WO2013014151A2

WO2013014151A2 - Electric machine

Info

Publication number: WO2013014151A2
Application number: PCT/EP2012/064495
Authority: WO
Inventors: Markus KLÖPZIG; Jens Hamann; Olaf KÖRNER
Original assignee: Siemens Aktiengesellschaft
Priority date: 2011-07-28
Filing date: 2012-07-24
Publication date: 2013-01-31
Also published as: WO2013014151A3; DE102011080008A1

Abstract

The invention relates to an electrical machine comprising a rotor and a stator, said rotor comprising permanent magnets and the stator comprising a coil and a stator pole which comprises stator surfaces which face the permanent magnets of the rotor, characterized in that at least one stator surface comprises a groove which is transverse to the movement direction of the rotor.

Description

description

Electric machine The invention relates to an electrical machine having a rotor and a stator in the form of a transverse flux machine. The number of individual stators, referred to below as the stator, corresponds to the number of phases of the electric machine in the case of trans-flux machines. Transverse flux machines are known from DE 37 05 089 AI and DE 10 2006 022 836 AI. It is found that the torque density for Transversalflussma ^¬ machines compared to conventional radial flux machines can reach much higher values. This transversal ^¬ flow machines for direct drives are advantageous to apply. Furthermore, it is found that with transversal flux machines a higher number of pole pairs can be performed than with radial flux machines. On the other hand, studies have shown that the torque ripple (pendulum moments and cogging torques) is relatively high in transverse flux machines. With the torque ripple and stronger oscillations of the radial ^¬ forces are connected. In addition, transverse flux machines typically have a higher noise level.

The object of the invention is to provide an electric machine with a rotor and a stator, which has a lower torque ripple.

The object of the invention is achieved by the electric machine according to claim 1. The reduction of the torque mentwelligkeit is achieved in that a groove is provided at least in egg ^¬ nem stator pole at least that is arranged transversely to the direction of movement of the rotor. Due to the groove, the torque ripple is reduced. In a further embodiment, the groove is arranged substantially perpendicular to the direction of movement of the rotor. Due to the vertical arrangement, a special reduction of the torque ripple is achieved. In a further embodiment, the groove extends over the entire length of the stator, which faces the permanent magnet. In this way, the entire effective length of the stator pole is used for arranging the groove.

In a further embodiment, adjacent stator poles have a fixed distance from one another in the direction of movement of the rotor, wherein the groove has the defined distance as the width. In this way, compensation for the distances of the stator poles is achieved by means of the groove.

In a further embodiment, the groove has a depth which substantially corresponds to a width of the groove in the direction of movement. Experiments have shown that this dimensioning causes a particularly efficient reduction of torque ripple.

In a further embodiment, the groove in the cross section of the direction of movement of the rotor seen two gegenü ^¬ berliegende parallel side surfaces which merge into a bottom ^¬ surface, wherein the bottom surface of the groove is disposed parallel to a front surface of the stator, which by the ^¬ manentmagneten of the rotor faces, and in which the groove is arranged.

In another embodiment, the groove has a U-shape in cross-section with rounded transitions between the side walls and the bottom surface.

In a further embodiment, a stator pole has two parallel grooves. In a further embodiment, the stator pole has three parallel grooves.

In another embodiment of the stator is in the form of a sheet metal packet, using different ^¬ Lich large sheets, the groove is realized. In a further embodiment, the stator pole is made of a soft magnetic composite material. As weichmag ^¬ genetic composites, for example, plastics verwen ^¬ det, with magnetic fillers such. As iron particles, nickel powder, nickel tin powder or Metglas (amorphous FeCoB alloy) are provided.

In a further embodiment, the permanent magnets are arranged obliquely to the direction of movement of the rotor. This he ^¬ goes further reducing the torque ripple.

In a further embodiment, two rows of permanent magnets are arranged side by side in the direction of movement, wherein the permanent magnets of the two rows are arranged offset in the direction of ^¬ movement of the rotor against each other. Also, a reduction of the Drehmomentwel ^¬ ligkeit is achieved.

