Patent Application
20250105687
The invention relates to a dynamoelectric rotary machine.
With reluctance machines and permanently excited machines, in particular with internal magnets, it is often necessary to make compromises between rotor strength or speed stability and magnetic leakage. The speed of the machine is often limited by low rotor strength or power density and/or torque density are reduced by magnetic leakage. In most cases, the achievement of a desired speed stability is at the expense of power density or torque density.
The invention is based on the object of improving a machine in this respect.
The object is achieved by claim 1, i.e., a dynamoelectric rotary machine having:
The stator field is advantageously generated by energizing the stator winding.
One embodiment is advantageous, according to which the first material is a soft magnetic material, for example, iron and/or cobalt.
Other materials, in particular materials with saturation induction of at least 2.1 T, are also possible.
The first material is used to guide the magnetic flux. The first material is advantageously arranged in the rotor in such a way that, on the one hand, it conducts the magnetic flux of the stator field in the d-axis flux direction of the rotor particularly well and, on the other hand, conducts the magnetic flux of the permanent magnets in the q-axis flux direction of the rotor particularly well.
One embodiment is advantageous, according to which the second material is a non-magnetic material, for example, non-magnetic steel, for example E316.
The second material represents high resistance for the magnetic flux.
The material is advantageously arranged in the rotor in such a way that it offers high resistance to the magnetic flux of the stator magnets in the q-axis flux direction of the rotor and reduces the magnetic leakage of the PM magnets in the rotor.
One embodiment is advantageous, according to which the rotor has a region surrounding an inner periphery of the rotor in which the second material is formed.
This enables good stability of the rotor to be achieved, in particular in a region adjacent to a shaft.
One embodiment is advantageous, according to which the rotor has a region adjacent to an outer periphery of the rotor in which the second material is formed.
This also has a positive effect on the speed stability of the rotor.
One embodiment is advantageous, according to which a region in which a third material is formed is arranged between the region surrounding the inner periphery and the region adjacent to the outer periphery.
One embodiment is advantageous, according to which the third material is a permanent magnetic material.
This embodiment is advantageous since the stator magnets can generate high reluctance torques and in addition high torques can be generated in conjunction with the permanent magnets.
This enables high torque density or power density to be achieved.
Preferably, the regions with the first material and the second material are produced by means of screen printing or stencil printing. This is achieved in particular by the method explained below. Preferably, cut-outs or recesses are provided in the rotor into which preferably prefabricated permanent magnets are inserted.
One embodiment is advantageous, according to which the third material is tangential to the region surrounding the inner periphery and the region adjacent to the outer periphery.
This arrangement is explained in more detail in the description of the figures.
The permanent magnets are securely fixed in this way. Preferably, they are additionally fixed with adhesive and/or resin.
One embodiment is advantageous, according to which the region in which a third material is formed is in the shape of a rectangle,
wherein the region surrounding the inner periphery has at least a portion shaped so as to be flush with a side of the tangential rectangular region.
One embodiment is advantageous, according to which the region adjacent to the outer periphery has at least a portion shaped so as to be flush with a side of the tangential rectangular region.
This means that prefabricated permanent magnets can be used and easily pushed or pressed into the rotor.
One embodiment is advantageous, according to which two further regions are formed adjacent to the outer periphery in which the second material is formed, wherein a further region is formed between the further regions and tangential thereto in which the third material is formed.
The third material is advantageously arranged in the q-axis flux path of the rotor. The third material is preferably present in the form of permanent magnets. On the one hand these generate their own magnetic field in the q-axis, on the other, they also generate magnetic resistance to the stator field in the q-axis,
The reluctance torques are particularly high if the soft magnetic anisotropy of the rotor is high. This is advantageously achieved if the magnetic resistance is low in the d-path (for example, few air gaps or little non-magnetic material) and if there is a lot of non-magnetic material in the q-path. The magnets then act advantageously like non-magnetic material due to the low permeability.
The magnets advantageously also form torques due to their magnetic flux. For this purpose, little non-magnetic material or a sufficiently large air gap is advantageously formed in the q-path (apart from the magnets).
One embodiment is advantageous, according to which the first material and the second material are connected with a material bond.
This makes it possible to create stable individual rotor layers and thus build a fixed-speed rotor.
One embodiment is advantageous, according to which the region surrounding the inner periphery has star-shaped extensions.
