement of the permanent magnets relative to the rotor part is also more stable, thereby increasing the reliability of the motor operation.

[0019] Furthermore, each of the magnets corresponds to a magnetic pole, and along the circumferential direction of the rotor part, the distances from the center axes corresponding to the arc surfaces of the adjacent magnets to the center axis of the rotor part are different, and the distances from the center axes corresponding to the arc surfaces of the magnets arranged at intervals to the center axis of the rotor part are the same.

[0020] In the present scheme, through this arrangement, each magnet corresponds to a magnetic pole, that is, magnets corresponding to the tooth parts are arranged on the surface of the rotor part, so that when a uniform magnetic field is formed, the distance from the center axis corresponding to the arc surface of the magnet to the center axis of the rotor part can be adjusted according to actual needs to ensure that the waveform of the no-load back electromotive force of the motor is closest to a sinusoidal waveform.

[0021] Furthermore, the stator part is arranged around the periphery of the rotor part, and the magnets are all arranged on the outer surface of the rotor part.

[0022] In the present scheme, through this arrangement, the stator part is arranged around the periphery of the rotor part to form a single-phase permanent magnet motor with an inner rotor structure, that is, the multiple teeth of the stator part are arranged to form an inner annular curved surface, and the magnets are arranged on the surface of the rotor part and face the inner annular curved surface. Under the same motor volume, compared with the single-phase permanent magnet motor with an outer rotor structure, the single-phase permanent magnet motor with an inner rotor structure allows a higher maximum speed, that is, the magnets of the rotor part do not fail under high-speed centrifugal force, and the corresponding speed is higher; in addition, the windings corresponding to the single-phase permanent magnet motor with an inner rotor structure are easier to dissipate heat.

[0023] Furthermore, radial dimensions corresponding to the tooth tips of the plurality of teeth gradually decrease along the circumferential rotation direction of the rotor portion.

[0024] In this solution, when the radial dimension corresponding to the tooth tip of each tooth portion gradually decreases along the circumference of the stator portion, the direction of the dimension reduction is further made consistent with the rotation direction of the rotor portion, so as to be more conducive to the rotation starting of the motor when the waveform of the tooth slot torque is changed.

[0025] Furthermore, surfaces corresponding to the tooth tips of the plurality of teeth are all smooth curved surfaces, and radial dimensions of the smooth curved surfaces continuously change along the circumferential direction of the stator part.

[0026] In this solution, by setting the surface corresponding to the tooth tip of the tooth portion to a smooth curved surface with a smooth transition to match the structure of the magnet on the rotor portion, the air gap formed between the magnet and the corresponding tooth portion can also change continuously, thereby making the motor run more smoothly.

[0027] Furthermore, surfaces corresponding to the tooth tips of the plurality of teeth are all stepped curved surfaces, and radial dimensions of the stepped curved surfaces change in steps along the circumferential direction of the stator part.

[0028] In this solution, compared with other settings, by setting the surface corresponding to the tooth tip of the tooth portion to a stepped surface formed by splicing multiple sections of curved surfaces, it is more conducive to processing the tooth tip of the tooth portion.

[0029] An electrical device is characterized in that the electrical device comprises the single-phase permanent magnet motor as described above.

[0030] In this solution, the single-phase permanent magnet motor as described above is applied to electrical equipment to solve the problem of large torque pulsation of the motor in the grid-connected state.

[0031] The positive and progressive effects of the present invention are:

[0032] In the present invention, the center axis corresponding to the arc surface of the magnet is deviated from the center axis of the rotor part, that is, the center axis corresponding to the arc surface of the magnet has an eccentricity with the center axis of the rotor part, and by adjusting the distance from the outer surface of the magnet to the center axis of the rotor part, the structure of the magnet is a symmetrical structure. At this time, when the motor is running in a grid-connected state, the waveform of the no-load back electromotive force of the motor can be made close to a sinusoidal waveform, thereby reducing the harmonic distortion rate of the no-load back electromotive force, making the change of the electromagnetic torque smoother. At the same time, the radial dimensions corresponding to the tooth tips of multiple teeth are gradually changed along the circumferential direction of the stator part to adjust the waveform phase and amplitude of the motor tooth torque, so that the peaks (troughs) of the tooth torque and the troughs (peaks) of the electromagnetic torque are superimposed on each other, so as to achieve a smoother waveform change of the output torque generated by the combination of the two, so as to reduce the torque pulsation of the motor, and further reduce the vibration and noise of the motor during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall cross-sectional structure of a single-phase permanent magnet motor in one embodiment of the present invention.