In a further embodiment, the permanent magnets are arranged in the direction of movement of the rotor in such a way that the magnetic field direction in the plane perpendicular to the plane of rotation of the rotor from permanent magnet to permanent magnet changes direction by 90 °. Also by the wavy ^¬ ness of the torque is reduced.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments which will be described in connection with the drawings

FIG. 1 shows a schematic cross section through an electrical machine,

FIG. 2 shows a detail of a stator, FIG. 3 shows a schematic partial representation of a first embodiment of a machine,

4 shows a plan view of the arrangement of the permanent ^{magne ¬} te of the first embodiment of the machine of Figure 3, Figure 5 is a schematic partial view of a second embodiment of a machine,

Figure 6 is a schematic plan view of a further Anord ^¬ voltage of the permanent magnets of the rotor of Figure 5,

FIG. 7 shows a further embodiment of an arrangement of the permanent magnets of a rotor,

FIG. 8 shows a schematic plan view of the arrangement of FIG. 7,

FIG. 9 shows a schematic partial representation of a further embodiment of an electrical machine,

Figure 10 is a schematic plan view of the permanent ^{Magne ¬} te the arrangement of Figure 9, and

Figure 11 shows another embodiment of a stator.

FIG. 1 shows a schematic representation of a cross section through an electrical machine 1 in the form of a

Transverse flux machine with an internal rotor 2, which is rotatably mounted about a rotation axis 3. The rotor 2 is surrounded by an outer annular stator 4 with a coil in the form of a concentric stator coil 5, which is formed for example as a single-phase annular stator coil. Depending on the chosen embodiment, other types of coils may be used.

The rotor 2 has on its radial outer side Permanentmag ^¬ Nete 6, which have different poling directions and are distributed radially around the circular rotor 2 rotor. The stator 4 has stator poles on an inner side facing the permanent magnet 6. The stator 4 represents a single stator with transverse flux guidance. FIG. 1 shows a transverse flux machine with a stator 4 with a stator phase. Depending on the selected embodiment, a plurality of stator phases may also be provided. For example, a plurality of stators 4 and associated rotors 2 may be provided.

Figure 2 shows a schematic partial view of a view of the inside of the stator 4 with two stator poles 7, 8. The stator poles 7, 8 are arranged side by side and in a plane. The stator poles 7, 8 are connected via stator yokes 9, 10 with a stator ring 11. The stator ring 11 is annular and surrounds the rotor 2, wherein the stator poles 7, 8 are aligned in the radial direction on the axis of rotation 3 in the direction of the permanent magnets 6 of the rotor 2. The stator poles 7, 8 have stator surfaces 12, 13, which face the permanent magnet 6 and are preferably arranged parallel to a lateral surface of the rotor 2, which is formed by the permanent magnets 6. In the stator surfaces 12, 13 grooves 14, 15 are arranged. The illustrated stator poles 7, 8 are in the form of so-called claw poles, which have conically tapering stator surfaces 12, 13. Depending on the selected embodiment, the stator poles 7, 8 may also have identical rectangular Sta ^¬ torflächen 12, 13. The invention is not limited to the described embodiment of the claw-pole ^machine . The invention can also be applied to other types of trans-flow machines. In contrast to the radial flux machine, the number of rotor poles in transconductive machines can be identical to the number of pole shoes in the stator.

Figure 3 shows a partial schematic view of a partial ^¬ cross section in the plane perpendicular to the rotational axis 3. Here, alternately, a first and a second stator pole 7, 8 with a first and a second stator 12, 13 Darge ^¬ represents. The stator surfaces 12, 13 are associated with the permanent magnet 6. In the selected representation, the circular path of the outer surfaces of the permanent magnets 6 is simplified Representation shown as a flat line. Adjacent Perma ^¬ nentmagnete 6 have on the radially outer surface differ on ^¬ Liche poles whose orientation is shown in the form of arrows. In addition, the permanent magnets 6 are fixed on the radial inside of an iron yoke 16, which is annular. The stator poles 7, 8 are each spaced by ei ^¬ nen distance 17. In addition, the stator poles 7, 8 are formed narrower in the region of the stator surfaces 11, 12 than the permanent magnets 6.

The stator surfaces 12, 13 each have at least one groove 14, 15. The grooves 14, 15 may have different widths and / or different depths. The width is seen in the direction of movement of the rotor 2. Good effects for reducing the torque ripple were by grooves

14, 15, which are approximately as wide as the distances 17, which are the stator poles 7, 8 spaced in the direction of movement of the rotor. Depending on the selected embodiment, grooves 14, 15 may also be narrower or wider. In addition, good values for the Reduzie ^¬ tion of torque ripple have thus shown that the grooves 14, 15 are nearly as deep as it is wide. Depending on the selected ge ^¬ embodiment, the grooves in cross-section may have perpendicular to the rotational axis of the rotor have an angular or claimed from end to U-shape.

