阅读说明：本技术 具有电磁保护部件的超导磁体 (Superconducting magnet with electromagnetic protection component ) 是由 周伟 毛凯 张艳清 翟茂春 谭浩 张志华 李超 刘伟 王岩 胡良辉 于 2019-04-24 设计创作，主要内容包括：本发明涉及电磁技术领域,公开了一种具有电磁保护部件的超导磁体。其中,该超导磁体包括超导线圈、冷屏,超导磁体外壳和屏蔽装置,所述冷屏设置在所述超导线圈外,所述超导磁体外壳设置在所述冷屏外且与所述冷屏相距预定距离,所述屏蔽装置设置在所述超导磁体外壳与外部磁体之间,所述屏蔽装置用于屏蔽所述外部磁体的谐波磁场并允许所述外部磁体的基频磁场进入所述超导线圈,基频磁场与所述超导线圈的直流磁场相互作用产生推力。由此,可以有效地防止高频磁场进入超导线圈,同时能够简化超导磁体本体内部结构,有效缓解超导磁体本体内部结构紧凑的压力,提高超导磁体运行的安全性。(The invention relates to the technical field of electromagnetism, and discloses a superconducting magnet with an electromagnetic protection component. The superconducting magnet comprises a superconducting coil, a cold screen, a superconducting magnet shell and a shielding device, wherein the cold screen is arranged outside the superconducting coil, the superconducting magnet shell is arranged outside the cold screen and is away from the cold screen by a preset distance, the shielding device is arranged between the superconducting magnet shell and an external magnet, the shielding device is used for shielding a harmonic magnetic field of the external magnet and allowing a fundamental frequency magnetic field of the external magnet to enter the superconducting coil, and the fundamental frequency magnetic field interacts with a direct current magnetic field of the superconducting coil to generate thrust. Therefore, the high-frequency magnetic field can be effectively prevented from entering the superconducting coil, the internal structure of the superconducting magnet body can be simplified, the pressure of the internal structure of the superconducting magnet body is effectively relieved, and the running safety of the superconducting magnet is improved.)

1. A superconducting magnet with electromagnetic protection components, characterized in that it comprises a superconducting coil (6), a cold shield (5), a superconducting magnet housing (4) and a shielding device (2), the cold shield (5) is arranged outside the superconducting coil (6), the superconducting magnet housing (4) is arranged outside the cold shield (5) and at a predetermined distance from the cold shield (5), the shielding device (2) is arranged between the superconducting magnet housing (4) and an external magnet (1), the shielding device (2) is used for shielding harmonic magnetic fields of the external magnet (1) and allowing a fundamental frequency magnetic field of the external magnet (1) to enter the superconducting coil (6), the fundamental frequency magnetic field interacts with a direct current magnetic field of the superconducting coil (6) to generate thrust.

2. A superconducting magnet with electromagnetic protection components according to claim 1, further comprising a support connection (3), the shielding device (2) being arranged on the superconducting magnet housing (4) through the support connection (3).

3. A superconducting magnet with an electromagnetic protection component according to claim 2, wherein the shielding arrangement (2) comprises a plurality of shielding layers stacked and spacers disposed between the shielding layers.

4. A superconducting magnet with an electromagnetic protection component according to claim 3, wherein the material of the plurality of shielding layers is a high electrical conductivity material.

5. A superconducting magnet with an electromagnetic protection component according to claim 3, wherein the material of two outermost shield layers of the plurality of shield layers is different from the material of the other shield layers between the two outermost shield layers.

6. A superconducting magnet with electromagnetic protection components according to claim 5, wherein the material of the two outermost shield layers is a high electrical conductivity material and the material of the other shield layers is a high magnetic conductivity material.

7. A superconducting magnet with electromagnetic protection components according to claim 4 or 6, wherein the high electrical conductivity material comprises copper and aluminum.

8. A superconducting magnet with electromagnetic protection components according to any of claims 2-6, characterized in that the material of the support connection (3) is a non-magnetic conducting material.

9. A superconducting magnet with an electromagnetic protection component according to claim 8, wherein the non-magnetic conductive material comprises titanium alloy and stainless steel.

10. A superconducting magnet with electromagnetic protection components according to any of claims 2-6, characterized in that the supporting connection (3) is welded or screwed with the shielding (2) and the superconducting magnet housing (4).

Technical Field

The invention relates to the technical field of electromagnetism, in particular to a superconducting magnet with an electromagnetic protection component.