This further reduces the magnetic leakage flux in the inner rotor region and also increases the strength.
The object is furthermore achieved by a rotor for a dynamoelectric rotary machine having a plurality of material layers arranged one behind the other.
The object is furthermore achieved by a method for producing such a rotor, wherein a material layer comprises at least a first region having a first material and at least a second region having a second material, wherein the material layer furthermore comprises at least one cut-out, with the following steps:
The following describes and explains the invention in more detail with reference to exemplary embodiments depicted in the figures.
It is shown in:
The machine 1 has a stator 2 with a stator winding 11. In addition, the machine 1 has a rotor 3. The rotor 3 has an at least substantially cylindrical recess (see reference symbol 0 in
The first material 8 is formed in a region of the rotor 3 in which a q-axis flux path 51, 52 of a magnetic flux which can be brought about by a magnetic stator field that can be generated by the stator winding 11 is located. The magnetic stator field and hence the magnetic flux are generated by energizing the stator winding 11.
The second material 9 is formed in a region of the rotor 3 in which a q-axis flux path 51, 52 of the magnetic flux is located.
Advantageously, the first material 8 is a material that facilitates the guidance of a magnetic flux. The first material 8 contains, for example, iron and/or cobalt or an alloy of iron or iron-cobalt. A saturation induction of the material of at least 1.8 T, advantageously at least 2.1 T, is advantageous.
The first material 8 is advantageously arranged in the rotor 3 in such a way that, on the one hand, it conducts the magnetic flux of the stator field in the d-axis flux path 5 of the rotor 3 particularly well and, on the other hand, conducts the magnetic flux of a permanent magnet in the q-axis flux path 51, 52 of the rotor 3 particularly well.
Advantageously, the second material 9 is non-magnetic (in particular with a saturation induction of ≤0.1 T) and represents high resistance for the magnetic flux.
Advantageously, the second material 9 has non-magnetic steel, for example, E316.
The second material 9 is advantageously arranged in the rotor 3 in such a way that it offers high resistance to the magnetic flux of the stator field in the q-axis flux path of the rotor 3 and reduces the magnetic leakage of the permanent magnets in the rotor 3.
The figure shows an inner periphery and an outer periphery of the rotor 3. A region 20 surrounding the inner periphery of the rotor 3 advantageously has the second material 9. The material is advantageously non-magnetic.
In addition, the figure shows that there are multiple regions adjacent to the outer periphery 57, 58, 59 of the rotor 3 on the outer periphery 57, 58, 59 of the rotor 3, which advantageously contain the second material 9.
In addition, the figure shows a third material in the shape of a permanent magnet 54, 55 and 56. In the figure, the permanent magnet 54 is adjacent to the region 57 and the region 20. The permanent magnet 54 is tangential to the region 57 and the region 20. In the figure, the permanent magnet 54 is formed in the shape of a rectangle.
The regions 57 and 20 are advantageously formed, at least in portions, in such a way that they are in each case flush with a side of the tangential rectangular permanent magnet 54. This can also be identified in the rectangular permanent magnet 55. Two regions 58 and 59 adjacent to the outer periphery 57, 58, 59 are formed in portions in such a way that they are in each case flush with a side of the rectangular permanent magnet 55.
Alternatively, the region 20 can also have a further material 12 with particularly high-tensile strength (<=500 MPa). This allows high pressures to be applied to the shaft 6 and increases the maximum permissible speeds of the machine.
The magnets in the q-axis flux path of the rotor 3 advantageously generate their own magnetic field in the q-axis. On the other hand, they also generate magnetic resistance to the stator field in the q-axis.
The high magnetic resistance advantageously means that the stator magnetic field in the q-axis can only be formed to a small extent. This advantageously results in high torque-current linearity and hence in high torques that are formed by the permanent magnetic field and stator magnetic field.
The materials are advantageously connected to one another by a material bond, in particular by means of metal diffusion. The tensile strength of this connection is advantageously greater than 200 MPa at 200° C.
In addition, the rotor plate has a plurality of cut-outs. A cut-out for the shaft 6 is marked 0. In addition, cut-outs for permanent magnets are marked 540 and 550. The region surrounding the inner periphery of the rotor layer 7 can be formed as a ring or in an annular shape, as shown in the figure. The region 20 has the same material as the regions 58, 59 arranged on the outer periphery. However, a further material 12 in the region 20 is also conceivable in order to increase the tensile strength. This is, for example, high-alloy steel.
