The invention belongs to the technical field of superconducting magnet excitation systems, and particularly relates to a high-temperature superconducting flux pump system.
Compared with traditional permanent magnets and common electromagnets, superconducting magnets, as an important part in the superconducting power application field, have a low weight, small size and extremely low loss, can generate a higher-intensity magnetic field, and are applied to the medical field, energy field and traffic field because of their superiorities.
At present, the development difficulty of superconducting magnets is that high-temperature superconducting coils cannot operate in a continuous current mode. The failure to completely eliminate the current loss caused by flux creep and welding resistance leads to nonnegligible current attenuations of high-temperature superconducting closed circuits.
Existing flux pumps can magnetize superconducting loads without establishing a contact-type current lead between a low-temperature environment and a normal-temperature environment, thus cutting off heat connection between the low-temperature environment and the non-low-temperature environment.
However, traditional flux pumps have a low charging rate, a complex structure and other defects.
To solve the abovementioned technical problems, the invention discloses a high-temperature superconducting flux pump system, which has a simpler structure, a charging current of thousands of amperes, and a lower power cost on the premise of not changing the magnet structure and winding cost. The specific technical solution of the invention is as follows:
A high-temperature superconducting flux pump system comprises:
A flux pump body;
A superconducting load; and
A stator group comprising at least one stator;
Wherein, the flux pump body has an air gap for receiving the stator group, and the superconducting load and the stator group are connected to form a closed circuit.
Preferably, the flux pump body comprises:
An alternating-current winding;
A direct-current winding disposed at one or two ends of the alternating-current winding; and
A first magnetic yoke;
Wherein, when the direct-current winding is disposed at one end of the alternating-current winding, the magnetic yoke has an end connected to the direct-current winding, as well as an end extending to the other end, away from the direct-current winding, of the alternating-current winding;
When the direct-current windings are disposed at the two ends of the alternating-current winding, the magnetic yoke has an end connected to the direct-current winding located at one end of the alternating-current winding, as well as an end connected to the direct-current winding at the other end of the alternating-current winding, such that a magnetic circuit is formed when a flux pump operates; and the number of the direct-current windings at one end of the alternating-current winding is the same as the number of the direct-current windings at the other end of the alternating-current winding;
The air gap for receiving the stator group is located between the alternating-current winding and the first magnetic yoke.
Preferably, the superconducting load has an inlet terminal and an outlet terminal, and two ends of the stator group are connected to the inlet terminal and the outlet terminal respectively to form a closed circuit.
Preferably, the high-temperature superconducting flux pump system comprises at least two superconducting loads, and each of the superconducting loads has an inlet terminal and an outlet terminal; and the inlet terminal and the outlet terminal of each of the superconducting loads are connected to the stator group to form a closed circuit.
Preferably, the flux pump body comprises two magnetic yokes, which are located at two ends of the alternating-current winding in a length direction respectively and are connected to the direct-current windings at the two ends of the alternating-current winding respectively, such that two magnetic circuits are formed when the flux pump operates;
Wherein, the high-temperature superconducting flux pump system comprises two stator groups which are located in different air gaps, and the two stator groups are connected in parallel and are then connected to the superconducting load to form a closed circuit.
Preferably, the two stator groups connected in parallel have two connecting terminals, and the inlet terminal and the outlet terminal are connected to the two connecting terminals respectively.
Preferably, each stator group comprises at least two stators, and all the stators in each stator group are arranged in parallel; the two stator groups connected in parallel have an even number of connecting terminals, which is at least two; each of the connecting terminals comprises two parts, wherein one part is connected to the inlet terminal and the other part is connected to the outlet terminal.
Preferably, the superconducting load comprises N individual loads, wherein N≥2, and N is an even number;
The high-temperature superconducting flux pump system comprises two stator groups, and each stator group comprises N/2 stators;
In the superconducting load, N/2 individual loads are in one-to-one correspondence with the stators in one stator group and are connected to the stators to form a closed circuit; and the other N/2 individual loads are in one-to-one correspondence with the stators in the other stator group and are connected to the stators to form a closed circuit.
