Electromagnetic arrangement structure and motor having the electromagnetic arrangement structure

Abstract

The present invention relates to the field of electric machines. Specifically, the present invention relates to an electromagnetic arrangement having: a stator (2) and a rotor (3) rotatable relative to the stator (2), wherein the rotor (3) is located radially inside or radially outside the stator (2), and at least one of the stator (2) and the rotor (3) has a skewed structure, characterized in that the electromagnetic arrangement further comprises compensation means for at least partially compensating a first axial force (F<subgt;ma< / subgt;) acting on the rotor (3) through the magnetic field caused by the skewed structure. The present invention also relates to an electric machine comprising such an electromagnetic arrangement. The electric machine of the present invention achieves: the additional axial force acting on the electric machine caused by skewed slots and / or skewed poles can be significantly reduced, thereby prolonging the service life of the electric machine.

Description

Technical Field

[0001] The present invention relates to an electromagnetic arrangement structure. The present invention also relates to an electric machine including such an electromagnetic arrangement structure. Background Art

[0002] Figure 1 A partial perspective view of a conventional stator 100' for a permanent magnet synchronous machine (i.e., PSM) is shown. The stator 100' includes a stator core 103', and straight slots 101' parallel to the axial direction of the machine are formed in the stator core 103'. Conductors 102' for forming a stator winding are placed in the straight slots 101'.

[0003] In such a permanent magnet synchronous machine, the presence of the teeth 104' between the straight slots 101' causes cogging torque, resulting in an undesirable torque ripple. To overcome this problem, a commonly adopted means at present is to adopt a skewing structure on the stator and / or the rotor, i.e., adopting skewed poles (not shown) on the rotor and / or adopting skewed slots 101 on the stator 100 (see Figure 2 ).

[0004] However, although skewing can effectively suppress cogging torque, it will cause an additional axial force to be applied to the machine. This can be clearly seen by comparing Figure 1 and Figure 2 . In the case of the stator 100' with straight slots 101' shown in Figure 1 , when a current I is passed through the conductor 102', according to Ampere's rule, a magnetic field perpendicular to the extension direction of the conductor 102' and thus also perpendicular to the axial direction of the machine can be generated, and this magnetic field acts on the rotor with a force F perpendicular to the axial direction of the machine a . In contrast, in the case of the stator 100 with skewed slots 101 shown in T , when a current I is passed through the conductor 102 Figure 2 , a magnetic field perpendicular to the extension direction of the conductor 102 is also generated, but since the extension direction of the skewed slots 101 is no longer parallel to the axial direction of the machine, the direction of the generated magnetic field is no longer perpendicular to the axial direction of the machine. In this case, the force F a that the magnetic field acts on the rotor has an axial component F T along the axial direction of the machine, as clearly shown by the force decomposition in ma and Figure 2 .

[0005] However, this axial component F ma is not desirable because it will ultimately be applied to the bearing 7 for rotatably supporting the machine shaft (see Figure 4) thereon, so that the bearing 7 is severely shortened in service life due to bearing a significantly increased axial force. In a permanent magnet synchronous motor, the service life of the bearing directly affects the service life of the machine, and a failure of the bearing especially during operation is particularly likely to cause a serious accident.

[0006] Therefore, it is desirable to provide a solution that can reduce or even eliminate the additional axial force caused by the skewed structure. Summary of the Invention

[0007] The object of the present invention is achieved by providing an electromagnetic arrangement structure, which has: a stator and a rotor rotatable relative to the stator, wherein the rotor is located radially inside or outside the stator, and at least one of the stator and the rotor has a skewed structure, characterized in that the electromagnetic arrangement structure further includes a compensation means for at least partially compensating a first axial force F acting on the rotor through the magnetic field caused by the skewed structure ma .

[0008] Here, it should be noted that in the present invention, the term "motor" should be broadly understood as various electromagnetic devices that achieve the conversion between electrical energy and mechanical energy based on the law of electromagnetic induction, including but not limited to: motors, generators, and motor - generator combinations.