[0034] Figure 2 FIG. 1 is a schematic diagram of the cross-sectional structure of a rotor portion in one embodiment of the present invention.

[0035] Figure 3 Schematic diagram of the cross-sectional structure of the stator part in one embodiment of the present invention.

[0036] Figure 4 Schematic diagram of the cutting change of the tooth tip of the tooth portion in one embodiment of the present invention.

[0037] Figure 5 Schematic diagram of the torque waveform of a single-phase permanent magnet motor in one embodiment of the present invention.

[0038] Description of reference numerals:

[0039] Stator part 10

[0040] Tooth 11

[0041] Tooth body 110

[0042] Tooth tip 111

[0043] Outer ring 12

[0044] Permanent magnet 310

[0045] Ferromagnetic Pole 320

[0046] Rotor core 330

[0047] Winding 20

[0048] Shaft 340 DETAILED DESCRIPTION

[0049] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention. All other embodiments obtained by ordinary technicians in the field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0050] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “circumferential”, “radial”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0052] Example 1

[0053] The present embodiment relates to a refrigerator device, which includes a single-phase permanent magnet motor that drives a compressor. The single-phase permanent magnet motor can be switched to a grid-connected state, that is, when directly powered by a single-phase AC power grid, the motor speed is a synchronous speed, and the single-phase permanent magnet motor has a smaller torque pulsation in the grid-connected state, thereby avoiding negative effects such as large vibration and noise caused by excessive torque pulsation.

[0054] Specifically, Figure 1As shown, the single-phase permanent magnet motor includes a stator part 10 and a rotor part, the rotor part includes a permanent magnet 310, a ferromagnetic pole 320, a rotor core 330 and a rotating shaft 340, and the stator part 10 is arranged on the periphery of the rotor part, that is, the single-phase permanent magnet motor is an inner rotor structure. The stator part 10 is an integral structure composed of an outer ring part 12 and six tooth parts 11. The outer shape structure of the outer ring part 12 is similar to a circular cylindrical structure. Six tooth parts 11 extend inwardly along the radial direction of the inner wall surface of the outer ring part 12, and each tooth part 11 includes a tooth body 110 and a tooth tip 111. The tooth body 110 is connected to the inner wall surface of the outer ring part 12. The tooth tip 111 is arranged at one end of the tooth body 110 away from the outer ring part 12 and extends to both sides along the circumferential direction of the stator part 10. The inner surface of the six tooth tips 111 is surrounded to form a surface approximately cylindrical. It should be noted that, in this embodiment, the number of the teeth 11 is six. In other embodiments, the number of the teeth 11 of the stator part 10 can be adjusted as needed without any fixed restriction.

[0055] like Figure 1 and Figure 2 As shown, the winding 20 of the single-phase permanent magnet motor is wound on the tooth body 110 of the tooth portion 11, and the rotor portion includes a permanent magnet 310, a ferromagnetic pole 320, a rotor core 330 and a rotating shaft 340, wherein the overall structure of the rotor core 330 is a circular cylindrical structure, and the rotating shaft 340 is arranged inside the rotor core 330. The rotating shaft 340 passes through the inside of the rotor core 330 and is fixed to the rotor core 330, and the rotor core 330 rotates together with the rotating shaft 340 relative to the stator portion 10. Six magnets are arranged on the outer surface of the rotor core 330, and the magnets specifically include unipolar permanent magnets 310 and unipolar ferromagnetic poles 320. The number of permanent magnets 310 and ferromagnetic poles 320 are both three, that is, the number of magnetic poles corresponding to the permanent magnets 310 is the same as the number of magnetic poles corresponding to the ferromagnetic poles 320, and the number of magnetic poles corresponding to the permanent magnets 310 and the ferromagnetic poles 320 on the rotor part can be arranged one by one with the teeth 11 of the stator, and on the outer surface of the rotor core 330, the corresponding magnetic poles of the permanent magnets 310 and the ferromagnetic poles 320 on the rotor part are alternately arranged in sequence along the circumferential direction of the rotor part.

