Superconducting uninsulated magnet quick charging structure and charging method

Abstract

The invention discloses a superconductive uninsulated magnet rapid charging structure and a charging method, and relates to the technical field of superconductive magnet charging, a mutual inductance coil is arranged in a superconductive magnet and is electrified, induction current is generated in the superconductive magnet by using a mutual inductance phenomenon, and the charging speed of the superconductive magnet is improved; the mutual inductance coefficient between the mutual inductance coil and the superconducting magnet is a negative value; according to the charging method of the rapid charging structure for the superconducting uninsulated magnet, the mutual inductance coil is arranged and electrified, induced current is generated in the superconducting magnet by utilizing a mutual inductance phenomenon, and the charging speed of the superconducting magnet is increased; the basic principle is that the induced magnetic field of the superconducting magnet is counteracted by utilizing the induced magnetic field of the mutual induction coil, so that the induced electromotive force of the superconducting magnet is reduced, the obstruction to the current is reduced, and the charging speed is finally improved.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting magnet charging, in particular to a superconducting non-insulated magnet fast charging structure and a charging method. Background Art

[0002] Superconducting magnets have many applications in the fields of medicine, magnetic levitation, high-energy physics, etc. Uninsulated magnets have strong overcurrent carrying capacity and can generate strong magnetic fields. Compared with superconducting magnets with insulation layers, uninsulated magnets have charging delays due to the presence of interturn resistance. In the equivalent circuit model of uninsulated superconducting magnets, the inductance and interturn resistance are in parallel. At the beginning of charging, when the reverse electromotive force of the inductor is generated, the charging current is shunted to the interturn resistance branch, resulting in charging delays. For large non-insulated magnets with large inductance, the charging time will reach tens of minutes to hours, and the magnet will also generate AC losses during the charging process.

[0003] At present, the methods to improve the charging speed include intelligent non-insulated magnet design, adding metal insulation, increasing power supply power and multi-strip co-winding. Intelligent non-insulated magnets take advantage of the special change of resistivity of V2O3 under the action of temperature: when the temperature is below 175K, it behaves as an insulating material. When the temperature rises to 175K, the resistance decreases rapidly, showing conductive properties; through the change of resistance with temperature, high-temperature superconducting magnets behave as insulating magnets at low temperatures, and behave as non-insulated magnets when the temperature is above 175K. Adding a metal insulation layer will increase the inter-turn resistance, thereby reducing the time constant. The way to increase the power supply power is limited by the actual application power supply power and cannot be increased infinitely. Multi-strip co-winding actually reduces the inductance of the magnet, thereby increasing the charging speed. These methods are only applicable to the design stage and have little effect on improving the charging speed of existing magnets and further improvements. Summary of the invention

[0004] The object of the present invention is to provide a superconducting non-insulated magnet fast charging structure and charging method to solve the problem that the prior art proposed in the above background technology cannot further improve the charging speed of the existing magnet.

[0005] To achieve the above object, the present invention provides the following technical solutions: The invention discloses a fast charging structure for a superconducting non-insulated magnet, comprising a superconducting magnet and a mutual inductance coil arranged inside the superconducting magnet.

[0006] Furthermore, the superconducting magnet is configured to be D-shaped, and the mutual inductance coil is circular and is disposed close to a straight edge of the D-shaped superconducting magnet.

[0007] Furthermore, the access circuit of the mutual inductance coil is connected in series with the connection circuit of the superconducting magnet, and a switching switch is installed on the access circuit of the mutual inductance coil, and the connection or disconnection between the access circuit of the mutual inductance coil and the connection circuit of the superconducting magnet is achieved through the switching operation of the switching switch.

[0008] Furthermore, a diode and a fixed resistor are connected in parallel to the access circuit of the mutual inductance coil.

[0009] Furthermore, the mutual inductance coil is a multi-turn superconducting coil with insulation, and the superconducting magnet is a hollow non-insulated superconducting coil with an inner diameter sufficient to accommodate the mutual inductance coil.

[0010] The present invention also provides a method for fast charging of a superconducting non-insulated magnet, which increases the charging speed of the superconducting magnet by energizing the mutual inductance coil and utilizing the mutual inductance phenomenon to generate an induced current in the superconducting magnet.

