Asynchronous starting permanent magnet synchronous motor

Abstract

The utility model discloses an asynchronous starting permanent magnet synchronous motor, which comprises a stator iron core, a cage type rotor and a permanent magnet structure, and a plurality of stator straight grooves for embedding a plurality of groups of stator windings are arranged on the inner side of the stator iron core at intervals; the cage type rotor comprises a rotor iron core and a plurality of spiral mounting cavities which are arranged in the rotor iron core in an extending manner; the permanent magnet structure comprises a plurality of permanent magnets which are inserted into the mounting cavities in a matched mode. A traditional skewed slot of the stator iron core is changed into a stator straight slot, automatic coil inserting is facilitated, the assembly efficiency is improved, when the motor is started, the rotor is driven to start to rotate by means of asynchronous torque generated by interaction of a stator rotating magnetic field and the cage type rotor, and when the rotating speed reaches a steady state, through interaction of the stator rotating magnetic field and permanent magnets in the rotor, the stator rotating magnetic field is driven to rotate. Electric energy is converted into mechanical energy, the permanent magnet provides a constant excitation source, no external excitation device is needed to provide excitation current, energy consumption is reduced, efficiency is improved, and power transmission is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, and particularly relates to an induction-start permanent magnet synchronous motor. Background Art

[0002] The permanent magnet synchronous motor uses permanent magnets to provide excitation, making the motor structure relatively simple, reducing processing and assembly costs, and eliminating the slip rings and brushes that are prone to problems, improving the reliability of motor operation; also, because there is no need for excitation current and no excitation loss, the efficiency and power density of the motor are improved, and it has the advantages of small volume, light weight, simple structure, high efficiency, and can achieve direct drive control.

[0003] During the operation of the permanent magnet synchronous motor, due to the interaction between the permanent magnet and the armature teeth, cogging torque will inevitably be generated, which will cause fluctuations during the operation of the permanent magnet synchronous motor, and this fluctuation will lead to electromagnetic vibration and noise of the permanent magnet synchronous motor. Therefore, in order to reduce the electromagnetic vibration and noise caused by torque fluctuation during the operation of the permanent magnet synchronous motor, it is necessary to reduce the cogging torque of the permanent magnet synchronous motor. The prior art usually uses the method of stator skewing to reduce the influence of tooth harmonics and cogging torque. According to the winding is installed in the stator skewed slot, but after the stator is set with a skewed slot, it will affect the automatic assembly of the winding. Limited by automatic wire embedding, at present, the stator winding is manually pushed obliquely into the stator skewed slot, which has high technical requirements for installers, reduces the installation efficiency of the permanent magnet motor, and is not conducive to mass production of products. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to overcome the problem in the prior art that after the stator is set with a skewed slot, it will affect the automatic assembly of the winding, and it is necessary to manually push the stator winding obliquely into the skewed slot, which reduces the installation efficiency and is not conducive to mass production of products.

[0005] To solve the above technical problems, the utility model provides an induction-start permanent magnet synchronous motor, including:

[0006] A stator structure, including a stator core and multiple groups of stator windings. The stator core has a central cavity and a plurality of stator straight slots spaced on the inner side of the stator core. The stator straight slots and the central cavity extend along the axial direction of the stator core, and multiple groups of positioning windings are distributed and embedded in the plurality of stator straight slots;

[0007] A cage rotor, arranged in a circular cavity, the cage rotor includes a rotor core and a plurality of installation cavities extending in a spiral shape inside the rotor core;

[0008] A permanent magnet structure, including a plurality of permanent magnets respectively inserted and matched in the plurality of installation cavities.

[0009] As a preferred solution, the installation cavity extends along the length direction of the rotor core, and has two open ends extending to both ends of the rotor core. The shapes of the two open ends are arc-shaped and the upper and lower parts are staggered.

[0010] As a preferred solution, four installation cavities are provided in the rotor core at uniformly spaced intervals in the circumferential direction, and four permanent magnets are provided in the four installation cavities. The cross-sectional shapes of the installation cavity and the permanent magnet are respectively arc-shaped.

[0011] As a preferred solution, the permanent magnet includes two arc-shaped ends provided in the two open ends, and a spiral connecting portion extending and connecting between the two arc-shaped ends.

[0012] As a preferred solution, the permanent magnet includes two inclined side walls inclined on both sides of the spiral connecting portion.

[0013] As a preferred solution, the arc center lines of the arc-shaped ends of the four permanent magnets extend and intersect at the axis of the rotor core.