[0009] According to an optional embodiment, the compensation means includes arranging the rotor to have an axial offset relative to the stator, so as to generate a second axial force F through the interaction between the stator magnetic field and the rotor magnetic field, which can at least partially cancel the first axial force F ma of. ma '.

[0010] According to an optional embodiment, the direction of the axial offset of the rotor relative to the stator depends on the direction of the first axial force F ma so that the generated second axial force F ma ' is opposite to the first axial force F ma .

[0011] According to an optional embodiment, the rotor has an axial offset relative to the stator in the following direction: the direction is the same as the first axial force F ma .

[0012] According to an optional embodiment, the rotor is arranged to axially extend beyond the stator at one axial end and axially retract relative to the stator at the other axial end.

[0013] According to an optional embodiment, the compensation means includes making the relative axial positions of the rotor and the stator satisfy the following formula:

[0014]

[0015] wherein, represents the axial offset vector of the rotor relative to the stator at its first axial end, represents the axial offset vector of the rotor relative to the stator at its second axial end, which is opposite to the first axial end, a positive value indicates that the rotor axially protrudes relative to the stator at the corresponding axial end, while a negative value indicates that the rotor axially retracts relative to the stator at the corresponding axial end,

[0016] wherein, includes and differ in sign and / or absolute value magnitude.

[0017] According to an optional embodiment, the rotor and the stator are arranged relative to each other in such a way that: from the and the direction pointing from the axial side related to the smaller one to the axial side related to the larger one corresponds to the direction of the first axial force F ma direction.

[0018] According to an optional embodiment, the rotor and the stator are arranged in any one of the following ways:

[0019] such that and have opposite signs;

[0020] such that and have the same sign and different absolute values;

[0021] such that and only one of them is zero.

[0022] According to an optional embodiment, the axial ends for defining the axial offset vectors and are: the natural ends of the stator and / or the rotor respectively; or the axial termination ends of at least one component of the stator and / or the rotor that affects the magnetic field.

[0023] According to another aspect of the present invention, the object of the present invention is achieved by an electric machine having the electromagnetic arrangement structure described above and a rotating shaft (6) rotationally coupled to the rotor.

[0024] The present invention achieves: it is possible to improve an existing motor in a simple manner to reduce the additional axial force acting on the motor caused by skewed slots and / or skewed poles, thereby reducing the axial load acting on the bearings, and thus extending the service life of the bearings.

[0025] From the description, the drawings, and the claims, other advantages and advantageous embodiments of the subject matter of the present invention are apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The features and advantages of the present invention can be further elaborated by the following detailed description of specific embodiments with reference to the accompanying drawings. The accompanying drawings are:

[0027] Figure 1 Showing a partial perspective view of a stator for a permanent magnet synchronous motor according to the prior art, wherein the stator has straight slots;

[0028] Figure 2 Showing a partial perspective view of a stator for a permanent magnet synchronous motor according to the prior art, wherein the stator has skewed slots;

[0029] Figure 3 Showing a schematic structural diagram of a motor according to the prior art;

[0030] Figure 4 Showing a schematic structural diagram of a motor according to an exemplary embodiment of the present invention;

[0031] Figure 5 Showing a schematic structural diagram of a motor according to another exemplary embodiment of the present invention;

[0032] Figure 6 Showing a schematic structural diagram of a motor according to still another exemplary embodiment of the present invention;

[0033] Figure 7 Showing a schematic structural diagram of a motor according to yet another exemplary embodiment of the present invention;

[0034] Figure 8 Showing a schematic structural diagram of a motor according to still another exemplary embodiment of the present invention;

[0035] Figure 9 Showing a schematic structural diagram of a motor according to another exemplary embodiment of the present invention; and

[0036] Figure 10A 、 10B 、10C, 10D, and 10E show various configurations of the rotor according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the protection scope of the present invention. In the drawings, the same or similar reference numerals refer to the same or equivalent components.

