EP2792051A1

EP2792051A1 - Transversal flux machine with halbach arrays

Info

Publication number: EP2792051A1
Application number: EP12798253.6A
Authority: EP
Inventors: Jens Hamann; Markus KLÖPZIG; Dietmar Stoiber; Markus Wilke
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2011-12-12
Filing date: 2012-11-28
Publication date: 2014-10-22
Also published as: WO2013087412A1; EP2605367A1

Abstract

The aim of the invention is to improve the power density of transversal flux machines. Therefore, a transversal flux machine is provided with a first active part and a second active part (1) which, in order to move along a predefined movement direction (2) relative to the first active part, magnetically interacts with said first active part. The second active part (1) is equipped with a magnet device (6 to 10). The magnet device has a Halbach array. Therefore, flux collectors in the second active part can be dispensed with, and therefore the weight of the transversal flux machine falls.

Description

description

Transverse flux machine with Halbach arrays The present invention relates to a Transversalflussma ^¬ machine with a first active part and a second active part which is for movement along a predetermined direction of movement relative to the first active part with this in magnetic interaction, wherein the second active part is equipped with a magnetic device ,

Today's torque motors typically have a Leis ^¬ processing density of 1 kW / kg. In all technical sectors in which such motors are used, one is, however, also sought, among other things, this power density to verbes fibers ^¬. This would be particularly in the automotive industry, be ^¬ Sonder but also in the aircraft industry an advantage. Spe ^¬ essential in the aerospace industry are needed drive systems ei ^¬ ner power density of 8 kW / kg.

Today, electric drive systems are typically used only for model aircraft. By Geiger Engineering, for example, a high-pole engine as aircraft ^{electric ¬} motor without gear known. It has a magnet pole 42 and an output of 20 kW at a limit speed of 2500 rpm. For the initial phase of this engine has a Leis ^¬ processing density of 3.6 kW / kg.

Transverse flux motors as rotary or torque motors are characterized by a ring winding, and the magnetic flux is transverse (perpendicular) to the plane of rotation. In three-phase transversal flux motors, each phase usually has its own permanent excitation. However, transverse flux motors are also known in which the three phases are fed by only one permanent magnet system. Transverse flux motors have the ability to realize high pole pairs and thus have small pole pitches. Thus, the dead weight per pole is small and consequently results in a favorable power to weight ratio. Due to the ring winding in transverse flux motors, the winding heads are eliminated. From the document EP 1063754 A2 a transversal ^¬ flow machine is known with the circumference of the rotor of the Ma ^¬ machine arranged permanent magnets in a number corresponding to the number of poles of the machine and possibly arranged between the permanent magnet flux guide pieces of mag- netic conductive material, and with about the scope of the

Stators of the machine arranged Polelementen for receiving windings for increasing a magnetic flux and for conducting the magnetic flux. To reduce the magnetic losses, in particular the iron losses and caused by stray fields losses in the stator, and thus to increase the power output of the efficiency of the machine is provided that at least a portion of Polele ^¬ ments of the stator, preferably those parts in which the magnetic Flow deviates from the radial direction, is made of magnetically isotropic material, for example of Magneti ^¬ cal sintered material.

Furthermore, the document EP discloses AI ei ^¬ ne single or 1,005,136 multiphase transverse flux machine with gate at Ro arranged in the circumferential direction of the permanent magnet in a number corresponding to the number of poles of the machine with possibly arranged between the permanent magnet flux conductors, and with the stator in the circumferential direction successively arranged U-yokes. To increase the torque at the same time as simple and inexpensive Konstrukti ^¬ on is provided that the U-yokes and or the Perma ^¬ nentmagnete or any Flussleitstücke compared to a direction parallel to the axis of rotation of the machine advantageously offset by a pole pitch or odd multiple of the pole pitch are oriented. The object of the present invention is to further exaggerate the power density of a transverse flux machine to he ^¬. According to the invention this object is achieved by a Trans ^¬ salsalflussmaschine with

a first active part,

a second active part, which is in magnetic interaction with it for movement along a predetermined direction of movement relative to the first active part, wherein

- The second active part is equipped with a magnetic device is ^¬ tattet, and wherein

- The magnetic device has a Halbach array.