Background

The superconducting magnet has the advantages of large generated magnetic field, small volume, light weight, low loss and the like, and is often applied to the fields of ultrahigh-speed environments, such as ultrahigh-speed maglev trains, ultrahigh-speed electromagnetic ejection, high-speed three-dimensional reservoirs and the like. In particular to an ultra-high-speed maglev train, a superconducting magnet is a rotor part of a superconducting linear motor, a stator part of the superconducting linear motor is formed by winding a normally conductive coil, the superconducting magnet of the rotor part is electrified with direct current, the normally conductive magnet of the stator part is electrified with alternating current, a direct current magnetic field of the superconducting magnet interacts with an alternating current magnetic field of the normally conductive magnet, electromagnetic force is generated in the superconducting magnet, the superconducting magnet has certain thrust in the motion direction, and therefore the superconducting magnet generates certain acceleration.

The superconducting material has a zero resistance characteristic, that is, when the superconducting material is introduced with direct current, the voltage at two ends of the superconducting material is zero, that is, no power loss exists, but when the superconducting material is introduced with alternating current or is in an alternating external magnetic field, certain power loss can be generated due to the magnetic flux pinning effect of the superconducting material, which is generally called as alternating current loss.

The input current of the normal magnetic field of the superconducting linear motor is provided by the converter, and due to the design error of the converter and the consideration of the practical engineering application of the superconducting linear motor, the magnetic field generated by the normal magnetic field not only has a fundamental magnetic field, but also contains a considerable part of harmonic magnetic field, wherein the fundamental magnetic field and the superconducting magnet interact to generate required thrust, but the harmonic magnetic field enters the superconducting magnet, so that the alternating current loss of the superconducting magnet is increased, the risk of quenching of the superconducting magnet is increased, and the harmonic magnetic field also interacts with the direct current magnetic field of the superconducting magnet to generate unnecessary thrust pulsation, and the quenching can be caused by overlarge vibration quantity of the superconducting magnet.

Not only a superconducting linear motor, but also other superconducting magnets often do not need the magnetic field of harmonic waves and need to be shielded, so that an electromagnetic protection measure needs to be taken for the superconducting magnet, and the measure can not only enable the magnetic field below a certain frequency to enter the superconducting magnet, but also prevent the magnetic field above the certain frequency from entering the superconducting magnet.

At present, a superconducting magnet is often shielded from the harmonic wave of a superconducting coil by a cold shield device. The cold shield is made of high-conductivity aluminum or copper, and is placed inside the superconducting magnet, namely in a vacuum layer between an inner dewar and an outer dewar of the superconducting coil, and is a shell structure with a certain thickness, and the superconducting coil is completely wrapped, and the thickness is related to the frequency of a magnetic field to be shielded and the conductivity and permeability of the cold shield material. The cold shield can prevent a magnetic field with more than a certain frequency from entering the superconducting coil, and can also properly reduce the heat radiation of the system, reduce the heat leakage of the magnet system and increase the reliability of the superconducting magnet.

However, the current method of electromagnetic protection using a cold shield has the following disadvantages: (1) the cold shield structure needs to be placed inside the superconducting magnet, but in the super-high-speed superconducting magnet, the internal structure is very compact generally, the cold shield is not easy to place, and the thickness of the cold shield is thicker when the frequency of a magnetic field needing to be shielded by the superconducting magnet is lower, so that the total assembly difficulty of the superconducting magnet is increased, and the weight of the superconducting magnet is also increased; (2) in an ultrahigh-speed high-load environment, the fixing and the structural reinforcement of the cold shield are difficult; (3) because the inner space of the super-high-speed superconducting magnet is limited, after the superconducting magnet is vacuumized, the outer Dewar shrinks inwards to possibly contact with the cold shield, so that excessive heat leakage is caused, and quench is easily caused. The requirement of shielding the high frequency magnetic field may not be met by merely placing a cold shield inside the superconducting magnet. In the application of an ultra-high-speed environment, the weight and heat leakage of the superconducting magnet are very important indexes, and if the superconducting magnet is overweight or has overlarge heat leakage, the speed of the superconducting magnet is likely to fail to meet the design requirement and even directly cause quench.

Disclosure of Invention

The invention provides a superconducting magnet with an electromagnetic protection component, which can solve the technical problem that the speed of the superconducting magnet in the prior art cannot meet the design requirement and even directly causes quench.

