DE102022116463A1 - Superconducting bearing arrangement - Google Patents

Abstract

The present invention relates to the technical field of physics and superconductivity and relates to a superconducting bearing arrangement. The object is to provide a superconducting bearing arrangement which has a simple and inexpensive structure, enables improved cooling while simultaneously reducing thermal losses and a improved and more flexible levitation behavior of the superconducting bearing is made possible. This is achieved by a superconducting bearing arrangement which has at least one cryostat, in which at least one short-circuited static coil made of a superconducting strip material is arranged with a superconducting conductor loop extending from the static coil The proposed superconducting bearing arrangement can be used, for example, in drive technology in vehicles and aircraft as well as in wind generators.

Description

The present invention relates to the technical field of physics and superconductivity and relates to a novel superconducting bearing arrangement, such as can be used, for example, in drive technology in vehicles and aircraft as well as in wind generators.

In mechanical bearings, friction and the associated wear and heat generation are the main causes of energy losses and bearing defects. In contrast, superconducting magnetic bearings, thanks to their non-contact design, enable friction-free operation, which is significantly more energy efficient compared to other bearing systems. The use of superconducting bearings makes it possible to make storage more energy efficient and therefore more economical in a variety of applications.

The characteristic feature of a superconducting bearing is that it can absorb forces in all spatial directions under defined conditions, which means that in a rotating superconducting bearing, both axial and radial forces in the tensile and compressive directions are stable.

Fully superconducting bearings can be used to increase the levitation force density. These have so far been operated with convective helium gas cooling. Such helium gas cooling requires two nested vacuum chambers, an outer chamber for thermal insulation and a second chamber inserted into the outer chamber in which the bearing with the helium atmosphere is placed. Known fully superconducting bearings also connect superconducting coils with expensive solid superconductor disks.

Various solutions in connection with superconducting bearings are known from the prior art.

From the DE 10 2009 049 889 A1 a method for assembling a superconducting bearing is known, wherein the bearing comprises a first bearing ring with a first body made of a type 2 superconducting material and a second bearing ring with a second body made of a type 2 superconducting material. The method includes mounting the two bearing rings and simultaneously impressing an external magnetic field that penetrates both corpora into the first body and the second body.

From the DE 10 2010 004 904 A1 a permanent magnetic bearing for supporting a shaft on a housing is known, the bearing having a first permanent magnet attached to the shaft, a second permanent magnet attached to the housing, and an auxiliary bearing with a superconductor located in a magnetic field made of a type 2 superconducting material includes.

Furthermore, from the DE 10 2017 212 675 A1 a storage device with a first storage component and a second storage component is known, wherein the second storage component is preferably mounted in a floating manner relative to the first storage component by means of a first storage device and a second storage device which differs in storage type from the first storage device and the storage type of the first storage device and the second storage device one each consists of a magnetic bearing, a superconductor bearing and a fluidic bearing.

From the DE 10 20182217 983 A1 a rotor for an electrical machine with a central rotor axis is known, comprising a rotor carrier and at least one permanent magnetic superconducting magnet device which is mechanically supported by the rotor carrier and has one or more superconducting magnetic elements, the respective superconducting magnetic element being embedded in a suitable, assigned radially outer recess of the rotor carrier is. The respective superconducting magnetic element is formed by at least one strip conductor stack made up of several superconducting strip conductors and the respective strip conductor stack is fixed in the associated recess by a pole cap arranged radially further out, the pole cap holding the individual strip conductors together in the strip conductor stack.

The disadvantage of the solutions known from the prior art is that due to the cooling required for superconducting bearings, the bearing arrangement is complex and high thermal losses arise due to the various components of the bearing arrangement and their connections. Another disadvantage is that known superconducting bearings are limited in their achievable levitation force per bearing surface due to the use of permanent magnets and are cost-intensive due to the material of the permanent magnets.

The object of the present invention is to provide a new superconducting bearing arrangement with which the aforementioned disadvantages of the prior art are eliminated.

The task is solved with the technical features of the main claim. Advantageous refinements are the subject of the subclaims, with the invention also combining the individual subclaims in the sense of an and combination function as long as they are not mutually exclusive.

The object is achieved according to the invention with a superconducting bearing arrangement which has at least one cryostat, in which at least one body made of a superconducting strip material and short-circuited with a conductor loop extending from the static coil, at least one body having superconducting strip material and which can be stored in a floating manner, at least a radiation-emitting cooling device with a connected cooling element, at least one coupling element and at least one electrical generator arranged outside the cryostat are present, the floating body being connected to the coupling element and being at least partially arranged in the coil core and in the area of the end face of the static coil, and the static coil can be energized in a contactless manner by the electrical generator via the conductor loop.

