CN113380490A

CN113380490A - Superconducting switch for superconducting magnet system of superconducting maglev train

Info

Publication number: CN113380490A
Application number: CN202110497160.1A
Authority: CN
Inventors: 郑金星; 邹春龙; 刘旭峰; 奚维斌; 刘菲; 李明
Original assignee: Hefei Institutes of Physical Science of CAS
Current assignee: Hefei Institutes of Physical Science of CAS
Priority date: 2021-05-07
Filing date: 2021-05-07
Publication date: 2021-09-10

Abstract

The invention provides a superconducting switch for a superconducting magnet system of a superconducting maglev train, which comprises a magnesium oxide substrate, wherein the superconducting switch is of a film structure, a superconducting tape YBCO film is plated on the front end surface of the magnesium oxide substrate, the superconducting tape YBCO film is designed into a snake-shaped routing with a gap on the front end surface of the magnesium oxide substrate, a layer of gold foil is plated on the superconducting tape YBCO film positioned at the upper end and the lower end of the magnesium oxide substrate, and a heating wire of the snake-shaped routing is wound on the rear end surface of the magnesium oxide substrate. The superconducting switch can realize the closed-loop operation of the superconducting coil, realize a long-time high-stability noiseless magnetic field, eliminate a vehicle-mounted power supply for coil excitation, reduce the weight of a maglev train, and can be used in parallel with a low-temperature diode in use, thereby realizing the effective safety protection of the superconducting switch and reducing the damage rate of the superconducting switch.

Description

Superconducting switch for superconducting magnet system of superconducting maglev train

Technical Field

The invention relates to the technical field of electromagnetic systems, in particular to a superconducting switch for a superconducting magnet system of a superconducting maglev train.

Background

The superconducting phenomenon is discovered since 1911, and is widely applied to the electromagnetic field due to the excellent characteristics of zero resistance and the like, but the application occasions of the superconductor are greatly limited due to the lower critical temperature of the superconductor; with the discovery of more and more high-critical-temperature superconducting materials, particularly the discovery of a second high-temperature superconducting material ReBCO, the low-temperature environment of superconducting application is greatly reduced, the application range of superconducting is promoted, and the second high-temperature superconducting material completely has the basis of commercial application. The demand for traffic speed and comfort between cities is higher and higher, and a maglev train is one of the mainstream directions of the development of the new generation of high-speed rail transit as the representative of the high-tech rail transit.

In the magnetic suspension train, the suspension and the guidance of the train are realized through the mutual electromagnetic action between electromagnets on a track and a train body, so the electromagnets are core components of a train suspension system and a propulsion system. The traditional electromagnet is mainly electrified through an aluminum electromagnetic coil to generate electromagnetic force, so that the purpose of suspension and propulsion of a train is achieved, but the economic operation cost of the magnetic suspension train is high due to the fact that the traditional electromagnet is heavy in weight and high in energy consumption. Under the condition that the size and the number of turns of the coil are the same, the larger the current passed by the coil is, the stronger the magnetic field generated by the magnet is, so that when the sections of the conductors are the same, the high-temperature superconducting coil can bear dozens of times of current higher than the aluminum coil, namely, a stronger magnetic field is generated; meanwhile, the aluminum coil can continuously generate Joule loss when being electrified, and the superconducting coil can not generate Joule loss because of no resistance, so that compared with a conventional magnet, the high-temperature superconducting magnet has the characteristics of more compact structure, lower weight, less energy consumption and the like under the same suspension and driving force requirements. The high-temperature superconducting magnet system is applied to the magnetic levitation train, so that the running cost of the train can be reduced, the running stability of the train can be improved, and the passenger capacity of the train can be improved.

Therefore, a superconducting magnet system for a superconducting maglev train is developed, the requirements of the maglev train on suspension and propulsion are met, the power supply problem of the superconducting magnet and a low-temperature system in the operation is solved, the superconducting magnet and the low-temperature system meet various complex service working conditions of the maglev train in operation, technical support is provided for the design of the suspension and propulsion system of the maglev train, namely, the used superconducting magnet needs to realize closed-loop operation in the operation process and is disconnected with an external power supply, and therefore, a special superconducting switch is designed for cutting off a coil and an external power supply system after the excitation of the coil is completed, and the coil is ensured to be in a closed-loop operation environment.