[0014] As a preferred solution, the cage rotor includes a squirrel-cage frame disposed around the rotor core. The squirrel-cage frame includes a plurality of inclined guide bars disposed on the outer peripheral side wall of the rotor core, and two end ring structures connected to both ends of the plurality of inclined guide bars. The two end ring structures are located at both ends of the rotor core.

[0015] As a preferred solution, the squirrel-cage frame is formed by casting aluminum or copper on the rotor core.

[0016] The technical solution of the present utility model has the following advantages compared with the prior art:

[0017] 1. In the asynchronous starting permanent magnet synchronous motor provided by the present utility model, the stator core is changed from the traditional skewed slot to a straight slot, which facilitates automatic wire insertion, thereby realizing the automatic assembly of the three-phase stator winding on the stator core. The installation consistency is good, the assembly efficiency is improved, which is beneficial to mass production of products. At the same time, the rotor is designed as a cage-type rotor structure, and a spiral installation cavity is provided in the rotor core. A plurality of permanent magnets are matched and installed in the plurality of installation cavities and assembled into one body with the rotor core. By using the force generated between the excitation magnetic field of the permanent magnet and the stator rotating magnetic field, the rotation effect of the motor is realized. The specific process is as follows: The stator winding is energized with three-phase symmetric alternating current to form a rotating magnetic field. The rotating magnetic field will cause induced current and induced potential in the bars of the cage-type rotor. Relying on the asynchronous torque generated by the interaction between the stator rotating magnetic field and the cage-type rotor, the rotor starts to rotate, realizing the asynchronous start of the motor. When the speed reaches a steady state, through the interaction between the stator rotating magnetic field and the permanent magnets in the rotor, electrical energy is converted into mechanical energy, and a constant excitation source is provided by the permanent magnets, without the need for an external excitation device to provide excitation current. Therefore, energy consumption can be reduced and efficiency can be improved, thus realizing power transmission.

[0018] 2. In the asynchronous starting permanent magnet synchronous motor provided by the present utility model, four installation cavities are evenly arranged along the circumferential direction on the rotor core, so that four permanent magnets are evenly arranged in the rotor core. This design effectively reduces the permanent magnet leakage flux of the rotor and improves the utilization rate of the permanent magnet. Through the layout and optimization design of the permanent magnet structure, it is beneficial to improve the motor power and torque density.

[0019] 3. In the asynchronous starting permanent magnet synchronous motor provided by the present utility model, the permanent magnet includes two arc-shaped ends arranged at two open ends and a spiral connecting portion extending and connecting the two arc-shaped ends. This spiral structure design of the permanent magnet can effectively increase the magnetic area and torque, so that a larger torque can be generated compared with the planar and tile-shaped magnets of other motors under the same power, thereby improving the motor power.

[0020] 4. In the asynchronous starting permanent magnet synchronous motor provided by the present utility model, since the stator core adopts a straight slot design for installing the stator winding, a plurality of inclined guide bars are provided on the outer peripheral side wall of the rotor core, and the circuits of the plurality of inclined guide bars are conducted through two end ring structures. Such a design can also achieve the effects of reducing the motor tooth harmonics, cogging torque and torque ripple, improving the starting and output performance of the motor. When the motor starts, when the stator winding is energized with three-phase alternating current, a rotating magnetic field will be generated, and an induced current will be generated on the bars of the cage-type rotor, thereby generating an induced magnetic field. This induced magnetic field will interact with the stator rotating magnetic field to generate a starting torque, thereby driving the rotor to rotate and realizing the motor start. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 Structural schematic diagram of the asynchronous starting permanent magnet synchronous motor provided by the present utility model;

[0023] Figure 2 Planar structural schematic diagram of the asynchronous starting permanent magnet synchronous motor of the present utility model;

[0024] Figure 3 Planar structural schematic diagram of the stator core of the present utility model;

[0025] Figure 4 Three-dimensional structural schematic diagram of the cage rotor of the present utility model;

[0026] Figure 5 Top view of the cage rotor of the present utility model;

[0027] Figure 6 Distribution schematic diagram of the four permanent magnets of the present utility model;

[0028] Figure 7 Three-dimensional structural schematic diagram of the permanent magnet of the present utility model.

