CN114301231A - Electromagnetic arrangement and electric machine having an electromagnetic arrangement - Google Patents

Abstract

The invention relates to the field of motors. In particular, the 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 skew structure, characterized in that the electromagnetic arrangement further comprises compensation means for at least partially compensating a first axial force (F) acting on the rotor (3) by a magnetic field caused by the skew structure_ma). The invention also relates to an electric machine comprising such an electromagnetic arrangement. The motor of the invention realizes that: can remarkably reduce the free inclinationThe additional axial force on the motor caused by the slots and/or the skewed poles, thereby extending the useful life of the motor.

Description

Electromagnetic arrangement structure and motor with electromagnetic arrangement structure

technical field

The present invention relates to an electromagnetic arrangement structure. The invention also relates to an electric machine comprising such an electromagnetic arrangement.

Background technique

Figure 1 shows a partial perspective view of a conventional stator 100' for a permanent magnet synchronous machine (i.e., PSM). The stator 100' includes a stator iron core 103', and the stator iron core 103' is provided with a straight slot 101' parallel to the axial direction of the motor. The wires 102' used to form the stator windings are placed in the straight slots 101'.

In such a permanent magnet synchronous motor, the presence of the straight slots 101' and the teeth 104' between the straight slots can cause cogging torque to cause undesired torque ripple. In order to overcome this problem, the currently commonly used means is to use a skew structure on the stator and/or rotor, that is, to use inclined poles (not shown) on the rotor and/or to use inclined slots 101 on the stator 100 (see FIG. 2).

However, although skewing is effective in suppressing cogging torque, it causes additional axial forces to be applied to the motor. This can be clearly seen by comparing Figures 1 and 2. In the case of the stator 100 ′ with straight slots 101 ′ shown in FIG. 1 , when the conductor 102 ′ is supplied with a current I _a , according to Ampere’s law, a direction of extension perpendicular to the conductor 102 ′ and thus also A magnetic field perpendicular to the motor axis, which acts on the rotor with a force _FT perpendicular to the motor axis. In contrast, in the case of the stator 100 with the inclined slot 101 shown in FIG. 2, when the wire 102 is supplied with the current I _a , a magnetic field perpendicular to the extension direction of the wire 102 is also generated, but due to the inclined slot The extending direction of 101 is no longer parallel to the motor axis, so the direction of the generated magnetic field is no longer perpendicular to the motor axis. In this case, the force F _T of the magnetic field on the rotor has an axial component F _ma along the axial direction of the motor, as clearly shown by the decomposition of the force in FIG. 2 .

However, this axial component force F _ma is not expected because it will eventually be exerted on the bearing 7 (see FIG. 4 ) for rotatably supporting the motor shaft, so that the bearing 7 is subjected to a significantly increased axial The service life is severely shortened due to the force. In the permanent magnet synchronous motor, the life of the bearing directly affects the life of the machine, and the failure of the bearing, especially during operation, may lead to serious accidents.

Therefore, it would be desirable to provide a solution that reduces, or even eliminates, the additional axial force caused by the deflected structure.

SUMMARY OF THE INVENTION

The object of the present invention is achieved by providing an electromagnetic arrangement having a stator and a rotor rotatable relative to the stator, wherein the rotor is located radially inward or radially outward of the stator , and at least one of the stator and the rotor has a skew structure, characterized in that the electromagnetic arrangement further includes compensation means for at least partially compensating for the skew structure caused by the skew structure of the first axial force F _ma acting on the rotor by the magnetic field.

It should be noted here that, in the present invention, the term "electric machine" should be broadly understood as various electromagnetic devices that realize the conversion of electrical energy and mechanical energy according to the law of electromagnetic induction, including but not limited to: electric motors, generators and electric- Generator combination machine.

According to an optional embodiment, the compensating means comprises: arranging the rotor with an axial offset relative to the stator, so as to at least partially cancel the first A second axial force F _ma ' of an axial force F _ma .

According to an alternative embodiment, the direction in which the rotor is axially offset relative to the stator depends on the direction of the first axial force F _ma , such that the second axial force F _ma ′ generated is the same as the The first axial force F _ma is reversed.

According to an alternative embodiment, the rotor has an axial offset relative to the stator in a direction co-directional with the first axial force F _ma .