[0038] Figure 4 FIG. 4 shows a schematic structural diagram of a motor 1 according to an exemplary embodiment of the present invention. As Figure 4 shown, the motor 1 includes an annular stator 2, a rotor 3 rotatable relative to the stator 2 located within the stator 2, and a rotating shaft 6 rotationally coupled to the rotor 3. The stator 2 can generate a stator magnetic field, and the rotor 3 performs a rotational movement under the action of the stator magnetic field and further drives the rotating shaft 6 to rotate.

[0039] The stator 2 according to the present invention can, for example, have a structure as Figure 1 or Figure 2 shown. Thus, the features and details regarding the stators 100 and 100' explained above in conjunction with Figures 1-2 also apply to the stator 2 according to the present invention and will not be repeated here. In addition, the stator 2 includes a first axial end 8 and a second axial end 9 disposed opposite to the first axial end 8.

[0040] Now turning to FIG. 10, FIG. 10 shows various configurations of the rotor 3 according to the present invention. As shown in FIG. 10, the rotor 3 includes an iron core 12 and permanent magnets 13 or rotor windings (not shown) provided in or on the iron core 12. Moreover, the permanent magnets 13 and the rotor windings can be provided in or on the iron core 12 in any suitable manner. For the permanent magnets 13, they can be external to the iron core 12 as Figures 10A-10B shown, or can be internal to the iron core 12 as Figure 10C , 10D and 10E shown. In addition, the rotor 3 further includes a first axial end 10 and a second axial end 11 disposed opposite to the first axial end 10 (see Figure 4 ).

[0041] According to the present invention, at least one of the stator 2 or the rotor 3 adopts a skewed structure to reduce the cogging torque that causes torque ripple. Exemplarily, the skewed structure includes: a skewed slotting in or on the stator 2, that is, the so-called skewed slot of the stator, and / or a skewed permanent magnet or slotting in or on the rotor, that is, the so-called skewed pole or skewed slot of the rotor. Since the skewing for motors is known in the prior art, it will not be described in detail herein. And various skewed configurations and techniques known from the prior art can be applied to the motors of the present invention.

[0042] In addition, in the prior art, the stator 2 and the rotor 3 having skewed structures are always arranged axially aligned as Figure 3 shown. In this case, as explained above in connection with Figures 1-2 the skewed stator magnetic field and / or rotor magnetic field generated by the skewed structure result in an electromagnetic force F acting on the rotor 3 T that may have an unwanted additional axial component force F ma . For the sake of convenience of expression, in the context of this article, the unwanted additional axial component force on the rotor is also referred to as the first axial force. To eliminate the adverse effects brought about by the first axial force, according to the present invention, the electric machine 1 further includes compensation means for at least partially compensating the first axial force F ma .

[0043] In an exemplary embodiment, the compensation means includes arranging the rotor 3 with an axial offset relative to the stator 2. That is to say, the rotor 3 is arranged to have a certain degree of misalignment axially with respect to the stator 2. In this case, the stator magnetic field and the rotor magnetic field also axially offset relative to each other accordingly and further, through the interaction between the two, cause the stator 2 and the rotor 3 to tend to axially align with each other, that is, tend to come to Figure 3 the axially aligned position shown, thereby generating a second axial force F ma ' acting on the rotor 3 and pointing to the alignment position, and this second axial force F ma ' can be used to at least partially offset the first axial force F ma .