Figure 4 shows a plan view of the outside of the Perma ^¬ nentmagnete 6 of the rotor 3, where boundaries are located between the permanent magnets 6 eighteenth The direction of movement is indicated by an arrow 24. In addition, projected areas 19 of the distances 17 are shown as a simple hatching. Furthermore, second surfaces 20 are drawn as a cross hatch corresponding to the projected area of the first and second grooves 14, 15. As can be seen from FIG. 4, the areas of the projected area 19 of the spacings 17 and the projected second area 20 of the grooves 14, 15 are the same size. In the arrangement of Figure 3, the magnets are arranged parallel to the axis of rotation 3. The permanent magnets 6 of the rotor 2 are preferably designed in such a way that they cancel the sum of the tangential forces in the rotor. This applies to the reluctance forces that act between seeing the permanent magnet of a phase and the iron core of a phase. Due to the permanent magnet arrangement, a sinusoidal magnetic flux is generated.

FIG. 5 shows a further arrangement of permanent magnets 6 of the rotor 2, which, contrary to the embodiment of FIGS. 3 and 4, are not arranged perpendicular to the direction of movement 24 but are inclined at an angle thereto.

FIG. 6 shows the plan view of the permanent magnets of FIG. 5. The boundaries 18 between the adjacent permanent magnets 6 are shown in FIG. In addition, the proji ^¬ ed first face 19 are shown of the distances 17 and the projected second surfaces 20 of the grooves 14, 15 °. Due to the oblique arrangement of the permanent magnets 6, a further reduction of the torque ripple can be achieved.

Figure 7 shows a further arrangement of permanent magnets 6, wherein in this embodiment, two rows of permanent magnets are arranged side by side. The first and second series 21, 22 each have contiguous permanent magnets 6 on ^¬ with different polarizations. In addition, the boundaries 18 between the adjacent permanent magnets 6 are located. Along the direction of rotation 24, the magnetic polarity of the adjacent permanent magnets 6 changes.

FIG. 8 shows the top view of the permanent magnets 6 of FIG. 7. As can be seen from FIG. 8, the boundaries 18 between the permanent magnets 6 of the two rows 21, 22 of permanent magnets are shifted from one another. This also achieves a reduction in torque ripple.

FIG. 9 shows a further embodiment of a machine 1, in which the rotor 2 is a Halbachsystem as Permanentmagnetan- Has order. In a simple embodiment of the Halbachsystems adjacent permanent magnets 6 each have a magnetic pole, which changes from permanent magnet to permanent magnet in each case by 90 ° clockwise or counterclockwise. In this ^{embodiment, the} permanent magnets 6 are arranged on a nonmagnetic yoke 23. The magnetization direction is shown in the form of arrows. Depending on the selected embodiment, one or two rows 21, 22 of the permanent magnets 6 arranged in the Halbach arrangement can be provided.

FIG. 10 shows an arrangement with two rows 21, 22 of permanent magnets according to the half-axis system of FIG. 9. A further reduction of the torque ripple can also be achieved by this arrangement.

The permanent magnets 6 preferably have the same width in the direction of movement 24 of the rotor 2, as shown in Figure 9. In the exemplary embodiment illustrated, the polarity of the permanent magnets changes counterclockwise by 90 ° in each case.

FIG. 10 shows a first and a second row 21, 22 of permanent magnets, which are arranged in the Halbach system according to FIG. In the case of the two rows 21, 22, the boundaries of 18 adjacent permanent magnets of a row 21, 22 are offset laterally relative to the boundaries of adjacent permanent magnets. FIG. 10 shows the projected first surfaces 19 of the spacings 17 and the projected second surfaces 20 of the grooves 14, 15.

Depending on the selected embodiment can be ^¬ into a stator of the stator pole, two or more grooves. The grooves are preferably aligned parallel to one another and parallel to the axis of rotation 3. In the arrangement of more than two grooves, the width of the grooves of a stator surface may be selected in such a way that the sum the width of the grooves in the direction of movement 24 corresponds to the width of a distance 17.

FIG. 11 shows, in a schematic representation, a further embodiment of a stator 4 which has two stator poles 7, 8 whose stator faces 12, 13 are rectangular in shape. In addition, two grooves 14, 15 are respectively formed on the stator surfaces 12, 13. Depending on the selected embodiment, more than two grooves 14, 15 may be arranged in a stator surface 12, 13 of a stator pole 7, 8. The stator surfaces 12, 13 are arranged parallel to the axis of rotation of the rotor.