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

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

表示所述转子在其第一轴向端处相对所述定子的轴向偏移矢量，

表示所述转子在它的与所述第一轴向端相反设置的第二轴向端处相对所述定子的轴向偏移矢量，

为正值则表示所述转子在相应的轴向端处相对于所述定子轴向突出，而

为负值则表示所述转子在相应的轴向端处相对于所述定子轴向缩回，in,

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 disposed opposite the first axial end,

A positive value means that the rotor protrudes axially relative to the stator at the corresponding axial end, while

A negative value means that the rotor is axially retracted relative to the stator at the corresponding axial end,

包括

和

在正负号和/或绝对值大小上存在差别。in,

include

and

There are differences in sign and/or absolute magnitude.

和

中的小的那个所涉及的轴向侧指向大的那个所涉及的轴向侧的方向对应于所述第一轴向力F_ma的方向。According to an alternative embodiment, the rotor and the stator are arranged relative to each other in such a way that from

and

The direction in which the concerned axial side of the smaller one points to the concerned axial side of the larger one corresponds to the direction of said first axial force F _ma .

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

和

具有相反的正负号；make

and

have opposite signs;

和

具有相同的正负号和不同的绝对值；make

and

have the same sign and different absolute values;

和

中的仅一个为零。make

and

Only one of them is zero.

和

的轴向端是：定子和/或转子各自的自然末端；或定子和/或转子各自的影响磁场的至少一个构件的轴向终止端。According to an alternative embodiment, for defining an axial offset vector

and

The axial ends of are: the respective natural ends of the stator and/or the rotor; or the axially terminating ends of the respective at least one component of the stator and/or the rotor that affects the magnetic field.

According to another aspect of the invention, the object of the invention is achieved by an electric machine having the electromagnetic arrangement described above and a rotating shaft (6) coupled in rotation with said rotor.

The present invention realizes that the existing motor can be modified in a simple way to reduce the additional axial force acting on the motor caused by the inclined slot and/or the inclined pole, thereby reducing the axial load acting on the bearing , thereby extending the service life of the bearing.

Other advantages and advantageous embodiments of the inventive subject matter will be apparent from the description, drawings and claims.

Description of drawings

Further features and advantages of the present invention can be further elucidated by the following detailed description of specific embodiments with reference to the accompanying drawings. The attached drawings are:

Figure 1 shows a partial perspective view of a stator for a permanent magnet synchronous machine according to the prior art, wherein the stator has straight slots;

Figure 2 shows a partial perspective view of a stator for a permanent magnet synchronous machine according to the prior art, wherein the stator is provided with inclined slots;

FIG. 3 shows a schematic structural diagram of a motor according to the prior art;

FIG. 4 shows a schematic structural diagram of a motor according to an exemplary embodiment of the present invention;

FIG. 5 shows a schematic structural diagram of a motor according to another exemplary embodiment of the present invention;

FIG. 6 shows a schematic structural diagram of a motor according to yet another exemplary embodiment of the present invention;

FIG. 7 shows a schematic structural diagram of a motor according to yet another exemplary embodiment of the present invention;

FIG. 8 shows a schematic structural diagram of a motor according to a further exemplary embodiment of the present invention;

FIG. 9 shows a schematic structural diagram of a motor according to another exemplary embodiment of the present invention; and

Figures 10A, 10B, 10C, 10D and 10E illustrate various configurations of rotors according to the present invention.

Detailed ways

In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying 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 numbers refer to the same or equivalent parts.

FIG. 4 shows a schematic structural diagram of the motor 1 according to an exemplary embodiment of the present invention. As shown in FIG. 4 , the motor 1 includes an annular stator 2 , a rotor 3 located in the stator 2 and rotatable relative to the stator 2 , and a rotating shaft 6 rotatably coupled to the rotor 3 . The stator 2 can generate a stator magnetic field, and the rotor 3 performs a rotational motion under the action of the stator magnetic field, thereby driving the rotating shaft 6 to rotate.

The stator 2 according to the present invention may have, for example, the configuration shown in FIG. 1 or FIG. 2 . Thus, the features and details of the stators 100 and 100' explained above in connection with Figs. 1-2 are also applicable to the stator 2 according to the present invention and will not be repeated here. Furthermore, the stator 2 comprises a first axial end 8 and a second axial end 9 arranged opposite the first axial end 8 .