Preferably, the superconducting load comprise M individual loads, wherein M≥3, and M is an odd number;
The high-temperature superconducting flux pump system comprises two stator groups, wherein one of the two stator groups comprises (M−1)/2 stators, and the other stator group comprises (M+1)/2 stators;
In the superconducting load, (M−1)/2 individual loads are in one-to-one correspondence with the stators in one stator group and are connected to the stators to form a closed circuit; and the other (M+1)/2 individual loads are in one-to-one correspondence with the stators in the other stator group and are connected to the stators to form a closed circuit.
Preferably, the flux pump body comprises two first magnetic yokes, which are located at two ends of the alternating-current winding in a length direction respectively and are connected to the direct-current windings at the two ends of the alternating-current winding respectively, such that two magnetic circuits are formed when the flux pump operates;
The high-temperature superconducting flux pump system comprises two superconducting loads which are located at the two ends of the alternating-current winding in the length direction respectively, and each of the two superconducting loads is connected to the stator group at the same end, such that two closed circuits are formed.
Compared with the prior art, the stator group can realize contactless excitation of the superconducting load by means of the alternating-current winding and the direct-current winding; wherein, the direct-current winding is supplied with power by a direct-current power source, and the amplitude of direct current can be regulated; the alternating-current winding is supplied with power by a three-phase variable-frequency inverter, and the amplitude and frequency of alternating current can be regulated; the system generates a direct-current biased traveling wave magnetic field through the flux pump body to enable the alternating-current winding to generate a standard sinusoidal magnetic field and the direct-current winding to generate a biased direct-current magnetic field, such that the system of the invention optimizes the charging rate with a simple structure, and effectively and obviously provides a higher charging rate with a low cost and high efficiency; in addition, the invention provides a contactless excitation system which can realize superconducting direct-current output of thousands of amperes.
In the figures: 100, flux pump body; 101, alternating-current winding; 1011, socket; 102, direct-current winding; 103, first magnetic yoke; 104, second magnetic yoke; 200, superconducting load; 201, individual load; 300, stator group; 301, stator; 400, air gap; 500, wide stator.
To allow those skilled in the art to have a better understanding of the technical solution of the invention, the invention will be described in further detail below in conjunction with specific embodiments.
To gain a good understanding of the technical solution of the invention, a superconducting load 200 is used for explanation in the following embodiments. It can be understood that the superconducting load may be a superconducting cable, or the like.
As shown in
In this embodiment, the individual load 201 and the stator 301 are provided with high-temperature superconducting strips, which are specifically ReBCO strips. The high-temperature superconducting strip is formed by a hastelloy layer, a ReBCO layer and a buffer layer which are stacked on a substrate sequentially from bottom to top, and has an operating temperature not higher than 77K, wherein Re is rare earth. Wherein, the superconducting load 200 is a double-pancake coil group, and the individual load 201 is a double-pancake coil, that is to say, the superconducting load 200 is formed by at least one individual load 201.
In this embodiment, the individual load 201 may be a traditional circular individual load 201 or a track-type individual load 201 similar to a standard 400 M track; and in addition to the double-pancake coil, the individual load 201 may be different types of single-pancake coils, which will not be detailed below.
To facilitate the use of this embodiment, the flux pump body 100 comprises an alternating-current winding 101, direct-current windings 102 and a first magnetic yoke 103, wherein the direct-current windings 102 are disposed at two ends of the alternating-current winding 101, and two ends of the first magnetic yoke 103 are connected to the direct-current windings 102 at the two ends of the alternating current 101 respectively, such that a magnetic circuit is formed when a flux pump operates; and the air gap 400 for receiving the stator group 300 is located between the alternating-current winding 101 and the first magnetic yoke 103.
The direct-current windings 102 are disposed at the two ends of the alternating-current winding 101; one end of the first magnetic yoke 103 is connected to the direct-current winding 102 at one end of the alternating-current winding 101, and the other end of the first magnetic yoke 103 is connected to the direct-current winding 102 located at the other end of the alternating-current winding 101, such that a magnetic circuit is formed when the flux pump operates; and the air gap 400 for receiving the stator group 300 is located between the alternating-current winding 101 and the first magnetic yoke 103.
In some other embodiments, the stator group 300 received in the air gap 400 may be located between the alternating-current winding 101 and the first magnetic yoke 103 and close to the first magnetic yoke 103 or the alternating-current winding 101.
It should be noted that the alternating-current winding 101 is provided with a socket 1011 for winding an alternating-current wire, so the air gap 400 for receiving the stator group 300 is located between the socket 1011 and the first magnetic yoke 103.