Disclosure of Invention

The invention aims to provide a superconducting switch for a superconducting magnet system of a superconducting maglev train, which aims to overcome the defects in the prior art, meet various complex service working conditions of the operation of the maglev train, reduce the operation cost of the train, improve the operation stability of the train and solve the problem of power supply of the conventional superconducting magnet and a low-temperature system in the operation. In order to achieve the purpose, the invention is realized by the following technical scheme:

a superconducting switch for a superconducting magnet system of a superconducting maglev train comprises a magnesium oxide base body and is characterized in that the superconducting switch is of a film type structure, a superconducting tape YBCO film is plated on the front end face of the magnesium oxide base body, the superconducting tape YBCO film is designed into a gapped snake-shaped wire on the front end face of the magnesium oxide base body, a layer of gold foil is plated on the superconducting tape YBCO film positioned at the upper end and the lower end of the magnesium oxide base body, and a heating wire of the snake-shaped wire is wound on the rear end face of the magnesium oxide base body.

Preferably, the thickness of the superconducting tape YBCO film is 300 nm.

Preferably, the gold foil has a thickness of 1-5 um.

Preferably, the heating wire can be selected from an iron chromium aluminum heating wire or a nickel chromium heating wire.

Preferably, the diameter of the heating wire is not less than 3mm, and the thickness of the flat belt is not less than 2 mm.

The invention has the beneficial effects that:

the superconducting switch for the superconducting magnet system of the superconducting maglev train can disconnect the coil from the excitation power supply after the superconducting coil completes excitation, thereby realizing the closed-loop operation of the superconducting coil and realizing a long-time high-stability noiseless magnetic field; the magnet can maintain stable exciting current for a long time by one-time power supply, avoids the excitation input of a continuous power supply in the running process, can cancel a coil-excited vehicle-mounted power supply, further reduces the weight of the magnetic suspension train, and improves the running efficiency of the system. When the superconducting switch is used, the use mode of parallel connection with the low-temperature diode is adopted, and when the magnet loses time, the voltage at two ends of the diode can be increased to conduct the diode, so that the shunting effect is generated on the superconducting switch, and the effective protection on the superconducting switch is realized; the superconducting switch is used in parallel with the low-temperature diode, so that the superconducting switch can be effectively and safely protected, and the damage rate of the superconducting switch is reduced.

Drawings

FIG. 1 is a schematic front view of a superconducting switch according to the present invention;

FIG. 2 is a schematic diagram of a back side structure of the superconducting switch of the present invention;

fig. 3 is a schematic diagram of an implementation circuit of the superconducting switch of the present invention.

In the figure: 1. a magnesium oxide matrix; 2. a superconducting tape YBCO film; 3. gold foil; 4. a heating wire.

Detailed Description

The invention will be further described with reference to the accompanying drawings and the detailed description below:

example 1:

as shown in fig. 1 to 2, a superconducting switch for a superconducting magnet system of a superconducting maglev train comprises a magnesium oxide substrate 1, the superconducting switch of the present invention is preferably of a film structure, that is, a superconducting tape YBCO film 2 with a high-temperature superconducting function is plated on the front end surface of the magnesium oxide substrate 1 with a good heat conducting property, and the film plating mode not only can enhance the mechanical strength of the high-temperature superconducting film, but also can realize the rapid temperature transfer when a back heating wire 4 is heated, thereby completing the function realization of opening and closing the superconducting switch; the thickness of the superconducting tape YBCO film 2 is preferably 300nm, and the superconducting tape YBCO film 2 needs to be designed into a gapped planar circuit snake-shaped wire on the front end surface of the magnesium oxide substrate 1, and the snake-shaped wire can save space and increase the line length, so that the resistance value of the superconducting tape YBCO film 2 in a non-superconducting state is increased, and the current rising rate and the current falling rate of a coil are further improved; still plate one deck gold foil 3 again on the superconductive tape YBCO film 2 that is located magnesium oxide base member 1 upper and lower both ends, be convenient for with the YBCO tape connection, the thickness of gold foil 3 sets up to between 1-5um, and still twine the heater strip 4 of snakelike line at the rear end face of magnesium oxide base member 1, through the disconnection of heater strip 4 control superconductive switch, heater strip 4 can select for indisputable chromium aluminium heating wire or nickel chromium heating wire, and the diameter of heater strip 4 is not less than 3mm, and the bandlet thickness is not less than 2 mm.