Turning now to Figure 10, Figure 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) disposed in or on the iron core 12 . Also, the permanent magnets 13 and rotor windings may be provided in or on the core 12 in any suitable manner. The permanent magnets 13 may be externally placed relative to the iron core 12 as shown in FIGS. 10A-10B , or may be built in relative to the iron core 12 as shown in FIGS. 10C , 10D and 10E. Furthermore, the rotor 3 also comprises a first axial end 10 and a second axial end 11 arranged opposite the first axial end 10 (see FIG. 4 ).

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 which causes the torque ripple. Illustratively, the skewed structures include skewed slots in or on the stator 2, so-called skewed slots of the stator, and/or skewed permanent magnets or slots in or on the rotor, so-called skewed slots. The inclined pole or slot of the rotor. Since the deflection for the motor is known in the prior art, it will not be described in detail here. Also, various skew configurations and techniques known from the prior art can be applied to the motor of the present invention.

Furthermore, in the prior art, the stator 2 and the rotor 3 with a skewed structure are always arranged axially aligned as shown in FIG. 3 . In this case, as explained above in connection with Figures 1-2, the electromagnetic force _FT acting on the rotor 3 due to the skewed stator and/or rotor magnetic fields produced by the skewed structure may have undesirable additional The axial component force F _ma . For convenience of expression, in the context of this document, the undesired additional axial component force on the rotor is also referred to as the first axial force. In order to eliminate the adverse effects brought by the first axial force, according to the present invention, the electric machine 1 further comprises compensation means for at least partially compensating for the first axial force F _ma .

In an exemplary embodiment, the compensation means comprises: arranging the rotor 3 with an axial offset relative to the stator 2 . That is, the rotor 3 is arranged to have a certain degree of misalignment with the stator 2 in the axial direction. In this case, the stator magnetic field and the rotor magnetic field are accordingly also axially offset with respect to each other and thus, through the interaction between the two, the stator 2 and the rotor 3 tend to be axially aligned with each other, ie tend to The axial alignment position shown in FIG. 3 is reached, resulting in a second axial force F _ma ′ acting on the rotor 3 directed towards the alignment position, which second axial force F _ma ′ can be used to at least partially The first axial force F _ma is counteracted.

Further, the relative axial position of the rotor 3 and the stator 2 is determined based on the first axial force F _ma . To this end, on the one hand, the direction of the axial offset of the rotor 3 relative to the stator 2 is determined based on the direction of the first axial force F _ma , such that the second axial force F generated by said axial offset _ma ' is opposite to the first axial force F _ma . For this purpose, the rotor 3 is arranged with an axial offset relative to the stator 2 in a direction co-directional with the direction of the first axial force F _ma . Specifically, in the embodiment shown in FIG. 4 , the rotor 3 is arranged relative to the stator in the case where the first axial force F _ma that the rotor 3 is subjected to, caused by the inclined slots and/or inclined poles, points to the right 2 is axially offset to the right to generate a second axial force F _ma ′ directed to the left opposite to the first axial force F _ma ; on the contrary, in the embodiment shown in FIG. With the first axial force F _ma directed to the left, the rotor 3 is arranged to be offset axially to the left relative to the stator 2 to generate a second axial force directed to the right opposite to the first axial force F _ma Force F _ma '. On the other hand, the amount of axial offset of the rotor 3 relative to the stator 2 is determined based on the magnitude of the first axial force F _ma , so that the magnitude of the generated second axial force F _ma ′ can offset as much as possible drop the first axial force F _ma .

被定义，其用于描述转子3相对于定子2的轴向偏移。具体而言，轴向偏移矢量

包括用于表征转子3的第一轴向端10相对定子2的第一轴向端8的轴向位置偏差的第一轴向偏移矢量

和用于表征转子3的第二轴向端11相对定子2的第二轴向端9的轴向位置偏差的第二轴向偏移矢量

其中，

为正值则表示转子3在相应的轴向端处相对于定子2轴向突出，而

为负值则表示转子3在相应的轴向端处相对于定子2轴向缩回，且

和

的绝对值的大小分别表示转子3在相应的轴向端的突出量或缩回量，并且，

等于零则表示转子3在相应的轴向端处与定子2是轴向对齐的。Further, according to an exemplary embodiment of the present invention, the 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

comprising a first axial offset vector 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 characterizing the axial positional deviation of the second axial end 11 of the rotor 3 relative to the second axial end 9 of the stator 2

in,

A positive value means that the rotor 3 protrudes axially relative to the stator 2 at the corresponding axial end, while

A negative value means that the rotor 3 is axially retracted relative to the stator 2 at the corresponding axial end, and

and

The magnitude of the absolute value of , respectively represents the amount of protrusion or retraction of the rotor 3 at the corresponding axial end, and,

Equal to zero means that the rotor 3 is axially aligned with the stator 2 at the respective axial ends.