Advantageously, therefore, the transverse flux machine is equipped with a magnetic device having one or more Halbach arrays. Such Halbach arrays have a continuously changing magnetization direction or represent a special configuration of Permanentmag ^¬ netsegmenten whose magnetization direction is tilted against each other by a certain angle in the direction of the longitudinal axis of the array. As a result, the flux density on one side of the Halbach array is increased and attenuated on the opposite side. Thus can be dispensed flow ^¬ collector with high weight so that last ^¬ Lich the power density of the transverse flux increases.

In one embodiment, a plurality of Halbach arrays can be arranged spaced apart in the direction of movement on the second active part, wherein the Halbach arrays in the second active part cause a magnetic flux perpendicular to the direction of movement ^¬ . It can be provided that in the direction of movement only a magnetic return element is arranged angeord ^¬ net on every second of the Halbach arrays on the first active part. As a result, the weight of the transverse ^¬ flow machine can be further reduced. According to another embodiment, the second active part has two spaced Halbach arrays, which extend in the direction of movement parallel to each other and substantially over the total extent of the second active part, so that in the second active part, a magnetic flux is caused parallel to the direction of movement. In this case, the first active part in the direction of movement may alternately have I- and U-shaped return elements, wherein an electrical conductor passes through the U-shaped return elements. This allows the magnetic flux to be closed around the track.

In another embodiment, the first active part magnetic return elements, which are skewed relative to the direction of movement by a pole pitch. Due to the skew, the magnetic flux can take a very short path.

Preferably, in the transverse flux machine is a three-phase machine, wherein the second active part has perpendicular to the moving direction of a triangular cross-section, Halbach arrays are disposed on three lateral surfaces of the second Ak ^¬ tivteils and each Halbach array on one of the lateral surfaces to a respective Halbach array on another of the lateral surfaces is offset by 120 ° electrically.

Thus, the transversal flux machine can also be used for the usual three-phase three-phase current system.

The one or more Halbach arrays have along their respective longitudinal axis a plurality of segments, wherein the magnetic Ori ^¬ entierungen of two adjacent of the segments in the direction of the longitudinal axis are each preferably tilted by 45 °, 90 ° or another predetermined angle other than 0 ° to each other. Depending on the length of the Halbach arrays can feiung so the appropriate STAF-, ie, the tilt angle from segment to segment, Festge ^¬ be inserted. In an ideal Halbach array, the magnetization changes continuously, in particular sinusoidally. The transverse flux machine is preferably designed as mehrphasi ^¬ ger torque motor. But it can also be realized for example as a linear motor or as a generator. In a torque motor, the second active part with the Halbach arrays preferably represents the rotor. Thus, the rotor can be made very low mass. In the case of Linearmo ^¬ tors, it is also advantageous if the second active part is the moving part, in particular the secondary part. By a low-mass secondary part can in turn achieve a high dynamics of the engine.

Further, it is advantageous if the second active part is hollow and flows through a coolant. With the cooling in the interior of the second active part, a higher power density can be realized.

The present invention will now be explained in more detail with reference to the accompanying drawings, in which: 1 shows a part of a rotor of a three-phase transverse flux machine with Halbach array transverse to the supply direction BEWE ^¬;

2 shows a diagram of the unwound rotor of FIG. 1;

3 shows a three-dimensional view of a section of a

Transverse flux motor with a rotor of FIG 1;

4 shows a view of a rotor with Halbach arrays one

The transverse flux machine according to another exporting ^¬ approximate shape;

5 shows the unwound rotor of FIG 4;

6 shows a cross section through the transversal flux machine with the rotor of FIG. 4;

7 shows the ring structure of a transverse flux motor of FIG

6;

8 shows a three-dimensional view of a section of the

Transverse flux motor of FIG 7 and

9 shows a view of a rotor of a Transversalflussmo ^¬ sector with Halbach arrays according to a further Ausfüh ^¬ tion form. The embodiments described in more detail below represent preferred embodiments of the present invention. In general, the present invention relates to a multiphase transverse flux machine. The following examples rela ^¬ hen on three-phase Transversalflussmotoren but whose construction principle is also applicable to other transverse flux.