As shown in
It should also be noted that, in this embodiment, the number of the direct-current windings at one end of the alternating-current winding is the same as the number of the direct-current windings at the other end of the alternating-current winding to satisfy the requirement for symmetric application of magnetic fields.
In addition, as shown in
As shown in
In this embodiment, the superconducting load 200 is an individual load 201 or is formed by multiple individual loads 201, and no matter whether the superconducting load 200 is an individual load 201 or is formed by multiple individual loads 201, the superconducting load 200 has one inlet terminal and one outlet terminal, which are connected to the two ends of the stator group 300 respectively to form a complete closed circuit.
In this embodiment, multiple individual loads 201 of the superconducting load 200 are in seamless contact with each other, or are spaced from each other by a certain distance.
As shown in
In this embodiment, the superconducting load 200 comprises multiple individual loads 201. Different from the above embodiment where the individual loads 201 are integrated to ensure that the superconducting load 200 formed by the multiple individual loads 201 has one inlet terminal and one outlet terminal, each individual load 201 has an inlet terminal and an outlet terminal in this embodiment. Generally speaking, in this embodiment, the number of stators 301 in the stator group 300 is the same as the number of the individual loads 201; otherwise, the specific structure of this embodiment will be the same as that of above embodiment where the multiple individual loads 201 are integrated to ensure that the superconducting load 200 has one inlet terminal and one outlet terminal. On this basis, each stator 301 has two connecting terminals, which are connected to the inlet terminal and the outlet terminal of the corresponding individual load 201 respectively.
When the stator group 300 comprises multiple stators 301, the superconducting load 200 comprises multiple individual loads 201 and the number of the stators 301 is different from the number of the individual loads 201, the connection method in the above embodiment can still be used for connection. In this embodiment, every two adjacent stators 301 is spaced from each other by a proper distance, and such a design can also be used in the following embodiments.
The high-temperature superconducting flux pump system in all the above embodiments is a unilateral excitation system, that is, excitation is realized at only one end of the flux pump body 100. In the unilateral excitation system, each direct-current winding 102 comprises one direct-current coil. It should be noted that, in addition to the direct-current coil, each direct-current winding 102 also comprises a second magnetic yoke 104 connected to the first magnetic yoke 103. Therefore, it can be understood that in the direct-current winding 102, one end of the second magnetic yoke 104 is connected to the alternating-current winding 101, the other end of the second magnetic yoke 104 is connected to the first magnetic yoke 103, and the direct-current coil is wound on the second magnetic yoke 104. This design is also used in the following embodiments, and will not be detailed anymore.
It should be noted that, in some other embodiments, the second magnetic yoke 104 in the unilateral excitation system is connected to the alternating-current winding 101 to form a closed circuit, and in this case, the direct-current coil of the direct-current winding 102 may be wound on the first magnetic yoke 103 rather than the second magnetic yoke 104. Such a winding method can also be applied to the following embodiments, and will not be detailed anymore.
Based on any one of the above embodiments, excitation may be realized at both ends of the flux pump system, as shown in
It should be noted that, in any one embodiment, the first magnetic yoke 103 and/or the second magnetic yoke 104 may be made from iron, magnetically conductive metal such as cobalt or nickel, or magnetically conductive alloy. In this embodiment, the first magnetic yoke 103 and/or the second magnetic yoke 104 are/is made from iron.
In this embodiment, each direct-current winding 102 comprises two direct-current coils which are distributed at two ends of the direct-current winding 102 respectively, and in this case, the flux pump system is also a unilateral excitation system.
In this embodiment, each of the two ends of the flux pump body 100 is provided with one superconducting load 200 to realize excitation charging, such that the charging efficiency can be improved stably.
In addition, the unilateral excitation system is not a technical solution obtained simply by combining existing techniques. The inventor finds in actual study that the improvement of the charging efficiency of the excitation system is realized not merely by increasing or decreasing the number of the stators 301 and/or the number of the individual loads 201, and different combinations of the stators 301 and/or the individual loads 201 will also bring a different charging effect, and can remarkably improves the charging efficiency based on the prior art, without changing the magnet structure and winding cost. This is the same for a bilateral excitation system in the following embodiments.