的定子轴向端8和9以及转子轴向端10和11不应当必然指代的是定子2和转子3的自然末端，而是，在必要的情况下也可以理解为定子2和转子3的可能影响磁场的构件之一或多个的轴向终止端。尤其，对于转子3，其永磁体13或转子绕组或转子铁芯12的轴向终止端也可以视作所述轴向端10和11，对于定子2，其绕组或铁芯的轴向终止端也可以视作所述轴向端8和9。It should be noted here that it is used to define the axial offset vector

The stator axial ends 8 and 9 and the rotor axial ends 10 and 11 should not necessarily refer to the natural ends of the stator 2 and the rotor 3, but, where necessary, can also be understood as the The axially terminating end of one or more of the components that may affect the magnetic field. In particular, for the rotor 3, the axial termination ends of its permanent magnets 13 or rotor windings 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 windings or cores Said axial ends 8 and 9 may also be considered.

In the motor 1 according to the present invention, the relative axial positions of the rotor 3 and the stator 2 should satisfy the following formula:

可包括

和

在正负号和/或绝对值大小上存在差别。此时，可以产生例如使

和

趋于均等、即从

和

中的大的那个指向小的那个的补偿轴向力F_ma’，此处的“大”和“小”指的是矢量的大小，需要考虑正负号。in,

can include

and

There are differences in sign and/or absolute magnitude. In this case, it is possible to generate, for example,

and

tend to be equal, that is, from

and

The larger one of these points to the compensation axial force F _ma ' of the smaller one, where "large" and "small" refer to the magnitude of the vector, and the sign needs to be considered.

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

和

具有相反的正负号，也即，转子3布置成在一轴向端轴向地延伸超过定子2，而在另一轴向端相对于定子2轴向缩回，如图4-5所示。采用这种方式，可以产生从

和

中的正的那个所在的侧指向负的那个所在的侧的补偿轴向力F_ma’，因为正值必然大于负值。具体而言，在图4的实施例中，

且

此时，所产生的补偿轴向力F_ma’的方向如图中箭头示出的那样从正的

侧指向负的

侧；而在图5的实施例中，

且

此时，所产生的补偿轴向力F_ma’的方向如图中箭头示出的那样从

侧指向

侧。In a particular embodiment, the rotor 3 is arranged such that

and

With opposite signs, that is, the rotor 3 is arranged to extend axially beyond the stator 2 at one axial end and retract axially relative to the stator 2 at the other axial end, as shown in Figures 4-5 . In this way, it is possible to generate

and

The compensated axial force F _ma ' on the side where the positive one is pointing to the negative one, because the positive value is necessarily greater than the negative value. Specifically, in the embodiment of FIG. 4,

and

At this time, the direction of the generated compensating axial force F _ma ' changes from the positive

side pointing negative

side; while in the embodiment of Figure 5,

and

At this time, the direction of the generated compensating axial force F _ma ' is shown by the arrow in the figure from

side pointing

side.

和

具有相同的正负号和不同的绝对值，也即，转子3布置成在两轴向端都轴向地延伸超过定子2或都相对于定子2轴向缩回，但是在两轴向端的突出量或缩回量彼此不同，如图6-7所示。具体而言，在图6所示的实施例中，

此时，所产生的补偿轴向力F_ma’的方向如图中箭头示出的那样从

侧指向

侧；而在图7所示的实施例中，

此时，所产生的补偿轴向力F_ma’的方向如图中箭头示出的那样从

侧指向

侧。In an alternative embodiment, the rotor 3 is arranged such that the

and

have the same sign and different absolute values, i.e. the rotor 3 is arranged to extend axially beyond the stator 2 at both axial ends or both axially retract relative to the stator 2, but protrude at both axial ends The amount or retraction amount is different from each other, as shown in Figure 6-7. Specifically, in the embodiment shown in FIG. 6,

At this time, the direction of the generated compensating axial force F _ma ' is shown by the arrow in the figure from

side pointing

side; while in the embodiment shown in Figure 7,

At this time, the direction of the generated compensating axial force F _ma ' is shown by the arrow in the figure from

side pointing

side.