[0056] Further, such as Figure 1 As shown, the radial dimensions corresponding to the tooth tips 111 of the six teeth 11 in the stator part 10 gradually decrease along the circumferential direction of the stator part 10, that is, the radial dimensions corresponding to the inner surfaces of these tooth tips 111 gradually decrease along the circumferential direction of the stator part 10. Figure 3 As shown, the central angle θ corresponding to the tooth tip 111 of a tooth portion 11 is AB Within the range, the radial dimension of the tooth tip 111 at point A is R A , the radial dimension of the tooth tip 111 at point B is R B, the radial dimension of the tooth tip 111 is from R A to R B gradually decreases during the process. Figure 2 As shown, on the outer surface of the rotor part, the outer surfaces of these permanent magnets 310 and ferromagnetic poles 320 are arc surfaces and the central axis corresponding to the arc surface deviates from the central axis of the rotor part, and in the circumferential direction of the rotor part, the distance between the outer surfaces of these permanent magnets 310 and ferromagnetic poles 320 and the central axis of the rotor part gradually decreases in a symmetrical manner from the position of the symmetrical center plane to both sides. For details, please refer to Figure 2 As shown, the projection point O1 of the central axis corresponding to the arc surface of the permanent magnet 310 shown in the figure deviates from the projection point O of the central axis of the rotor part, and the distance O1O is the eccentricity of the permanent magnet 310, which is represented by h1. The projection point O2 of the central axis corresponding to the arc surface of the ferromagnetic pole 320 deviates from the projection point O of the central axis of the rotor part, and the distance O2O is called the eccentricity of the ferromagnetic pole 320, which is represented by h2. It should be noted that in order to ensure the normal operation of the motor, the central axes corresponding to the arc surfaces of the permanent magnet 310 and the ferromagnetic pole 320 should be parallel and deviated from the central axis of the rotor part.

[0057] Through the above arrangement, when the single-phase permanent magnet motor is in operation, first, the magnetic field of the magnet at the magnetic pole interacts with the armature reaction magnetic field of the stator winding 20, so that the motor generates output torque and realizes the conversion of mechanical energy; on this basis, the central axis corresponding to the arc surface of the magnet is deviated from the central axis set on the rotor part, that is, the central axis corresponding to the arc surface of the magnet has an eccentricity with the central axis of the rotor part, and by adjusting the distance from the outer surface of the magnet to the central axis of the rotor part, the structure of the magnet is a symmetrical structure. At this time, when the motor is running in the grid-connected state, the motor can be made The waveform of the no-load back electromotive force is close to a sinusoidal waveform, thereby reducing the harmonic distortion rate of the no-load back electromotive force and making the change of the electromagnetic torque smoother. At the same time, the radial dimensions corresponding to the tooth tips 111 of the six teeth 11 are gradually changed along the circumferential direction of the stator part 10 to adjust the waveform phase and amplitude of the motor tooth torque so that the peaks (troughs) of the tooth torque and the troughs (peaks) of the electromagnetic torque can be superimposed on each other, so as to achieve a smoother waveform change of the output torque generated by the combination of the two, thereby reducing the torque pulsation of the motor, and further reducing the vibration and noise during the use of the motor.