The basic structure of a transverse flux motor for three phases can be seen in FIG. This is a torque motor, which represents a closed ring. In its interior a rotor extends with beispiels- example triangular cross-section, as is 6 angedeu ^¬ tet in FIG. A section of such a rotor is also shown in FIG. The rotor is annular and has a triangular cross section here. In other words, the second active part of the transverse flux machine, ie the rotor 1, in the direction of movement 2 (indicated by a double arrow in FIG. 1, since the movement can take place in both directions) has in sections substantially the shape of a prism. Such a prism-shaped portion of the rotor 1 is shown in FIG. The rotor ring or the triangular prism has three side surfaces 3, 4 and 5. In the example of FIG. 1, magnetic Halbach arrays 6, 7, 8 are shown only on the side surface 3. On the lower side surface 5, the Halbach arrays 9, 10 are merely indicated. On the third side surface 4 they are not visible.

The Halbach arrays 6 to 10 are arranged on the rotor 1 perpendicular to the direction of movement 2. Ie. the longitudinal axis of each ^¬ Halbach array 6 to 10 extends transversely to the direction of movement ^¬ tung 2 is located between two Halbach arrays 6, 7, 8 are respectively a gap 14, 15 °.

Based on the Halbach array 6, the basic structure ei ^¬ nes such an array is briefly explained. The Halbach array 6 consists of several segments 11, 12, 13. The magnetization ^¬ direction of the first segment 11 has on its surface perpendicular to the outside. The segment can therefore be referred to as north pole N. In contrast, the magnetization direction of the segment 13 points perpendicularly into the surface, so that a south pole S results. Between the segments 11 and 13 there is a segment 12 whose magnetization direction runs along the longitudinal axis of the Halbach array 6. Its magnetization direction is thus tilted by 90 ° both with respect to the magnetization direction of segment 13 and that of segment 11. This results in the typical Halbach phenomenon that the magnetic field on one side (the outwardly facing prism side) is amplified and weakened on the opposite side (directed towards the interior of the prism).

In FIG 2, the rotor of FIG 1 is shown in unwound form. That is, the side surfaces 3, 4 and 5 are shown side by side. There are also the Halbach arrays 6, 7, 8 on the side 3 and the Halbach arrays 9, 10 on the walls ^¬ ren side surface 5 can be seen. The Halbach arrays of page 5 are compared to the Halbach arrays of page 3 offset by 120 ° elec ^¬ trically. The electrical phase offset is shown on the left in FIG. Thus, it can be seen immediately that the Halbach array 9 is offset from the Halbach array 6 by 120 ° elec ^¬ trically. The 120 ° results from the three-phase system. The Halbach arrays on the side 4 are also electrically offset by 120 ° ^relative to those on page 5. The same applies between the Halbach arrays of page 4 and page 3.

In the example of FIG. 2, a Halbach array in the direction of movement 2 has the width of 120 ° electrically. A gap 14, 15 has the width of 60 ° electrical. In principle, the width of the Halbach arrays and the gaps can be freely selected within certain limits. In sum, in the present configuration, 180 ° must electrically result, so that For example, a Halbach array width of 100 ° and a gap width of 80 ° could be chosen in principle.