和

中的仅一个为零，也即，转子3布置成一端与定子2轴向对齐，而在另一端与定子2没有轴向对齐，如图8-9所示。具体而言，在图8所示的实施例中，

所产生的补偿轴向力F_ma’的方向如图中箭头示出的那样从

侧指向

侧；而在图9所示的实施例中，

此时，所产生的补偿轴向力F_ma’的方向如图中箭头示出的那样从

侧指向

侧。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 to be axially aligned with the stator 2 at one end and not axially aligned with the stator 2 at the other end, as shown in Figures 8-9. Specifically, in the embodiment shown in FIG. 8,

The direction of the resulting compensating axial force F _ma ' is shown by the arrow in the figure from

side pointing

side; while in the embodiment shown in Figure 9,

At this time, the direction of the generated compensating axial force F _ma ' is shown by the arrow in the figure from

side pointing

side.

Additionally and/or alternatively, where appropriate, the relative position of the respective transverse center planes of the stator 2 and the rotor 3 may also be used to define the axial offset of the rotor 3 relative to the stator 2 .

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.

While some embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. The appended claims and their equivalents are intended to cover all modifications, substitutions and changes as fall within the scope and spirit of the invention.

Claims (10)

1. An electromagnetic arrangement comprising: a stator (2) and a rotor (3) rotatable relative to the stator (2), wherein the rotor (3) is located in a radial direction of the stator (2) inside or radially outside, and at least one of said stator (2) and said rotor (3) has a skewed structure, wherein said electromagnetic arrangement further comprises compensation means for at least part of The first axial force (F _ma ) acting on the rotor ( 3 ) by the magnetic field caused by the deflecting structure is compensated effectively. 2. The electromagnetic arrangement structure according to claim 1, characterized in that, The compensating means comprise: arranging the rotor (3) with an axial offset relative to the stator (2) so as to at least partially cancel the first shaft by the interaction of the stator magnetic field with the rotor magnetic field. The second axial force (F _ma ') towards the force (F _ma ). 3. The electromagnetic arrangement structure according to claim 2, wherein, The direction in which the rotor (3) is axially offset with respect to the stator (2) depends on the direction of the first axial force (F _ma ) such that the second axial force (F _ma ' produced) ) is opposite to the first axial force (F _ma ). 4. The electromagnetic arrangement according to any one of the preceding claims, characterized in that, The rotor (3) has an axial offset relative to the stator (2) in a direction co-directional with the first axial force ( _Fma ). 5. Electromagnetic arrangement according to any one of the preceding claims, characterized in that, The rotor (3) is arranged to extend axially beyond the stator (2) at one axial end and axially retract relative to the stator (2) at the other axial end. 6. Electromagnetic arrangement according to any one of the preceding claims, characterized in that, The compensation means includes: making the relative axial position of the rotor (3) and the stator (2) satisfy the following formula:

in,

represents the axial offset vector of the rotor (3) at its first axial end (10) relative to the stator (2),

represents the axial offset vector of said rotor (3) relative to said stator (2) at its second axial end (11) disposed opposite said first axial end (10),

A positive value means that the rotor (3) protrudes axially relative to the stator (2) at the corresponding axial end, while

A negative value means that the rotor (3) is axially retracted relative to the stator (2) at the corresponding axial end, in,

include

and

There are differences in sign and/or absolute magnitude. 7. 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 from

and

The direction in which the concerned axial side of the smaller one points to the concerned axial side of the larger one corresponds to the direction of said first axial force (F _ma ). 8. The electromagnetic arrangement structure according to claim 6 or 7, characterized in that the rotor (3) and the stator (2) are arranged in any one of the following ways: make

and

have opposite signs; make

and

have the same sign and different absolute values; make

and

Only one of them is zero. 9. The electromagnetic arrangement structure according to any one of claims 6-8, wherein, Used to define the axial offset vector

and

The axial ends (8, 9, 10, 11) are: the respective natural ends of the stator (2) and/or the rotor (3); or at least one of the respective stator (2) and/or rotor (3) influencing magnetic fields The axial end of the member. 10. An electric machine having an electromagnetic arrangement according to any one of the preceding claims and a rotating shaft (6) coupled in rotation with the rotor (3).

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