[0058] It should be noted that, in this embodiment, the eccentricity between the center axis corresponding to the arc surface of the magnet and the center axis of the rotor part, as well as the distance from the outer surface of the magnet to the center axis of the rotor part, is adjusted to adjust the no-load back electromotive force waveform of the motor. However, in other embodiments, other methods may be used to adjust the no-load back electromotive force waveform of the motor, such as adjusting the thickness, width, magnetization method, magnetization angle, etc. of the magnet. Similarly, in this embodiment, the waveform phase and amplitude of the motor tooth slot torque are adjusted by adjusting the radial dimensions corresponding to the tooth tip 111 of the tooth portion 11. However, in other embodiments, other methods may be used to adjust the waveform phase and amplitude of the motor tooth slot torque, such as adjusting the inner diameter of the tooth tip, the tooth tip chamfer, the stator opening auxiliary slots, the stator opening auxiliary teeth, etc.

[0059] like Figure 2 As shown, in this embodiment, the magnetic poles on the outer surface of the rotor part are alternately arranged permanent magnets 310 and ferromagnetic poles 320, and the number of magnetic poles of the permanent magnets 310 and the ferromagnetic poles 320 are matched to make them better correspond to the teeth 11 of the stator part 10. This arrangement can use the durable magnetism of the permanent magnets 310 to generate a stable magnetic field, which interacts with the armature reaction magnetic field of the stator winding 20, thereby realizing the rotation of the motor. On this basis, the permanent magnets 310 and the ferromagnetic poles 320 are alternately arranged on the surface of the rotor part. Compared with the traditional single-phase permanent magnet motor, the number of N-polarity (or S-polarity) permanent magnets 310 can be reduced by half, the utilization rate of the permanent magnets 310 is higher, and the cost of the motor is lower.

[0060] In addition, if Figure 2 As shown, in this embodiment, each permanent magnet 310 and ferromagnetic pole 320 corresponds to a magnetic pole. In this case, the permanent magnet 310 and the ferromagnetic pole 320 can be directly and alternately arranged in sequence in the circumferential direction of the rotor part, so that each permanent magnet 310 and ferromagnetic pole 320 is arranged corresponding to the tooth portion 11. However, in other embodiments, while ensuring that the magnetic poles of the magnet are arranged one by one with the tooth portion 11 of the stator part 10, two or more permanent magnets 310 can also correspond to one magnetic pole, and two or more ferromagnetic poles 320 can correspond to one magnetic pole. In this case, two or more permanent magnets 310 and two or more ferromagnetic poles 320 may be arranged continuously. In this embodiment, by arranging each permanent magnet 310 and ferromagnetic pole 320 to correspond to one magnetic pole, the structure or processing technology is simpler.

[0061] Further, such as Figure 2As shown, the distance between the center axis corresponding to the arc surface of the permanent magnet 310 and the center axis of the rotor part is not less than the distance between the center axis corresponding to the arc surface of the ferromagnetic pole 320 and the center axis of the rotor part. That is, the eccentricity between the center axis corresponding to the arc surface of the permanent magnet 310 and the center axis of the rotor part is greater than or equal to the eccentricity between the center axis corresponding to the arc surface of the ferromagnetic pole 320 and the center axis of the rotor part. In the case where the permanent magnet 310 is the magnetomotive force source of the no-load magnetic field of the motor, through this arrangement, the amount of the ferromagnetic pole 320 on the surface of the rotor part is greater than or equal to the permanent magnet 310, and the amplitude of the third, fifth and other odd harmonics in the air gap magnetic density except the fundamental wave is ensured to be as small as possible while reducing the cost, further ensuring that the no-load back electromotive force waveform of the motor is close to a sine wave.

[0062] In addition, by Figure 1 It can be known that in this embodiment, the ferromagnetic pole 320 provided on the surface of the rotor part is actually formed integrally with the rotor core 330 of the rotor part, that is, the rotor part can be directly processed so that a part of the structure of the rotor part is used as the ferromagnetic pole 320, and the permanent magnet 310 is directly arranged on the surface of the rotor part at intervals, which is more convenient and simple in processing and manufacturing. On this basis, the rotor part forms a limited groove between adjacent ferromagnetic poles 320, and the permanent magnet 310 is arranged in the limited groove, that is, the ferromagnetic pole 320 is convex relative to the surface of the rotor part, and a limited groove is formed between adjacent ferromagnetic poles 320, and the permanent magnet 310 is arranged in the corresponding limited groove to form an alternating permanent magnet 310 and ferromagnetic pole 320 on the surface of the stator part 10, and the permanent magnet 310 is arranged more firmly relative to the rotor part, thereby increasing the reliability of the motor operation.