Advantageously, a structural element is arranged between the coupling element and the floating body, which is surrounded by a similarly designed cooling structure.

It is also advantageous if the structural element and the cooling structure are designed to meander.

It is also advantageous if at least the floating body is formed from segments of the superconducting strip material.

And also advantageously, the cooling element is a cold head component.

In an advantageous embodiment of the superconducting bearing arrangement, the superconducting strip material of the floating body at least partially has a first surface coating and the superconducting strip material of the static coil and / or the cooling element at least partially has a second surface coating, the emissivities of which are different, it being particularly advantageous if the emissivity of the first surface coating is greater than the emissivity of the second surface coating.

The electrical generator advantageously has a Halbach magnet arrangement.

The coupling element is also advantageously made from a fiber-reinforced composite material.

And furthermore, at least one thermal insulation element is advantageously arranged between the floating body and the cooling device.

According to the invention, a superconducting bearing arrangement is provided which has a simple and cost-effective structure, enables improved cooling while reducing thermal losses and enables improved and more flexible levitation behavior of the superconducting bearing.

This is achieved by a superconducting bearing arrangement which has at least one cryostat, in which at least one short-circuited static coil made of a superconducting strip material is arranged with a superconducting conductor loop extending from the static coil.

The proposed static coil, which is made of a superconducting strip material and short-circuited, is understood as an active system for generating magnetic fields, while, in contrast, passive systems use permanent magnets for generating magnetic fields.

To produce the static coil, a superconducting strip material is used that is partially cut lengthways in the middle, with the ends of the strip material remaining intact, so that a conductor loop is created. To produce the static coil, the superconducting strip material is wound onto several coil cores and an additional conductor loop is formed from the superconducting strip material of the static coil, which extends to the wall of the cryostat.

Replacing superconducting solid materials known from the prior art with superconducting strip material in a superconducting bearing arrangement has the advantage that, with a good magnetic effect, the manufacturing costs of the entire system are significantly reduced. In addition, superconducting strip materials enable greater flexibility in bearing design and significantly higher levitation force densities.

It was found that with a static coil made of superconducting strip material, significantly higher magnetic fields are generated than can be achieved, for example, with the use of permanent magnets. With the proposed static coil, which is made of a superconducting material, the levitation force can be significantly increased both via the active bearing surface and through the generated magnetic flux density, thereby providing significantly higher magnetic fields in the coil core be provided. The levitation forces increase as the square of the coil current.

Another advantage is that the ohmic losses are reduced, since the coil is seamless and therefore has no solder joints due to the strip material designed as a conductor loop.

Rare earth barium copper oxide (RebCo) has proven to be a particularly advantageous material for the superconducting strip material. ReBCO superconductors have the property of withstanding particularly strong magnetic fields and, due to their stronger magnetic field and their relatively high superconducting critical temperature, can be available for very compact and cost-effective use.

According to the invention, the superconducting bearing arrangement has at least one cooling device with a connected cooling element. The cooling element can advantageously be a cold head component arranged in the cryostat and integrated into the arrangement in such a way that it is connected to at least one coupling element and/or to the cooling structure in order to remove heat from the entire system and at least to the floating body and the static coil to set the required critical transition temperature of the superconducting strip material.

To avoid convective helium gas cooling, it is proposed that the floating body be set below its critical transition temperature during operation using radiation cooling. For this purpose, it can advantageously be provided that the floating body made of a superconducting strip material has a first surface coating which has a high emissivity. In contrast, it can advantageously be provided that the static coil and/or the cooling element has a second surface coating which has a lower emissivity compared to the first surface coating of the floating body. This ensures that the highest possible heat radiation is absorbed by the floating body through the cooling element and the static coil connected to the cooling element.

According to the invention, the static coil has a superconducting conductor loop made of a superconducting strip material extending from it. The proposed conductor loop makes it possible for the coil to be energized in a contactless manner through the wall of the cryostat via the electrical generator arranged in the immediate vicinity and outside of the cryostat. By using the superconducting electrical generator, the coil can be easily energized and charged through the wall of the cryostat. This avoids thermal losses caused by the electrical supply lines and connections between the static coil and the electrical generator that are usually required.