The invention provides a superconducting magnet with an electromagnetic protection component, wherein the superconducting magnet comprises a superconducting coil, a cold screen, a superconducting magnet shell and a shielding device, the cold screen is arranged outside the superconducting coil, the superconducting magnet shell is arranged outside the cold screen and is away from the cold screen by a preset distance, the shielding device is arranged between the superconducting magnet shell and an external magnet, the shielding device is used for shielding a harmonic magnetic field of the external magnet and allowing a fundamental frequency magnetic field of the external magnet to enter the superconducting coil, and the fundamental frequency magnetic field interacts with a direct current magnetic field of the superconducting coil to generate thrust.

Preferably, the superconducting magnet further comprises a supporting connector, and the shielding device is arranged on the superconducting magnet shell through the supporting connector.

Preferably, the shielding means comprises a plurality of shielding layers stacked and spacers disposed between the shielding layers.

Preferably, the material of the plurality of shield layers is a high conductivity material.

Preferably, the material of two outermost shield layers of the plurality of shield layers is different from the material of the other shield layers between the two outermost shield layers.

Preferably, the material of the two outermost shield layers is a high electrical conductivity material, while the material of the other shield layers is a high magnetic conductivity material.

Preferably, the high conductivity material includes copper and aluminum.

Preferably, the material of the support connector is a non-magnetic material.

Preferably, the non-magnetic conductive material includes titanium alloy and stainless steel.

Preferably, the supporting connector is welded or screwed to the shielding device and the superconducting magnet housing.

According to the technical scheme, the cold screen can be arranged outside the superconducting coil, the superconducting magnet shell which is arranged outside the cold screen and has a preset distance with the cold screen is arranged outside the cold screen, the shielding device is arranged between the superconducting magnet shell and the external magnet, the harmonic magnetic field of the external magnet can be shielded through the shielding device, and the fundamental frequency magnetic field of the external magnet is allowed to enter the superconducting coil, so that the fundamental frequency magnetic field and the direct current magnetic field of the superconducting coil interact to generate thrust. That is, when the superconducting magnet is in an ultra-high speed, high load and high vibration environment, the shielding device can effectively prevent a high-frequency magnetic field from entering the superconducting coil, and the shielding device is arranged outside the superconducting magnet shell, so that the weight of the superconducting magnet body can be reduced, the internal structure of the superconducting magnet body is simplified, the pressure of the internal structure of the superconducting magnet body is effectively relieved, and the running safety of the superconducting magnet is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

Fig. 1 is a schematic diagram of a superconducting magnet having an electromagnetic protection component according to an embodiment of the present invention;

FIG. 2 is a schematic view of a shielding apparatus according to an embodiment of the present invention;

FIG. 3 is a graphical representation of the required thickness of different materials at the frequency to be shielded according to an embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

Fig. 1 is a schematic diagram of a superconducting magnet with electromagnetic protection components according to an embodiment of the invention.

As shown in fig. 1, an embodiment of the present invention provides a superconducting magnet having an electromagnetic protection component, wherein the superconducting magnet comprises a superconducting coil 6, a cold shield 5, a superconducting magnet housing 4 and a shielding device 2 (in other words, the superconducting magnet may comprise a superconducting magnet body and a shielding device 2, the superconducting magnet body may comprise the superconducting coil 6, the cold shield 5 and the superconducting magnet housing 4), the cold shield 5 is arranged outside the superconducting coil 6, the superconducting magnet shell 4 is arranged outside the cold shield 5 and is at a preset distance from the cold shield 5, the shielding device 2 is disposed between the superconducting magnet housing 4 and the external magnet 1, and the shielding device 2 is configured to shield a harmonic magnetic field of the external magnet 1 and allow a fundamental frequency magnetic field of the external magnet 1 to enter the superconducting coil 6, where the fundamental frequency magnetic field interacts with a direct current magnetic field of the superconducting coil 6 to generate thrust.

That is, the shielding device can prevent the high-frequency harmonic magnetic field of the external magnet from entering the superconducting coil while allowing the fundamental frequency magnetic field of the external magnet to enter the superconducting coil, and interact with the direct-current magnetic field of the superconducting coil to generate thrust.

The external magnet may be a normal conducting magnet or a superconducting magnet, but the present invention is not limited thereto. For example, as long as the external magnet can generate an alternating magnetic field, the superconducting magnet having the electromagnetic protection member according to the present invention can shield a high-frequency harmonic magnetic field thereof.