[0029] Explanation of reference numerals: 1, stator core; 11, stator straight slot; 12, middle cavity; 2, rotor core; 21, installation cavity; 3, inclined guide bar; 4, end ring structure; 5, permanent magnet; 51, arc end; 52, spiral connection part; 53, inclined side wall; a, cage rotor. Specific embodiments

[0030] The following will clearly and completely describe the technical solutions of the present utility model in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present utility model.

[0031] In the description of the present utility model, it should be noted that the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0032] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] In addition, the technical features involved in different embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0034] Embodiment

[0035] This embodiment provides an asynchronous starting permanent magnet synchronous motor as shown in Figures 1-7 and includes:

[0036] A stator structure, including a stator core 1 and multiple groups of stator windings. The stator core 1 has a central cavity 12 and a plurality of stator straight slots 11 spaced apart and arranged on the inner side of the stator core 1. The stator straight slots 11 and the central cavity 12 extend along the axial direction of the stator core 1, and multiple groups of positioning windings are distributed and installed in the plurality of stator straight slots 11;

[0037] A cage rotor a, arranged in a circular cavity. The cage rotor a includes a rotor core 2 and a plurality of installation cavities 21 extending in a spiral shape inside the rotor core 2;

[0038] A permanent magnet structure, including a plurality of permanent magnets 5 respectively inserted and matched in the plurality of installation cavities 21.

[0039] In the above embodiments, the stator core 1 is changed from the traditional skewed slots to straight stator slots 11, which facilitates automatic wire insertion, thereby realizing the automatic assembly of the three-phase stator winding on the stator core 1. The installation consistency is good, the assembly efficiency is improved, which is beneficial to the mass production of products. At the same time, the rotor is designed as a cage-type rotor a structure, and a spiral installation cavity 21 is provided in the rotor core 2. A plurality of permanent magnets 5 are matched and installed in the plurality of installation cavities 21 and assembled into one body with the rotor core 2. By using the force generated between the excitation magnetic field of the permanent magnet 5 and the stator rotating magnetic field, the rotation effect of the motor is realized. The specific process is as follows: The stator winding is energized with three-phase symmetrical alternating current to form a rotating magnetic field. The rotating magnetic field will cause induced current and induced potential in the bars of the cage-type rotor. Relying on the asynchronous torque generated by the interaction between the stator rotating magnetic field and the cage-type rotor, the rotor starts to rotate, realizing the asynchronous starting of the motor. When the speed reaches a steady state, through the interaction between the stator rotating magnetic field and the permanent magnets in the rotor, electrical energy is converted into mechanical energy, and a constant excitation source is provided by the permanent magnets, without the need for an external excitation device to provide excitation current. Therefore, energy consumption can be reduced and efficiency can be improved, thereby realizing power transmission.

[0040] The following will combine Figures 2-7 to make a detailed description of the specific structures of the permanent magnet and the rotor core:

[0041] The installation cavity 21 extends along the length direction of the rotor core 2, and it has two open ends extending to both ends of the rotor core 2. The shapes of the two open ends are arc-shaped and the upper and lower parts are staggered. The two inner side walls of the installation cavity 21 are two spiral arc surfaces. Among them, four installation cavities 21 are provided in the rotor core 2 at evenly spaced intervals in the circumferential direction. Four permanent magnets 5 that match are provided in the four installation cavities 21, that is, the permanent magnets 5 are spiral and extend along the length direction of the installation cavity. The cross-sectional shapes of the installation cavity 21 and the permanent magnet 5 are respectively arc-shaped. With this structural setting, the four permanent magnets 5 are evenly arranged in the rotor core 2 along the circumferential direction. Such a design is beneficial to reducing the permanent magnet leakage of the rotor and improving the utilization rate of the permanent magnet. Through the layout and optimized design of the permanent magnet structure, it is beneficial to improve the motor power and torque density.

[0042] Further preferably, in combination with Figure 1 、 Figures 6-7 as shown, the permanent magnet 5 includes two arc-shaped ends 51 provided at the two open ends, and a spiral connecting portion 52 extending and connecting between the two arc-shaped ends 51, and also includes two inclined side walls 53 inclined on both sides of the spiral connecting portion 52. As can be seen from the above, the permanent magnet with such a spiral structure design can effectively increase the magnetic area and increase the torque, and can generate a greater torque compared with the planar and tile-shaped magnets of other motors under the same power, thereby improving the motor power.