[0063] As described above, in this embodiment, the stator part 10 is arranged around the periphery of the rotor part, and the permanent magnets 310 and the ferromagnetic poles 320 are both arranged on the outer surface of the rotor part to form a single-phase permanent magnet motor with an inner rotor structure, that is, the six teeth 11 of the stator part 10 are arranged to form an inner annular surface, and the magnets are arranged on the surface of the rotor part and face the inner annular surface. Under the same motor volume, compared with the single-phase permanent magnet motor with an outer rotor structure, the single-phase permanent magnet motor with an inner rotor structure allows a higher maximum speed, that is, the magnets of the rotor part do not fail under high-speed centrifugal force. The corresponding speed is higher; in addition, the windings corresponding to the single-phase permanent magnet motor with an inner rotor structure are easier to dissipate heat.

[0064] Further, such as Figure 1 and Figure 3As shown in FIG. 1 , the radial dimensions corresponding to the tooth tips 111 of the six teeth 11 of the stator part 10 gradually decrease along the circumferential rotation direction of the stator part 10. That is, when the radial dimensions corresponding to the tooth tips 111 of each tooth 11 gradually decrease along the circumferential direction of the stator part 10, the direction of the dimension reduction is further made consistent with the rotation direction of the rotor part, so as to be more conducive to the rotation start of the motor under the waveform of the cogging torque. Specifically, in combination with Figure 4 As shown, arc DE is the inner wall cross-section line of the tooth tip 111 of one tooth portion 11 facing the rotor portion. When the rotor rotates counterclockwise, the radial dimension corresponding to the tooth tip 111 also gradually decreases in the counterclockwise direction. The specific method is to fix point D and take point D as the center of the circle, rotate the circle where arc DE is located counterclockwise by a certain angle (the angle adjustment step can be set according to actual needs), and then extend it to intersect with the tooth tip 111 at point F, forming arc DF ( Figure 4 (indicated by dotted lines in the figure) After the arc DE and the arc DF are determined, the portion between the arc DE and the arc DF is deleted, and the remaining portion is the adjusted tooth tip 111 portion, and the tooth tip 111 will form a shape in which the radial dimension gradually decreases in the counterclockwise direction. Similarly, when the rotation direction of the rotor is clockwise, the radial dimension corresponding to the tooth tip 111 also gradually decreases in the clockwise direction. The specific method is similar and will not be repeated here. It should be understood that the arc DF is not necessarily generated based on the arc DE, and any arc DF can be generated according to actual needs.

[0065] Through the above method, the surfaces corresponding to the tooth tips 111 of the tooth portion 11 can be smooth curved surfaces, and the radial dimensions of the smooth curved surfaces continuously change along the circumferential direction of the stator portion 10 to match the structure of the magnet on the rotor portion, so that the air gap formed between the magnet and the corresponding tooth portion 11 can also change continuously, thereby making the motor run more smoothly. However, in other embodiments, the surfaces corresponding to the tooth tips 111 of these tooth portions 11 can also be set as stepped curved surfaces, and the radial dimensions of the stepped curved surfaces change in steps along the circumferential direction of the stator portion 10. Compared with other settings, by setting the surfaces corresponding to the tooth tips 111 of the tooth portion 11 as stepped curved surfaces formed by splicing multiple curved surfaces, it is more conducive to processing the tooth tips 111 of the tooth portion 11. However, it can be understood that when the radial dimension offset size is constant, the more the number of stepped curved surfaces is set, the closer the stepped curved surface is to a smooth curved surface.