In order to maximize the magnetic flux density generated, it can advantageously be provided that the electrical generator has a Halbach magnet arrangement. In a Hallbach magnet arrangement, the rotationally symmetrical and targeted alignment of the poles of the permanent magnets enables a magnetic concentration and thus amplification of the magnetic flux density in the area of the superconducting conductor loop arranged in the cryostat, thereby improving the current supply to the static coil.

By combining a seamless static coil with a superconducting electrical generator, it is possible that, due to the very low ohmic losses, the electrical generator can be switched off after reaching the desired coil current or the desired levitation force or the required floating state and floating distance and only to change the Coil current must be switched on again. This provides a cost-saving and efficient superconducting bearing arrangement with high efficiency.

The bearing arrangement according to the invention also has at least one floating body which is made of a superconducting material and advantageously of segments of a superconducting strip material. The floating body is arranged at least partially in the magnetic field generated by the static coil, in this respect in the coil core and in the area of the end face of the static coil.

According to the invention, the floating body is connected to a coupling element. The coupling element serves in particular as a connection option between the floating body and at least one further component, for example with a flywheel memory. It can be provided that the coupling element is passed through the cryostat and enables connection to another component outside the cryostat. It is also conceivable that the coupling element is provided within the cryostat in a vacuum.

To avoid thermal losses and undesirable heat conduction from the coupling element to the floating body It is advantageously provided that, in particular in the case of a coupling element led out of the cryostat, this is made of a fiber-reinforced composite material which has a low thermal conductivity and thus hinders the thermal input into the cryostat.

To further improve the cooling of the floating body, it can advantageously be provided that a structural element with a similarly designed cooling structure is arranged between the coupling element and the floating body. The structural element and the similarly designed cooling structure can advantageously be designed in a meandering shape to increase their surface area in order to enable particularly effective cooling of the structural element and thus of the floating body by means of the proposed radiation cooling. The aim of the structural element is to counteract the undesirable thermal input that may occur via the coupling element in the cryostat and to achieve longer cooling and function of the floating body.

In an advantageous embodiment, the proposed superconducting bearing arrangement can be provided with a thermal insulation element which is positioned between the floating body and the cooling device. The technical effect of a thermal insulation element is that the cooling of the floating body is delayed compared to the static coil, so that the static coil first reaches the superconducting state and only then do the floating bodies.

• - ein supraleitendes Bandmaterial sowohl für die statische Spule wie auch den schwebend lagerbaren Körper eingesetzt wird, wodurch die Lageranordnung kostengünstig ist,
• - thermische und ohmsche Verluste stark reduziert werden, da im Wesentlichen elektrische Verbindungsleitungen und Kontakte vermieden werden,
• - über die kontaktlose Bestromung der statischen Spule über den elektrischen Generator der Schwebezustand des schwebend lagerbaren Körpers variabel beeinflusst und eigestellt werden kann,
• - durch den erstmaligen Einsatz einer Strahlungskühlung auf eine aufwendige und kostenintensive Helium-Kühlvorrichtung verzichtet wird,
• - durch den Einsatz einer nahtlosen statischen Spule, deren Wicklungen aus einem supraleitenden Bandmaterial gefertigt sind, eine signifikante Steigerung der Levitationskraftdichte und der magnetischen Flussdichte erreicht und auf kostenintensive Permanentmagnete verzichtet werden kann.

In summary, the superconducting bearing arrangement according to the invention has the technical advantages and effects that:

• - a superconducting strip material is used for both the static coil and the floating body, making the bearing arrangement cost-effective,
• - thermal and ohmic losses are greatly reduced, since electrical connecting lines and contacts are essentially avoided,
• - the floating state of the floating body can be variably influenced and adjusted via the contactless current supply to the static coil via the electrical generator,
• - the first use of radiation cooling eliminates the need for a complex and cost-intensive helium cooling device,
• - By using a seamless static coil, the windings of which are made of a superconducting strip material, a significant increase in the levitation force density and the magnetic flux density can be achieved and expensive permanent magnets can be dispensed with.

The invention is explained in more detail below using an exemplary embodiment, with the associated 1 shows an example of the schematic structure of the superconducting bearing arrangement in cross section.