The first active part, in this case the stator, has magnetic backs 16, 17, 18, which repeat themselves in the direction of movement 2 after 360 °. The conclusions 16, 17, 18 extend in the plan view of FIG 2 congruent with the underlying Halbach arrays and thus extend perpendicular to the direction of movement. 2

FIG. 3 shows a short section (two pole pitches) of a transverse flux motor with a rotor of FIG. 1 and FIG. 2. There also the triangular structure of the Ro ^¬ tors with the Halbach arrays 6, 7, 9 (and others not marked in more detail) can be seen. The arcuate conclusions 16, 17 and 18 are part of the first active portion of the Transver ^¬ salflussmaschine, in this case of the stator 40. Each of the rear ^¬ connections 16, 17, 18 extends to a respective conductor 19, 20, 21, the phases U, The conclusions 16 to 18 can be formed from a ferromagnetic powder material (eg SMC - Soft Magnetic Composite) or from electrical steel sheets. They also have a width of 120 ° electrically and are arranged around the Ro ^¬ tor without offset from each other. On average, therefore, there is a magnetic inference of the stator 2 over every second Halbach array of the rotor 1.

Another embodiment of a transverse flux machine according to the invention is shown in FIGS. 4 to 8. FIG. 4 once again shows a rotor 1 which, in principle, has the structure of the rotor of FIG. 1, but with two half-axis arrays 22, 23 running along the direction of movement 2. That is, the longitudinal axes of the Halbach arrays extend in the direction of movement 2, which also means that the individual magnetically differently oriented segments are arranged one behind the other in the direction of movement 2. The orientations of the individual segments of the Halbach arrays result from the designations N and S as well as from those shown in FIG. drew arrows. From the north poles N, the magnetic orientation points to the outside and the south poles S to the inside. Transverse to the direction of movement are a Nordpolsegment 24 of a Halbach array 23 and a Südpolsegment 25 of the other Halbach array 22 on the side surface 3 of the Ro ^¬ gate with a gap 25 located therebetween. The gap 25 extends like the Halbach arrays along the ge ^¬ entire rotor 1. In the direction of movement closes to the Nordpolsegment 24, a magnetic segment 27 whose magnetic orientation to the Nordpolsegment 24, and a Südpol ^¬ segment 28 and a magnet segment 35 whose magnetization directed away from the south pole segment, in the Halbach array 23 at. In the Halbach array 22 closes in the direction of movement of the Südpolsegment 25, a magnetic segment 29 whose magnetic orientation of the Südpolsegment 26 points away, and a Nordpolsegment 30 and a magnet segment 36 whose magnetization is directed to the Nordpolsegment towards. The ^¬ se Halbach structure is repeated for both Halbach arrays 22, 23 in the direction of movement. 2

In FIG 5, the rotor 1 is shown again in unwound form. Again, it can be seen that the Halbach arrays 22 and 23 continue virtually infinite. In an angular range of 360 ° electrically located on average two poles, namely a south pole S and a north pole N. The magnetic ^¬ tables 27, 29 with magnetic orientation parallel to the direction of movement 2 are symbolized in Figure 5 only with arrows. Perpendicular to the Halbach arrays are located alternately in the direction of movement U-cores 31 and I-cores 32 of the stator. Each of these cores provides an inference from one north pole to an opposite south pole in the other Halbach array. In FIG 5, these U-cores and I-cores are shown in dashed lines.

The course of the flow proceeds, for example, out of a north pole segment N into a U core 31 to a south pole segment S (flow in the radial direction), from there via a Halbach segment to an underlying in Figure 5 north pole segment N (flow in the circumferential direction) and from there via an I-core to a Südpolsegment S of the opposite Halbach array (flow in the radial direction) and from there back to the starting North Pole segment via an intervening Halbach segment (flow in the direction of movement). The flow is carried out via the respective electrical conductor in the U-cores and under the conductor between the rotor and conductor in the I-cores.