The normally conductive magnet is generally formed by winding a copper wire, and a high-frequency alternating current can be introduced to generate a high-frequency alternating magnetic field.

According to the technical scheme, the cold screen can be arranged outside the superconducting coil, the superconducting magnet shell which is arranged outside the cold screen and has a preset distance with the cold screen is arranged outside the cold screen, the shielding device is arranged between the superconducting magnet shell and the external magnet, the harmonic magnetic field of the external magnet can be shielded through the shielding device, and the fundamental frequency magnetic field of the external magnet is allowed to enter the superconducting coil, so that the fundamental frequency magnetic field and the direct current magnetic field of the superconducting coil interact to generate thrust. That is, when the superconducting magnet is in an ultra-high speed, high load and high vibration environment, the shielding device can effectively prevent a high-frequency magnetic field from entering the superconducting coil, and the shielding device is arranged outside the superconducting magnet shell, so that the weight of the superconducting magnet body can be reduced, the internal structure of the superconducting magnet body is simplified, the pressure of the internal structure of the superconducting magnet body is effectively relieved, and the running safety of the superconducting magnet is improved.

According to an embodiment of the invention, the superconducting coil may be wound from a superconducting material. The superconducting coils are energized with a direct current to generate a direct magnetic field and can interact with an alternating magnetic field generated by an external magnet (e.g., a normally conductive magnet) to generate thrust.

The superconducting material may include a high temperature superconducting material and a low temperature superconducting material, among others. For example, the high temperature superconducting material may include a strip such as Bi2223 and YBCO, and the low temperature superconducting material may include a wire such as NbTi and Nb3 Sn.

According to an embodiment of the present invention, the superconducting magnet with electromagnetic protection components further includes a supporting connector 3, and the shielding device 2 is disposed on the superconducting magnet housing 4 through the supporting connector 3.

That is, the shielding apparatus may be connected with the superconducting magnet using a supporting connection.

Alternatively, the shielding device 2 of the present invention may not be connected by the supporting rod 3, that is, the shielding device does not move simultaneously with the superconducting magnet, but the shielding device is completely laid on the moving track of the superconducting magnet, so as to achieve the purpose of superconducting magnetic shielding.

Fig. 2 is a schematic diagram of a shielding apparatus according to an embodiment of the present invention.

According to an embodiment of the present invention, as shown in fig. 2, the shielding apparatus 2 may include a plurality of shielding layers stacked and a spacer (not shown) disposed between the shielding layers.

For example, the spacers may be G10 thin pieces (used to space and support the shields and prevent the shields from being forced together) that may be connected to each shield by bolts (not shown).

By adopting the shielding device comprising a plurality of shielding layers, the external high-frequency magnetic field can be shielded more effectively, namely the shielding effect is improved.

The shielding device 2 is shown in fig. 2 to comprise 4 shielding layers, but it will be understood by those skilled in the art that the number of layers shown in fig. 2 is merely exemplary and not intended to limit the present invention. The number of shielding layers can be determined by those skilled in the art according to practical situations.

According to one embodiment of the invention, the material of the plurality of shielding layers is a high conductivity material.

That is, the material of all the shield layers may be a high conductivity material. For example, each of the shielding layers may be a thin plate made of a high-conductivity material, which is a thin plate without holes or slits.

Wherein the high conductivity material may also have a low permeability.

According to one embodiment of the invention, the material of two outermost shield layers of the plurality of shield layers is different from the material of the other shield layers between the two outermost shield layers.

According to one embodiment of the invention, the material of the two outermost shield layers is a high electrical conductivity material, while the material of the other shield layers is a high magnetic conductivity material.

For example, referring to FIG. 2, and taking FIG. 2 as an example, the two outer layers may be made of high conductivity materials to enhance the emission; and the inner layer (2 inner layers) between the two outer layers can adopt a high-permeability material so as to increase the eddy current effect.

According to one embodiment of the invention, the high conductivity material comprises copper and aluminum (i.e., a shielding material).

Alternatively, the shielding device 2 may also comprise only one shielding layer (e.g. one sheet of a high conductivity material). By way of example, the shielding capability may be adjusted by varying the material and/or thickness of the one shielding layer (see description below with respect to fig. 3).