[0066] Combine the following Figure 5 To further explain the adjustment of the output torque of a single-phase permanent magnet motor:

[0067] See also Figure 5As shown, T3 is the waveform of the motor output torque (indicated by a solid line in the figure), Tem3 is the waveform of the electromagnetic torque (indicated by a short dashed line in the figure), and Tc3 is the waveform of the cogging torque (indicated by a dotted line in the figure). Under normal circumstances (the tooth tip 111 of the stator part 10 is not processed), the output torque waveform of the motor is the superposition of the electromagnetic torque and the cogging torque. If the cogging torque is very small, the output torque waveform will approximately coincide with the electromagnetic torque waveform, and the difference between the maximum and minimum values ​​of the output torque divided by the average value is the percentage of the torque pulsation, that is, under normal circumstances, the percentage of the torque pulsation of the motor is about 200%.

[0068] In this embodiment, firstly, the eccentricity between the center axis corresponding to the arc surface of the magnet and the center axis of the rotor part, as well as the distance from the outer surface of the magnet to the center axis of the rotor part, is adjusted so that the waveform of the no-load back electromotive force is close to a sinusoidal waveform, thereby reducing the harmonic distortion rate of the no-load back electromotive force and making the waveform change of the electromagnetic torque smoother. Furthermore, the waveform phase and amplitude of the motor tooth torque are adjusted by adjusting the radial dimensions corresponding to the tooth tip 111 of the tooth part 11, so that the peaks (troughs) of the tooth torque and the troughs (peaks) of the electromagnetic torque are superimposed on each other, so as to achieve a smoother waveform change of the output torque generated by the combination of the two, thereby reducing the torque pulsation of the motor, and further reducing the vibration and noise during the use of the motor. Figure 5 It can be seen that in order to minimize the fluctuation amplitude of the torque pulsation, the phase difference between the electromagnetic torque and the cogging torque can be made 90 degrees, that is, the peak of the cogging torque corresponds to the trough of the current electromagnetic torque of the motor, and the trough of the cogging torque corresponds to the peak of the current electromagnetic torque of the motor. This will better superimpose the peaks of the two waveforms with the corresponding troughs, so as to achieve a relatively smooth waveform of the torque of the motor superimposed by the two.

[0069] In this embodiment, by applying the above-mentioned single-phase permanent magnet motor to the refrigerator device, because the efficiency requirements of the compressor motor system in the refrigerator device are relatively high, and the refrigerator device compressor motor runs under low-speed and light-load conditions most of the time, compared with the traditional three-phase motor system, the single-phase permanent magnet motor can run in a grid-connected state, and the motor runs at a synchronous speed when powered by a single-phase AC power grid, and does not need a motor controller to control it. Therefore, there is no loss of the controller, and the efficiency of the motor system is higher under low-speed and light-load conditions. At the same time, the torque pulsation of the motor in the running state is small, with less vibration and noise. However, the single-phase permanent magnet motor can also be set in other electrical equipment with similar working conditions.

[0070] Example 2

[0071] This embodiment also provides a refrigerator device, which is also provided with a single-phase permanent magnet motor. The single-phase permanent magnet motor is basically similar to the single-phase permanent magnet motor in Embodiment 1, except that the magnetic poles arranged on the outer surface of the rotor part are different. In this embodiment, permanent magnets are arranged on the outer surface of the rotor part, and the permanent magnets are used to generate a stable magnetic field, which interacts with the armature reaction magnetic field of the stator winding to achieve the rotation of the motor. Specifically, the number of magnetic poles of the permanent magnet is the same as the number of teeth, and the magnetic poles of the permanent magnet are arranged one by one corresponding to the teeth of the stator part, which can also achieve the effect of reducing the torque pulsation of the motor.

[0072] On this basis, each permanent magnet corresponds to a magnetic pole. If the materials of all the permanent magnets are the same, then along the circumferential direction of the rotor part, the distances from the center axes corresponding to the arc surfaces of all the permanent magnets to the center axis of the rotor part are the same. However, if the materials of the permanent magnets are different, the distances from the center axes corresponding to the arc surfaces of each permanent magnet to the center axis of the rotor part are also different.