This flow guide 33 is from a different perspective

(Looking along the direction of movement 2) shown in FIG. In this case, the cross section through the transverse flux machine of FIG. 6 shows U cores 31 and I cores 32. In the case of the conductor 19, the magnetic flux runs around it through the U core 31 to the Halbach array 22 and through the U axis I-core 32 back from the Halbach array 22 to the Halbach array 23. A support structure of the Halbach arrays is not shown in FIG. Between the stator-side U and I cores and the rotor-side Halbach arrays is in each case an air gap. In principle, the I-cores can also be dispensed with. However, this increases the leakage flux

The entire ring structure of a transverse flux machine having such a construction is shown in FIG. In particular, the U cores 31 and the I cores 32 are identically distributed on the circumference. Over the I-cores 32 and under the U-cores 31 the conductor 19 runs.

FIG 8 is similar to FIG 3 a short portion of the ring of Figure 7 or a corresponding Transversalflussmo ^¬ tors. The Halbach arrays 22, 23 running in the direction of movement 2 here have a square cross-section. But they can also, for example triangular cross-section aufwei ^¬ sen so that the located at the tips of the triangle Halbach arrays can be arranged closer to each other. The Half-axis segments are shown here very briefly in the direction of movement. This is intended to symbolize that at successive fol ^¬ constricting segments Halbach the magnetic orientation can be tilted not only about 90 °, but also with another angle, for example, 45 ° etc.

With this arrangement will become apparent with respect to the embodiment of FIG 3, the additional advantages that a clotting ^¬ Ger ßerdem leakage flux because of the closed flux guide and au- a better utilization of the total magnetic

Flow of existing permanent magnets is given. In addition, the edge length of the rotor section triangle can be arbitrarily ^¬ be elected and does not affect the interpretation of the Halbach array. Furthermore, high pole pair numbers can be performed.

FIG. 9 shows a further exemplary embodiment of a rotor of a transverse flux motor according to the invention. Here is on each side 3, 4, 5 of the rotor with triangular cross-section each only a single Halbach array 34 neces ^¬ dig. The Halbach array 34 also extends in BEWE ^¬ supply device 2. The Halbach arrays are not offset on the three sides ^¬ surfaces 3, 4 and 5 to each other. Therefore, stator yokes (not shown in FIG. 9) are provided here, which are skewed. That is, a conclusion must, for example ^¬ from the North Pole segment N, on top of the side surface 3, to the Südpolsegment S, below on the side surface 4, dur ^¬ fen. The pole pitch τ corresponds to the distance between the

North pole segment N and the South pole segment S, relative to the center thereof.

In the three-phase transversal flux motors, each phase has its own permanent excitation. The excitation occurs here by Halbach arrays, which are located on the three sides of the rotor with a triangular cross-section. Because of Hal ^¬ bach magnets of iron-core flux collector that is necessary is not applicable if the transverse flux only Per ^¬ manentmagnete bipolar arrangement in the second active part or used in the rotor or rotor. The rotor or rotor can therefore be formed by a (ring-shaped) non-magnetically conductive core (eg A-magnetic steel or aluminum). The core can also be hollow to lead ^{¬ off} the rotor heat with a coolant or with a heat pipe.

In the present examples, a pole pair is always shown with a north pole and a south pole and a magnetic segment therebetween whose magnetic orientation is tilted by 90 °. At the end of a pole pair such a Mag ^¬ netsegment is also added. However, a pole pair can also be implemented, for example, from five subsegments. The additional magnet segments then have a magnetization direction, for example, 45 °, and are respectively Zvi ^¬ rule the poles and the magnetized magnet pieces orthogonally inserted. However, the segmentation of the Halbach arrays can also be further refined, wherein the tilt angle of the magnetization direction is then further reduced from segment to segment.

When realizing a transversal flux machine for three phases with rotor, which has a triangular cross-section, the triangles can be flattened at their acute corners. Thus, the internal "triangle" (rotor) can be attached to a rotation bracket and connected to the rotor hub.