[0044] Furthermore, based on the first axial force F ma the relative axial position of the rotor 3 with respect to the stator 2 is determined. For this purpose, on the one hand, based on the direction of the first axial force F ma the axial offset direction of the rotor 3 with respect to the stator 2 is determined so that the second axial force F ma ' generated by the axial offset is opposite to the first axial force F ma . For this purpose, the rotor 3 is arranged to have an axial offset with respect to the stator 2 in the following direction: the direction is the same as the direction of the first axial force F ma . Specifically, in the Figure 4 shown embodiment, when the first axial force F ma borne by the rotor 3 caused by skewed slots and / or skewed poles points to the right, the rotor 3 is arranged to axially offset to the right with respect to the stator 2 to generate a left-pointing second axial force F ma ' that is opposite to the first axial force F ma ; conversely, in the Figure 5 shown embodiment, when the first axial force F maWhen pointing to the left, the rotor 3 is arranged to be axially offset to the left relative to the stator 2 to generate a second axial force F ma pointing to the right that is opposite to the first axial force F ma ’. On the other hand, based on the magnitude of the first axial force F ma , the axial offset of the rotor 3 relative to the stator 2 is determined such that the magnitude of the generated second axial force F ma ’ can offset as much as possible the first axial force F ma .

[0045] Furthermore, according to an exemplary embodiment of the present invention, an axial offset vector is defined, which is used to describe the axial offset of the rotor 3 relative to the stator 2. Specifically, the axial offset vector includes a first axial offset vector for characterizing the axial position deviation of the first axial end 10 of the rotor 3 relative to the first axial end 8 of the stator 2 and a second axial offset vector for characterizing the axial position deviation of the second axial end 11 of the rotor 3 relative to the second axial end 9 of the stator 2 wherein, being a positive value indicates that the rotor 3 axially protrudes relative to the stator 2 at the corresponding axial end, while being a negative value indicates that the rotor 3 axially retracts relative to the stator 2 at the corresponding axial end, and and the magnitudes of the absolute values respectively represent the protrusion amount or retraction amount of the rotor 3 at the corresponding axial end, and being equal to zero indicates that the rotor 3 is axially aligned with the stator 2 at the corresponding axial end.

[0046] It should be noted here that the stator axial ends 8 and 9 and the rotor axial ends 10 and 11 for defining the axial offset vector do not necessarily refer to the natural ends of the stator 2 and the rotor 3, but rather, in necessary cases, can also be understood as the axial termination ends of one or more components of the stator 2 and the rotor 3 that may affect the magnetic field. In particular, for the rotor 3, the axial termination ends of its permanent magnet 13 or rotor winding or rotor core 12 can also be regarded as the axial ends 10 and 11, and for the stator 2, the axial termination ends of its winding or core can also be regarded as the axial ends 8 and 9.

[0047] In the electric machine 1 according to the present invention, the relative axial positions of the rotor 3 and the stator 2 should satisfy the following formula:

[0048]

[0049] wherein, may include and There is a difference in sign and / or absolute value. At this time, for example, a compensating axial force F and can be generated to tend to be equal, that is, from the larger one of and to the smaller one, and the direction is the compensating axial force F ma '. Here, "larger" and "smaller" refer to the magnitude of the vector, and the sign needs to be considered.

[0050] In an exemplary embodiment, the rotor 3 is arranged such that it is closer to one of the first and second axial ends 8 and 9 of the stator 2 than to the other axial end.

[0051] In a particular embodiment, the rotor 3 is arranged such that and have opposite signs, that is, the rotor 3 is arranged to axially extend beyond the stator 2 at one axial end and axially retract relative to the stator 2 at the other axial end, as shown in Figures 4-5 . In this way, a compensating axial force F and can be generated from the side where the positive one of them is located to the side where the negative one is located, and the compensating axial force F ma ' is generated because the positive value must be greater than the negative value. Specifically, in the embodiment of Figure 4 , and At this time, the generated compensating axial force F ma ' is in the direction shown by the arrow in the figure from the positive side to the negative side; while in the embodiment of Figure 5 , and At this time, the generated compensating axial force F ma ' is in the direction shown by the arrow in the figure from side to side.