[0043] The arc center lines of the arc-shaped ends 51 of the four permanent magnets 5 extend and intersect at the axis of the rotor core 2. According to the design of both ends of the permanent magnet 5 to have arc-shaped ends 51 with a certain curvature, and coupled with the cross-sectional shape of the permanent magnet 5 also being an arc-shaped structure, due to the imbalance of the magnetic field magnetic circuit, with some parts being strong and some weak, this arc-shaped structure design of the permanent magnet is for the balance of the magnetic field magnetic circuit, which is beneficial to reducing magnetic pulsation and thus reducing the heat generation.

[0044] In this embodiment, the squirrel-cage rotor a includes a squirrel-cage frame arranged around the rotor core 2. This squirrel-cage frame includes a plurality of skew guide bars 3 provided on the outer peripheral side wall of the rotor core 2, and two end-ring structures 4 connected to both ends of the plurality of skew guide bars 3. The two end-ring structures 4 are located at both ends of the rotor core 2. Among them, the squirrel-cage frame is formed on the rotor core 2 by casting aluminum or copper, that is, the skew guide bars are aluminum bar structures or copper bar structures, and rotor skew slots for forming the skew guide bars 3 are provided on the outer peripheral side wall of the rotor core 2. With this structural arrangement, according to the stator core 1 being designed with straight slots for embedding the stator windings, a plurality of skew guide bars 3 are correspondingly provided on the rotor core 2, and the circuits of the plurality of skew guide bars 3 are conducted through the two end-ring structures 4. Such a design can also achieve the effects of reducing the motor tooth harmonics, cogging torque, and torque pulsation, improving the motor starting and output performance. When the motor starts, when three-phase alternating current is applied to the stator windings, a rotating magnetic field is generated, and an induced current is generated on the guide bars of the squirrel-cage rotor, thereby generating an induced magnetic field. This induced magnetic field will interact with the stator rotating magnetic field to generate a starting torque, thus driving the rotor to rotate and realizing the motor start.

[0045] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An asynchronous starting permanent magnet synchronous motor, characterized in that: include: A stator structure comprises a stator core (1) and a plurality of groups of stator windings, wherein the stator core (1) has a central cavity (12) and a plurality of stator straight slots (11) arranged at intervals inside the stator core (1), the stator straight slots (11) and the central cavity (12) extend along the axial direction of the stator core (1), and the plurality of groups of positioning windings are distributedly embedded in the plurality of stator straight slots (11); A cage rotor (a) is arranged in the middle cavity, wherein the cage rotor (a) comprises a rotor core (2) and a plurality of installation cavities (21) extending in the rotor core (2) and having a spiral shape; The permanent magnet structure comprises a plurality of permanent magnets (5) respectively matched and inserted in a plurality of installation cavities (21).

2. The asynchronous starting permanent magnet synchronous motor according to claim 1, characterized in that: The installation cavity (21) is extended along the length direction of the rotor core (2), and has two open ends extending to both ends of the rotor core (2). The two open ends are arc-shaped and the upper and lower parts are staggered.

3. The asynchronous starting permanent magnet synchronous motor according to claim 2, characterized in that: The rotor core (2) is provided with four installation cavities (21) evenly spaced in a circumferential direction, and four matching permanent magnets (5) are provided in the four installation cavities (21). The cross-sectional shapes of the installation cavities (21) and the permanent magnets (5) are respectively arc-shaped.

4. An asynchronous start permanent magnet synchronous motor according to any one of claims 1 to 3, characterized in that: The permanent magnet (5) comprises two arc-shaped ends (51) arranged in two open ends, and a spiral connection portion (52) extending and connected between the two arc-shaped ends (51).

5. The asynchronous starting permanent magnet synchronous motor according to claim 4, characterized in that: The permanent magnet (5) comprises two inclined side walls (53) arranged obliquely on both sides of the spiral connection portion (52).

6. The asynchronous start permanent magnet synchronous motor according to claim 5, characterized in that: The arc center lines of the arc-shaped ends of the four permanent magnets (5) extend and intersect with the axis of the rotor core (2).

7. The asynchronous start permanent magnet synchronous motor according to claim 1, characterized in that: The cage-type rotor (a) comprises a squirrel-cage frame arranged around a rotor core (2), the squirrel-cage frame comprising a plurality of inclined guide bars (3) arranged on the outer peripheral side wall of the rotor core (2), and two end ring structures (4) connected to both ends of the plurality of inclined guide bars (3), the two end ring structures (4) being located at both ends of the rotor core (2).

8. The asynchronous starting permanent magnet synchronous motor according to claim 7, characterized in that: The squirrel cage frame is made of cast aluminum or cast copper and is formed on the rotor core (2).

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