The regions 58, 59 and 57 arranged on the outer periphery also increase the strength of the rotor layer 7.
The figure shows a rotor layer 7 that can be produced by the method described in
Advantageously, a plurality of these rotor layers 7 are joined together and then a prefabricated permanent magnet is inserted into the cut-outs 550, 540.
A length ls of the star-shaped extension 120 (see
This can, for example, be a ferrite magnet, in particular a ceramic ferrite magnet. However, NdFeB or SmCo magnets are also conceivable.
The stator 2 in
Advantageously, the stator has a plurality of stator layers arranged one behind the other, which have soft magnetic material, preferably with a saturation induction of at least 2.1 T.
Preferably, a stator layer is at least 50 μm and at most 200 μm thick. Preferably, the stator layer is thinner than 150 μm. The stator layer can, for example, be produced by means of a screen-printing method or a stencil-printing method.
The rotor layer 7 can also, for example, be produced by means of a screen-printing method or a stencil-printing method. Preferably, a rotor layer is at least 50 μm and at most 200 μm thick. Preferably, the rotor layer is thinner than 150 μm.
The invention offers the advantage that, due to the non-magnetic material in the rotor, the magnetic leakage flux is very low.
The embodiment shown in
The machine 1 has a very high level of efficiency. It is possible to achieve or even exceed energy efficiency class IE5. The advantage over conventional asynchronous and synchronous reluctance motors is particularly clear in the case of smaller machines (in particular under 20 kW).
In particular, the use of ferrite magnets means that the machine 1 has less mass and is cheaper. Ferrites also have the advantage that they are cheaper than rare earth magnets and have a lower CO2 equivalent. In addition, their availability is higher.
A PM synchronous machine with ceramic ferrite magnets has particularly low losses because no eddy currents flow in the ceramic magnets. The significant reduction in the internal rotor leakage flux also reduces copper losses in the stator.
The rotor 3 depicted is robust and rigid. Hence, it has a long service life, low vibrations and low noise levels.
The machine 1, is, for example, suitable for highly efficient industrial motors, but also for electromobility.
The embodiment has radial magnets 38. The region 20a surrounding the inner periphery is also shaped differently than in the embodiments shown so far. In the figure, the region 20a is formed as an octagon with eight sides, wherein four sides have a first length and a further four sides have a second length, wherein the second length is shorter than the first length. Two sides of equal length are arranged opposite one another in the figure.
The rotor 3 shown in this embodiment is not completely round, but has circular segment portions that are, for example, filled with air L. Alternatively, a non-magnetic material can also be inserted in this region marked with L.
The rotor 3 has regions 37 arranged on the outer periphery 57, 58, 59 which have the second material 9.
The permanent magnets 42, 43 and 33 shown in the figure are more slimline than the magnets in
The above-described rotor 3 advantageously has a plurality of rotor layers 7 arranged one behind the other. The rotor layer 7 comprises a plurality of regions that have different materials, but at least a first material and a second material.
In method step S1, a first suspension having at least one binder and solid particles is applied through a first stencil to a base surface to obtain a first green body.
The first stencil forms the regions that have the first material.
A second stencil advantageously maps the regions that have the second material.
Accordingly, in method step S2, a second suspension having at least a binder and solid particles is applied through the second stencil to a base surface to obtain a second green body.
In an optional method step S3, the binder can be expelled from the first green body.
In an optional method step S4, the binder can be expelled from the second green body.
The binder is preferably expelled by means of debinding.
In method step S5, the two green bodies are joined together.
Alternatively or additionally, the binder can be expelled after the joining of the green bodies in method step S6.
Hence, different procedures can be followed: the respective binder from the first green body and/or the second (and/or further) green body can be expelled before the joining in method step S3 and method step S4 of the first green body and the second green body (and/or further ones) and/or after the joining (see method step S6).
In method step S7, a permanent material-bonded cohesion of the two green bodies and the solid particles is obtained by heating and/or compaction, in particular by means of sintering.
In method step S8, the rotor layers 7 are joined together.
In method step S9, permanent magnets are inserted into the cut-outs.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22154011.5 | Jan 2022 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/051048 | 1/18/2023 | WO |