[0052] In an alternative embodiment, the rotor 3 is arranged such that and have the same sign and different absolute values, that is, the rotor 3 is arranged to axially extend beyond the stator 2 at both axial ends or axially retract relative to the stator 2 at both axial ends, but the protruding amount or retracting amount at both axial ends is different from each other, as shown in Figures 6-7 . Specifically, in the embodiment shown in Figure 6 , At this time, the generated compensating axial force F ma ' is in the direction shown by the arrow in the figure from side to side; while in Figure 7In the illustrated embodiment, At this time, the generated compensating axial force F ma ’ is in the direction shown by the arrow in the figure from side towards side.

[0053] In another alternative embodiment, the rotor 3 is arranged such that and only one of them is zero, that is, the rotor 3 is arranged with one end axially aligned with the stator 2 and not axially aligned with the stator 2 at the other end, as Figures 8-9 shown. Specifically, in the embodiment Figure 8 shown, the generated compensating axial force F ma ’ is in the direction shown by the arrow in the figure from side towards side; while in the embodiment Figure 9 shown, At this time, the generated compensating axial force F ma ’ is in the direction shown by the arrow in the figure from side towards side.

[0054] Additionally and / or alternatively, in appropriate cases, the relative positions of the respective lateral center planes of the stator 2 and the rotor 3 can also be used to define the axial offset of the rotor 3 relative to the stator 2.

[0055] It should be noted here that the compensation means according to the present invention can be applied to various types of motors, including but not limited to: permanent magnet synchronous motors and electrically excited synchronous motors.

[0056] Although some embodiments have been described, these embodiments are only presented by way of example and are not intended to limit the scope of the present invention. The appended claims and their equivalent forms are intended to cover all modifications, alternatives, and changes that fall within the scope and spirit of the present invention.

Claims

1. An electromagnetic arrangement having: a stator (2) and a rotor (3) rotatable relative to the stator (2), wherein, The rotor (3) is located radially inside or radially outside the stator (2), and at least one of the stator (2) and the rotor (3) has an offset structure, wherein the electromagnetic arrangement further comprises compensation means for at least partially compensating a first axial force (F ma ) acting on the rotor (3) by the magnetic field due to the offset structure. Among them, the compensation means includes arranging the rotor (3) with an axial offset relative to the stator (2) so as to generate a second axial force (F ma ) that can at least partially offset the first axial force (F ma ) through the interaction between the stator magnetic field and the rotor magnetic field.

2. The electromagnetic arrangement structure according to claim 1, characterized in that The direction of the axial offset of the rotor (3) relative to the stator (2) depends on the direction of the first axial force (F ma ), such that the resulting second axial force (F ma ’) is opposite to the first axial force (F ma ).

3. The electromagnetic arrangement structure according to any one of the preceding claims, characterized in that The rotor (3) has an axial offset relative to the stator (2) in the following direction: the direction is the same as that of the first axial force (F ma ).

4. The electromagnetic arrangement structure according to any one of claims 1-2, characterized in that the rotor (3) is arranged to axially extend beyond the stator (2) at one axial end and axially retract relative to the stator (2) at the other axial end.

5. The electromagnetic arrangement structure according to claim 3, characterized in that the rotor (3) is arranged to axially extend beyond the stator (2) at one axial end and axially retract relative to the stator (2) at the other axial end.

6. The electromagnetic arrangement structure according to any one of claims 1-2, 5, characterized in that the compensation means includes: making the relative axial positions of the rotor (3) and the stator (2) satisfy the following formula: wherein, represents the axial offset vector of the rotor (3) relative to the stator (2) at its first axial end (10), represents the axial offset vector of the rotor (3) relative to the stator (2) at its second axial end (11) opposite to the first axial end (10), a positive value indicates that the rotor (3) axially protrudes relative to the stator (2) at the corresponding axial end, while a negative value indicates that the rotor (3) axially retracts relative to the stator (2) at the corresponding axial end, Among them, including and differ in terms of positive / negative signs and / or absolute value magnitudes.