According to an embodiment of the present invention, the material of the support connector 3 may be a non-magnetic material (e.g., a high strength non-magnetic material).

The non-magnetic conductive material may include titanium alloy and stainless steel (e.g., 316L stainless steel), among others.

According to an embodiment of the present invention, the supporting connector 3 is welded or screwed with the shielding device 2 and the superconducting magnet housing 4.

Wherein the supporting connecting member 3 may be a supporting rod.

Therefore, the shielding device 2 can be fixed on the superconducting magnet shell 4 through the supporting connecting piece, and in the process of high-speed movement of the superconducting magnet, the shielding device 2 can move along with the superconducting magnet body, so that the shielding device is always positioned between the superconducting magnet body and an external magnet, and the reliability of the shielding device 2 is improved.

In the embodiment of the present invention, the cold shield 5 is an essential part of a general superconducting magnet, and similar to the shielding device 2, the cold shield 5 may be made of a high-conductivity and low-permeability material. Wherein, the cold shield 5 can be connected with the superconducting magnet shell 4 through bolts.

The cold shield 5 can reduce the heat radiation of the superconducting magnet system (especially in the low-temperature superconducting magnet in the liquid helium environment, the heat radiation is a main reason for influencing heat leakage in the refrigeration process and the stable operation process of the low-temperature superconducting magnet, so that the cold shield is required to reduce the heat radiation), and can further prevent the high-frequency harmonic magnetic field of an external magnet from entering the superconducting coil on the basis of the shielding device 2. That is, the shielding device 2 outside the superconducting magnet body can directly shield the high-frequency harmonic magnetic field of the external magnet, and the original thinner cold shield can be continuously retained in the superconducting magnet body to reduce the heat radiation, and at the same time, the frequency magnetic field which is not completely shielded by the shielding device 2 (such as shielding the external magnetic field on the upper and lower surfaces of the superconducting coil) can be shielded, so as to further improve the shielding effect.

In other words, the shielding device can shield most of the high-frequency magnetic field; the cold shield can shield a magnetic field with higher frequency, and can shield a magnetic field which can not be shielded by most of the shielding devices, for example, magnetic lines of force of some high-frequency magnetic fields bypass the shielding devices and pass through the magnetic field entering from the upper surface and the lower surface of the superconducting magnet (superconducting magnet body), and the magnetic field can be shielded by the cold shield.

FIG. 3 is a graphical representation of the required thickness of different materials at the frequency to be shielded according to an embodiment of the present invention.

The shielding of the high-frequency magnetic field is to prevent the external high-frequency magnetic field from entering a certain area, when the high-frequency electromagnetic wave is emitted to the surface of a conductor and enters the surface, it will induce a high-frequency alternating current in the conductor, which will excite a new electromagnetic wave, the newly excited electromagnetic wave will be opposite in phase to the incident electromagnetic wave in the conductor, and the current generation in the conductor will cause the consumption of the energy of the incident wave field, so that the total electromagnetic field in the conductor will be attenuated substantially exponentially with the depth, which is generally called the penetration depth. The penetration depth is calculated as:

where, f is the frequency of the incident magnetic field, μ is the permeability of the shielding material, and σ is the conductivity of the shielding material. As can be seen from the formula (1), the higher the frequency, the higher the electrical conductivity, the higher the magnetic conductivity and the smaller the penetration depth, and when the thickness of the shielding material is greater than the penetration depth, the shielding material has a good electromagnetic shielding effect. Conversely, if the frequency range of the incident magnetic field is to be shielded, the thickness of the shielding material will be thicker, otherwise. Fig. 3 shows the material thickness relationship required for different shielding materials at the shielded frequency, and as can be seen from fig. 3, the thickness of the copper shield layer is thinner than that of aluminum under the same frequency magnetic field, because of the higher conductivity of copper. On the other hand, the lower the frequency to be shielded, the thicker the thickness of the shielding material required. For example, in some ultra-high-speed superconducting magnet applications, such as ultra-high-speed superconducting linear motors, the fundamental magnetic field of a normal superconducting magnet is generally below 300Hz, and the magnetic field above 300Hz is preferably shielded, and the thickness of the shielding material (the thickness of the shielding device) can be determined to be at least 4mm according to formula (1).

It will be appreciated by persons skilled in the art that the above description with respect to fig. 3 is merely exemplary and not intended to limit the present invention.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and in the case of not making a reverse description, these orientation words do not indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.