The working principle and the working process of the superconducting switch are as follows:

as shown in fig. 3, the superconducting switch, the diode assembly and the superconducting coil are connected in parallel, the three are connected with a magnet power supply through a power supply lead, and the back heating wire 4 of the superconducting switch is separately connected with the power supply.

The superconducting coil, the superconducting section of the connecting wire and the superconducting switch are arranged in a low-temperature-zone cooling environment to ensure that the superconducting tape YBCO film 2 enters a superconducting state, then a power supply is turned on, the magnesium oxide matrix 1 is heated by the heating wire 4, and heat can be transmitted to the superconducting tape YBCO film 2 through the magnesium oxide matrix 1, so that the superconducting tape YBCO film 2 is converted into a non-superconducting state from the superconducting state; then, a power supply lead is used for exciting the superconducting magnet, the superconducting switch and the superconducting coil are in a parallel connection structure, and the current only forms a closed loop among the power supply, the current lead and the superconducting coil because the superconducting switch is in a non-superconducting state and is resistive at the moment; according to the set current rate, the magnet power supply energizes the superconducting coils until the coil current reaches a set value, i.e., a saturated state.

After the superconducting coil excitation is finished (namely the superconducting coil reaches a saturated state), the heating power supply is closed, the superconducting switch is gradually cooled and returns to a superconducting state along with the stop of the heating wire 4, at the moment, the resistance of the superconducting section is far smaller than the resistance of a current lead between the magnet power supply and the superconducting coil, the superconducting coil is used as an inductive element, a new closed loop is formed between the superconducting coil and the superconducting switch, a loop is not formed between the magnet power supply and a power supply lead, at the moment, the whole circuit is an internal closed circuit, the resistance value between the superconducting coil and the superconducting joint is small, the electric loss of the joint is low, the current attenuation in the whole superconducting closed loop is very small, and therefore the superconducting coil can generate a continuous magnetic field within a certain time. When the current in the superconducting coil decays to a critical value, the operation can be repeated, and the coil is excited and charged again.

Various other modifications and changes may be made by those skilled in the art based on the above-described technical solutions and concepts, and all such modifications and changes should fall within the scope of the claims of the present invention.

Claims

1. A superconducting switch for a superconducting magnet system of a superconducting maglev train comprises a magnesium oxide base body and is characterized in that the superconducting switch is of a film type structure, a superconducting tape YBCO film is plated on the front end face of the magnesium oxide base body, the superconducting tape YBCO film is designed into a gapped snake-shaped wire on the front end face of the magnesium oxide base body, a layer of gold foil is plated on the superconducting tape YBCO film positioned at the upper end and the lower end of the magnesium oxide base body, and a heating wire of the snake-shaped wire is wound on the rear end face of the magnesium oxide base body.

2. The superconducting switch for a superconducting magnet system of a superconducting maglev train according to claim 1, wherein the thickness of the superconducting tape YBCO thin film is 300 nm.

3. A superconducting switch for a superconducting magnet system of a superconducting magnetic levitation train as claimed in claim 1, wherein the gold foil has a thickness of 1-5 um.

4. A superconducting switch for a superconducting magnet system of a superconducting maglev train according to claim 1, wherein the heating wire is selected from an iron chromium aluminum heating wire or a nickel chromium heating wire.

5. A superconducting switch for a superconducting magnet system of a superconducting maglev train according to claim 4, wherein the diameter of the heating wire is not less than 3mm and the ribbon thickness is not less than 2 mm.