Depending on the selected embodiment, the stator poles 7, 8 may be layered in the form of sheet metal pakets. In this case, the sheets of the laminated core may be dimensioned in such a way that the width of a groove 14, 15 corresponds to a single or multiple thickness of a sheet and the grooves are realized by differently shaped sheets.

In a further embodiment, a stator of a machine 1 may be realized in the form of a soft magnetic composite. Although the invention in detail by the preferred embodiment has been illustrated and described in detail, the invention is not limited by the disclosed examples is ^¬ limited and other variations can be derived therefrom by the skilled artisan without departing from the scope of the invention.

Instead of the described embodiment, training of the stator in the form of a claw pole, other shapes of the stator and other forms of rotor, and in particular, other arrangements of the permanent magnets used ^¬ the. Furthermore, instead of an internal rotor, it is also possible to use an electric machine with an external rotor and an internal stator. be. In addition, the invention can also be used in linear motors in an analogous manner. Depending on the selected embodiment, the electrical machine may be designed as Elect ^¬ romotor or a generator.

The invention relates to an electrical machine having a rotor and a stator, wherein the rotor has permanent magnets ^¬, said stator having a coil and stator poles, said stator poles are arranged the permanent magnet of the rotor conces-, wherein at least one stator pole has a groove ^¬ points, which is arranged transversely to the direction of movement of the rotor.

Although the invention in detail by the preferred embodiment has been illustrated and described in detail, the invention is not limited by the disclosed examples is ^¬ limited and other variations can be derived therefrom by the skilled artisan without departing from the scope of the invention

Claims

claims

1. Electrical machine (1) with at least one rotor (2) and with at least one stator (4) having at least one stator phase, the rotor (2) having permanent magnets (6), wherein the stator (4) is a coil ( 5) and stator poles (7, 8), the stator poles (7, 8) having stator surfaces (12, 13) which face the permanent magnet (6) of the rotor, characterized in that at least one stator surface (12, 13) has a groove (14, 15) which is arranged transversely to the movement direction ^¬ (24) of the rotor (2).

2. Machine according to claim 1, characterized in that the groove (14, 15) is arranged substantially perpendicular to the direction of movement (24) of the rotor (2).

3. Machine according to one of claims 1 or 2, characterized in that the groove (14, 15) over the entire length of the stator (12, 13) of the stator (7, 8) extends.

4. Machine according to one of claims 1 to 3, characterized in that adjacent stator poles (7, 8) in the movement direction ^¬ a fixed distance (17) from each other, and that the groove (14, 15) has a width, the is within the range of the specified distance.

5. Machine according to one of claims 1 to 4, characterized in that the groove (14, 15) has a depth which substantially corresponds to a width of the groove in the direction of movement (24).

6. Machine according to one of claims 1 to 5, characterized in that the groove is formed in cross section in the direction of movement of the rotor U-shaped.

7. Machine according to one of claims 1 to 6, characterized in that the permanent magnets (6) are arranged obliquely to the movement ^¬ direction (24) of the rotor (2).

8. Machine according to one of claims 1 to 6, characterized marked ^¬ characterized in that at least two rows (21, 22) of permanent ^¬ magnets (6) are arranged side by side in the direction of movement of the rotor (2), wherein the permanent magnets (6) of the two rows (21, 22) are offset in the direction of movement (24) against each other.

9. Machine according to one of claims 1 to 8, characterized in that in the direction of movement (24) on the rotor (2) a row (21, 22) of permanent magnets (6) is arranged, that adjacent permanent magnets (6) have different magnetic Polungsrichtungen, wherein the poling ^¬ directions of the permanent magnet are alternately poled in the direction of the stator and in the direction away from the stator.

10. Machine according to one of claims 1 to 9, characterized ge ^¬ indicates that the stator pole (7, 8), two or more pa ^¬ rallele grooves (14, 15).

11. Machine according to one of claims 1 to 10, character- ized in that the stator pole (7, 8) in the form of a sheet ^¬ packet of layers is formed, wherein the groove is realized by differently shaped layers.

12. Machine according to one of claims 1 to 8, character- ized in that the stator pole (7, 8) is made of a soft magne ^¬ tables composite material.