In the embodiments described above, the rotors have a triangular cross-section. However, they can in principle also have a different cross-section, for example a horseshoe-shaped, a square or another polygonal cross-section. In particular, the rotor may also be hexagonal, the feed being done over 2 x 3 phases to compensate for the pulsating attractive forces (sin ² forces). For the stators, a support structure can be constructed, in which the individual conclusions are accurately inserted and the toroidal coils are hung. The encapsulation or impregnation of the ring winding can then take place in this support structure. Possibly. It is also possible to insert stiffeners made of fiber composite materials.

As shown above can thus be a three-phase transverse flux motor with staggered Halbach arrays on the sides of a rotor with a triangular cross-section realisie ^¬ reindeer, which connect all three phases with the excitation flux.

In addition, the stator ring lines (waveguide) can be provided with liquid cooling (eg water or oil). Thus, current densities of 80 to 100 A / mm ^{2 are} possible. Today, a maximum of 10 A / mm ^{2 can be} achieved.

Furthermore, the air gap induction between rotor and stator can be set across the thickness of the permanent magnets or Halbach arrays. In this case, a very high utilization can be achieved because the Luftspaltinduktionsniveau can be set by 50% higher ^¬ and the current density due to the short loop by a factor of ten. The design of the air gap induction and the multi-phase arrangement can be used to optimize noise generation and torque ripple. However, the biggest advantage of OF INVENTION ^¬ to the invention transverse flux machine is that flux collector in the rotor or rotor and thus their overall weight can be saved. In addition, the stator yokes need not necessarily be skewed so that they can be made easier.

Claims

claims

1. Transverse flux machine with

a first active part (40),

- a second active portion (1), which is for movement along ei ^¬ ner predetermined direction of movement (2) relative to the first active part with this in magnetic interaction, wherein

the second active part (1) is equipped with a magnetic device,

d a d u r c h e c e n c i n e s that

- The magnetic device has a Halbach array (6 to 10, 22, 23, 34, 35, 36).

2. Transversal flux machine according to claim 1, wherein a plurality

Halbach arrays (6 to 10, 22,23,34) spaced apart in the direction of movement at the second active part (1) are arranged and the Halbach arrays in the second active part a magnetic flux perpendicular to the direction of movement (2) call.

3. Transverse flux machine according to claim 2, wherein in the ^¬ direction of travel ^¬ (2) only over each second of the Halbach arrays (6 to 10, 22, 23, 34) on the first active part, a magnetic return element (16,17,18) is arranged.

4. Transverse flux machine according to claim 1, wherein the second active part (1) has two spaced Halbach arrays (6 to 10, 22, 23, 34), in the direction of movement (2) parallel to each other substantially over the total extent of the second active part extend, so that in the second active part, a magnetic flux is caused parallel to the direction of movement.

5. Transversalflussmaschine according to claim 4, wherein the first active part in the direction of movement alternately I- and U-shaped return elements (31,32) has, and wherein an electrical shear conductor (19,20,21) passes through the U-shaped return elements.

6. Transverse flux machine according to claim 1, wherein the first active part (40) has magnetic return elements, which are skewed relative to the direction of movement by a pole pitch.

7. The transverse flux machine according to any one of the preceding arrival sayings that is three-phase, the second active part (1) perpendicular ^¬ right direction of movement (2) has a triangular cross-section, Halbach arrays (6 to 10, 22,23,34) are arranged on three mantle ^¬ surfaces (3,4,5) of the second active part and each Halbach array on one of the lateral surfaces to a respective Halbach array on another of the lateral surfaces by 120 ° is electrically offset.

8. The transverse flux machine according to any one of the preceding claims, wherein each Halbach array (6 to 10, 22,23,34) sev- eral segments (11,12,13,24,25,28,30) along its Längsach ^¬ se comprises , and wherein the magnetic orientations of two adjacent ones of the segments in the direction of the longitudinal axis are each tilted by 45 °, 90 ° or another predetermined angle other than 0 ° to each other.

9. Transverse flux machine according to one of the preceding claims, which is designed as a multi-phase torque motor.

10. Transverse flux machine according to one of claims 7 to 9, wherein the second active part (1) is hollow and flows through a coolant.