7. The electromagnetic arrangement structure according to claim 3, characterized in that the compensation means includes: making the relative axial positions of the rotor (3) and the stator (2) satisfy the following formula: Wherein, represents the axial offset vector of the rotor (3) relative to the stator (2) at its first axial end (10), represents the axial offset vector of the rotor (3) relative to the stator (2) at its second axial end (11) opposite to the first axial end (10), a positive value indicates that the rotor (3) axially protrudes relative to the stator (2) at the corresponding axial end, while a negative value indicates that the rotor (3) axially retracts relative to the stator (2) at the corresponding axial end, Among them, including and differ in sign and / or absolute value magnitude.

8. The electromagnetic arrangement structure according to claim 4, characterized in that the compensation means includes: making the relative axial positions of the rotor (3) and the stator (2) satisfy the following formula: wherein, represents the axial offset vector of the rotor (3) relative to the stator (2) at its first axial end (10), represents the axial offset vector of the rotor (3) relative to the stator (2) at its second axial end (11) opposite to the first axial end (10), a positive value indicates that the rotor (3) axially protrudes relative to the stator (2) at the corresponding axial end, while a negative value indicates that the rotor (3) axially retracts relative to the stator (2) at the corresponding axial end, Among them, including and differ in sign and / or absolute value magnitude.

9. The electromagnetic arrangement structure according to claim 6, characterized in that The rotor (3) and the stator (2) are arranged relative to each other in such a way that the direction pointing from the axial side associated with the smaller one of and to the axial side associated with the larger one corresponds to the direction of the first axial force (F ma ).

10. The electromagnetic arrangement structure according to claim 7 or 8, characterized in that The rotor (3) and the stator (2) are arranged relative to each other in such a way that the direction pointing from the axial side associated with the smaller one of and to the axial side associated with the larger one corresponds to the direction of the first axial force (F ma ).

11. The electromagnetic arrangement according to claim 6, characterized in that, the rotor (3) and the stator (2) are arranged in any one of the following ways: such that and have opposite plus and minus signs; such that and have the same sign and different absolute values; such that and only one of them is zero.

12. The electromagnetic arrangement according to any one of claims 7-9, characterized in that, the rotor (3) and the stator (2) are arranged in any one of the following ways: such that and have opposite signs; such that and have the same sign and different absolute values; Make and Only one of them is zero.

13. The electromagnetic arrangement according to claim 10, characterized in that, the rotor (3) and the stator (2) are arranged in any one of the following ways: such that and have opposite plus and minus signs; such that and have the same sign and different absolute values; Make and Only one of them is zero.

14. The electromagnetic arrangement structure according to claim 6, characterized in that For defining an axial offset vector and the axial ends (8, 9, 10, 11) are: the natural ends of the stator (2) and / or the rotor (3) respectively; or the axial termination ends of at least one member of the stator (2) and / or the rotor (3) respectively that affects the magnetic field.

15. The electromagnetic arrangement structure according to any one of claims 7-9, 11, 13, characterized in that For defining an axial offset vector and the axial ends (8, 9, 10, 11) are: the natural ends of the stator (2) and / or the rotor (3) respectively; or the axial termination ends of at least one member of the stator (2) and / or the rotor (3) respectively that affects the magnetic field.

16. The electromagnetic arrangement structure according to claim 10, characterized in that For defining an axial offset vector and the axial ends (8, 9, 10, 11) are: the natural ends of the stator (2) and / or the rotor (3) respectively; or the axial termination ends of at least one member of the stator (2) and / or the rotor (3) respectively that affects the magnetic field.

17. The electromagnetic arrangement structure according to claim 12, characterized in that For defining an axial offset vector and the axial ends (8, 9, 10, 11) are: the natural ends of the stator (2) and / or the rotor (3) respectively; or the axial termination ends of at least one component of the stator (2) and / or the rotor (3) respectively that affects the magnetic field.

18. An electric machine having the electromagnetic arrangement structure according to any one of claims 1-17 and a rotating shaft (6) rotationally coupled to the rotor (3).

Images