To facilitate the use of this embodiment, a bilateral excitation system is provided on the basis of the unilateral excitation system.
That is, the flux pump system comprises two first magnetic yokes 103, which are located at the two ends of the alternating-current winding 101 in the length direction respectively and connected to the direct-current windings 102 at the two ends of the alternating-current winding 101 respectively, such that two magnetic circuits are formed when the flux pump operates; wherein, the flux pump system comprises two stator groups 300, which are located in different air gaps 400, and the two stator groups 300 are connected in parallel and then connected to the superconducting load 200 to form a closed circuit.
In this embodiment, each direct-current winding 102 comprises two direct-current coils, which are distributed at two ends of the direct-current winding 102 respectively. Compared with the unilateral excitation system with two closed circuits, the bilateral excitation system has only one closed circuit, which comprises two stator groups 300 connected in parallel, and a superconducting load 200 connected with the two stator groups 300.
As shown in
As shown in
In this embodiment, the two stator groups 300 connected in parallel have only two connecting terminals; the inlet terminal and the outlet terminal are the inlet terminal and the outlet terminal of the superconducting load 200, or the inlet terminal and the outlet terminal of multiple individual loads 201.
As shown in
Because the stator 301 can be connected to the superconducting load 200 to form a closed circuit only when the stator 301 has two connecting terminals, any one stator group 300 or stator 301 should have an even number of connecting terminals.
In this embodiment, the stator group 300 comprises a plurality of stators 301, wherein half of the stators 301 are integrated and the other half of the stators 301 are integrated to realize connection for forming a closed circuit.
Meanwhile, when the stator group 300 comprises only one stator 301 and the superconducting load 200 comprises multiple individual loads 201, the connection method in this embodiment can also be used. That is, the inlet terminals of all the individual loads 201 are integrated into one inlet terminal, and the outlet terminals of all the individual loads 201 are integrated into one outlet terminal, and then the inlet terminal and the outlet terminal are connected to the two connecting terminals of the stator 301 respectively.
When the stator group 300 comprises multiple stators 301, the superconducting load 200 comprises multiple individual loads 201 and the number of the stators 301 is different from the number of the individual loads 201, the connection method in the above embodiment can also be used.
As shown in
For example, in this embodiment, N is 10, that is, the superconducting load 200 comprises 10 individual loads 201, and each stator group 300 comprises 5 stators 301, and in this case, each individual load 201 has an inlet terminal and an outlet terminal, and each stator 301 has a connecting terminal; and the inlet terminals and outlet terminals of 5 individual loads 201 are connected to the connecting terminals of the 5 stators in one stator group 300, and the inlet terminals and outlet terminals of the other 5 individual loads 201 are connected to the connecting terminals of the 5 stators 301 in the other stator group 300 respectively.
So, when N is an even number such as 2, 4, . . . , 12, 14, . . . , the connection method in the above embodiment can also be used.
As shown in
For example, in this embodiment, M is 5, that is, the superconducting load 200 comprises 5 individual loads 201, one stator group 300 comprises 2 stators 301, and the other stator group 300 comprises 3 stators 301, and in this case, each individual load 201 has an inlet terminal and an outlet terminal, each stator 301 has a connecting terminal, the inlet terminals and outlet terminals of 2 individual loads 201 are connected to the two stators 301 comprising two stators 301 respectively, and the inlet terminals and outlet terminals of the other 3 individual loads 201 are connected to the three stators 301 in the stator group 300 comprising three stators 301 respectively.
So, when M is an odd number such as 3, 5, 7, 9, . . . , the connection method in the above embodiment can also be used.
As shown in
The above embodiments are merely preferred ones of the invention, and it should be pointed out that the above preferred embodiments should not be construed as limitations of the invention and the protection scope of the invention should be defined by the claims. Those ordinarily skilled in the art can make some improvements and modifications without departing from the spirit and scope of the invention, and all these improvements and modifications should also fall within the protection scope of the invention.
Number | Date | Country | Kind |
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202110783181.X | Jul 2021 | CN | national |
This application is the national phase entry of International Application No. PCT/CN2022/103547, filed on Jul. 4, 2022, which is based upon and claims priority to Chinese Patent Application No. 202110783181.X, filed on Jul. 12, 2021, the entire contents of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/CN2022/103547 | 7/4/2022 | WO |