Embodiment example

According to 1 A rotating superconducting bearing arrangement is shown, the components of which are essentially arranged in a cryostat 1. The static coil 4 and the cooling structure 6 are connected via copper wires to the cooling element 7, which is a cold head. A floating body 4, which is T-shaped in cross section and is a rotor, is arranged in the coil core of the static coil 3 and in its end region and placed on a thermal insulation element 11. The rotor is connected to a structural element 9 made of glass fiber reinforced plastic and having a meandering cross-section, which is surrounded by a similarly designed cooling structure 6 made of copper. The coupling element 10 is connected to the structural element 9 and led out of the cryostat 1. The static coil 3 has windings made of the superconducting rare earth-barium-copper oxide strip material, the windings of the static coil 3 being manufactured seamlessly. The static coil 3 has a conductor loop 5 formed from the same superconducting strip material, which extends from the static coil 3 to the cryostat wall and is directed to an electrical generator 2 in the form of a dynamo arranged outside the cryostat 1. The dynamo 2, which is arranged in the immediate vicinity of the conductor loop 5 and adjacent to it, has permanent magnets in a Halbach arrangement.

To produce the floating state of the bearing, the cold head cooling element 7 first cools both the superconducting static coil 3 and the floating rotor 4, with the floating rotor 4 resting on the thermal insulation element 11. The thermal insulation element 11 slows down the cooling of the later floating rotor 4 compared to the static coil 3, so that the static coil 3 reaches the critical transition temperature before the rotor 4 and first becomes superconducting. As soon as the critical transition temperature in the static coil 3 is reached, it can be energized through the wall of the cryostat 1 without contact through the interaction of the dynamo 2 and the superconducting conductor loop 5. First, the static coil 3 is only supplied with a portion of the maximum possible current. Subsequently, further cooling is carried out and the rotor 4 is cooled below its transition temperature, so that the generated and set magnetic field of the static coil 3 is stored. After both the static coil 3 and the rotor 4 have reached the critical transition temperature and are superconducting, the speed of the dynamo 2 and thus the energization of the coil current is further increased. Due to the magnetic flux density generated by the static coil 3, the rotor 1 lifts off from the thermal insulation element 11 and floats without contact. The gap between rotor 4 and static coil 3 can be variably adjusted by changing the coil current. After the required flying height of the rotor 4 or the desired levitation force has been reached, the dynamo 2 can be switched off. The floating rotor 4 and the meandering structural element 9 are cooled via the cooling structure 6 by the radiation generated between its surface and the static coil 3. As a result, the heat introduced via the coupling element 10 is dissipated along the structural element 9 from the rotor 4 by radiation, so that the floating rotor 4 remains cooled below its critical transition temperature.

Reference symbol list

1

Cryostat

2

Electric generator

3

Static coil

4

Floating body

5

Conductor loop

6

Cooling structure

7

Cooling element

8th

Cooling device

9

Structural element

10

Coupling element

11

Thermal insulation element

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009049889 A1 [0006]
• DE 102010004904 A1 [0007]
• DE 102017212675 A1 [0008]
• DE 1020182217983 A1 [0009]

Claims (10)

Superconducting bearing arrangement, which has at least one cryostat (1), in which at least one short-circuited static coil (3) made of a superconducting strip material with a conductor loop (5) extending from the static coil (3), at least one superconducting strip material and Floating body (4), at least one radiation-emitting cooling device (8) with a connected cooling element (7), at least one coupling element (10) and at least one electrical generator (2) arranged outside the cryostat (1), the floatingly storable Body (4) is connected to the coupling element (10) and is arranged at least partially in the coil core and in the area of the end face of the static coil (3), and wherein the static coil (3) is powered by the electrical generator (2) via the conductor loop (5) can be powered without contact. Superconducting bearing arrangement according to Claim 1 , in which a structural element (9) is arranged between the coupling element (10) and the floating body, which is surrounded by a similarly designed cooling structure (6). Superconducting bearing arrangement according to Claim 2 , in which the structural element (9) and the cooling structure (6) are meandering. Superconducting bearing arrangement according to one of the preceding claims, in which at least the floating body (4) is formed from segments of the superconducting strip material. Superconducting bearing arrangement according to one of the preceding claims, in which the cooling element (7) is a cold head component. Superconducting bearing arrangement according to one of the preceding claims, in which the superconducting strip material of the floating body (4) at least partially has a first surface coating and the superconducting strip material of the static coil (3) and / or the cooling element (7) at least partially has a second surface coating, whose emissivity levels are different. Superconducting bearing arrangement according to Claim 6 , in which the emissivity of the first surface coating is greater than the emissivity of the second surface coating. Superconducting bearing arrangement according to one of the preceding claims, in which the electrical generator (2) has a Halbach magnet arrangement. Superconducting bearing arrangement according to one of the preceding claims, in which the coupling element (10) is made from a fiber-reinforced composite material. Superconducting bearing arrangement according to one of the preceding claims, in which at least one thermal insulation element (11) is arranged between the floating body (4) and the cooling device (8).

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