[0073] Through this arrangement, each permanent magnet corresponds to a magnetic pole, that is, permanent magnets corresponding to the tooth parts are arranged on the surface of the rotor part, so that when a uniform magnetic field is formed, the distance from the center axis corresponding to the arc surface of the permanent magnet to the center axis of the rotor part can be adjusted according to actual needs to ensure that the waveform of the no-load back electromotive force of the motor is closest to a sinusoidal waveform, which is more conducive to reducing the torque pulsation of the motor.

[0074] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A single-phase permanent magnet motor, comprising a stator portion and a rotor portion, wherein the stator portion comprises a plurality of teeth, characterized in that: A magnet is arranged on the surface of the rotor part, the number of magnetic poles of the magnet is the same as the number of the teeth, and the magnetic poles of the magnet are arranged in a one-to-one correspondence with the teeth; The radial dimensions corresponding to the tooth tips of the multiple teeth gradually decrease along the circumferential direction of the stator part; the outer surfaces of the magnets are all arc surfaces and the center axes corresponding to the arc surfaces deviate from the center axis of the rotor part, and in the circumferential direction of the rotor part, the distance from the outer surface of the magnet to the center axis of the rotor part gradually decreases in a symmetrical manner from the symmetrical center plane position of the magnet to both sides.

2. The single-phase permanent magnet motor according to claim 1, characterized in that: The magnet includes permanent magnets and ferromagnetic poles, the number of magnetic poles corresponding to the permanent magnets is the same as the number of magnetic poles corresponding to the ferromagnetic poles, the sum of the number of magnetic poles corresponding to the permanent magnets and the number of magnetic poles corresponding to the ferromagnetic poles is equal to the number of teeth, and the magnetic poles corresponding to the permanent magnets and the magnetic poles corresponding to the ferromagnetic poles are alternately arranged in sequence in the circumferential direction of the rotor part.

3. The single-phase permanent magnet motor according to claim 2, characterized in that: Each of the permanent magnets and the ferromagnetic poles corresponds to a magnetic pole, and the permanent magnets and the ferromagnetic poles are alternately arranged in sequence in the circumferential direction of the rotor part.

4. The single-phase permanent magnet motor according to claim 3, characterized in that: The distance between the central axis corresponding to the arc surface of the permanent magnet and the central axis of the rotor part is not less than the distance between the central axis corresponding to the arc surface of the ferromagnetic pole and the central axis of the rotor part.

5. The single-phase permanent magnet motor according to claim 3, characterized in that: The ferromagnetic poles and the rotor part are integrally formed.

6. The single-phase permanent magnet motor according to claim 3, characterized in that: The rotor part forms a limiting groove between adjacent ferromagnetic poles, and the permanent magnet is cooperatively arranged in the limiting groove.

7. The single-phase permanent magnet motor according to claim 1, characterized in that: Each of the magnets corresponds to a magnetic pole. Along the circumferential direction of the rotor part, the distances from the center axes corresponding to the arc surfaces of the adjacent magnets to the center axis of the rotor part are different, while the distances from the center axes corresponding to the arc surfaces of the magnets arranged at intervals to the center axis of the rotor part are the same.

8. The single-phase permanent magnet motor according to any one of claims 1 to 7, characterized in that: The stator part is disposed around the periphery of the rotor part, and the magnets are all disposed on the outer surface of the rotor part.

9. The single-phase permanent magnet motor according to claim 8, characterized in that: The radial dimensions corresponding to the tooth tips of the plurality of tooth portions gradually decrease along the circumferential rotation direction of the rotor portion.

10. The single-phase permanent magnet motor according to claim 8, characterized in that: Surfaces corresponding to the tooth tips of the plurality of tooth portions are all smooth curved surfaces, and radial dimensions of the smooth curved surfaces continuously change along the circumferential direction of the stator portion.

11. The single-phase permanent magnet motor according to claim 8, characterized in that: Surfaces corresponding to the tooth tips of the plurality of tooth portions are all step-curved surfaces, and radial dimensions of the step-curved surfaces change in steps along the circumferential direction of the stator portion.

12. An electrical device, characterized in that: The electrical equipment comprises a single-phase permanent magnet motor as described in any one of claims 1-11.

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