[0011] As a further solution of the present invention: by winding the mutual inductance coil and the coil of the superconducting magnet in opposite directions, the mutual inductance coefficient between the mutual inductance coil and the superconducting magnet is made to be negative, thereby offsetting the induced magnetic field of the superconducting magnet, reducing the induced electromotive force of the superconducting magnet, reducing the resistance to the current, and improving the charging speed of the superconducting magnet; negative mutual inductance means that the magnetic flux directions of the two coils are opposite, that is, the magnetic field generated by one coil weakens the magnetic flux of the other coil.

[0012] As a further solution of the present invention: by constructing an analytical formula for the correlation between the superconducting magnet charging current, charging speed and mutual inductance, it is convenient to substitute data for direct solution and calculation; the superconducting magnet charging current I L1 The analytical formula is:

[0013]

[0014]

[0015]

[0016] Among them, A is the charging speed of the current source, t represents time, t0 is the time when the power supply current reaches the maximum value, I0 is the inductor current when the power supply current reaches the maximum value, the inductor current refers to the current in the equivalent inductance branch of the non-insulated magnet, which can be regarded as the actual current of the magnet, the time constant τ is applied in the dynamic system, reflecting the progress speed of the transition process of the dynamic system. In the first-order dynamic circuit, it represents the speed of the charging or discharging process of the capacitor or inductor; e is a natural constant; L1 is the inductance of the superconducting magnet, R1 is the equivalent radial turn-to-turn resistance of the superconducting magnet, M is the mutual inductance coefficient between the mutual inductance coil and the superconducting magnet, and Iop represents the power supply current, and Ip refers to the peak value of Iop; As a further solution of the present invention: by increasing the number of turns of the mutual inductance coil, the mutual inductance coefficient is increased, and the charging speed of the superconducting magnet is increased.

[0017] As a further solution of the present invention: the charging speed of the superconducting magnet is increased by increasing the surrounding area of ​​the mutual inductance coil.

[0018] As a further solution of the present invention: the superconducting magnet and the mutual inductance coil are both immersed in liquid nitrogen in the Dewar container.

[0019] As a further solution of the present invention: by connecting the superconducting magnet and the mutual inductance coil in series, the mutual inductance coil will not shunt the power supply current, thereby improving the charging efficiency.

[0020] As a further solution of the present invention, a switching switch is installed on the access circuit of the mutual inductance coil, and the current of the access circuit of the mutual inductance coil and the connection circuit of the superconducting magnet is disconnected after charging is completed, so as not to affect the subsequent operation of the superconducting magnet.

[0021] As a further solution of the present invention: by installing a diode on the connecting circuit of the mutual inductance coil, the conduction direction of the diode is consistent with the current direction of the connecting circuit, which helps to reduce the current of the mutual inductance coil, thereby facilitating the switching operation of the switching switch and reducing the influence of the mutual inductance coil on the superconducting magnet when the switching switch is switching.

[0022] As a further solution of the present invention: the superconducting magnet of the present application is made of V2O3 material; and the superconducting magnet is wound with multiple strips.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: the superconducting non-insulated magnet fast charging method of the present invention, by setting a mutual inductance coil and energizing it, utilizes the mutual inductance phenomenon to generate an induced current in the superconducting magnet, thereby improving the charging speed of the superconducting magnet; its basic principle is to utilize the induced magnetic field of the mutual inductance coil to offset the induced magnetic field of the superconducting magnet, thereby reducing the induced electromotive force of the superconducting magnet, reducing the obstacle to the current, and finally achieving the improvement of the charging speed; therefore, the mutual inductance coil of the present application is wound in the opposite direction to the coil of the superconducting magnet, that is, the mutual inductance coefficient is negative, thereby achieving the weakening of the induced electromotive force of the superconducting magnet; In order to increase the mutual inductance coefficient between the mutual inductance coil and the superconducting magnet and speed up the charging speed of the superconducting magnet, the present invention further improves the number of coil turns, the relative position of the coil, the winding direction of the coil, etc. As for the relative position of the coils, the present application arranges the mutual inductance coil inside the coil of the superconducting magnet, so as to reduce the distance between the two coils, so that the magnetic field coupling between the coil of the superconducting magnet and the mutual inductance coil is enhanced, resulting in an increase in the mutual inductance coefficient; as for the winding direction of the coil, the mutual inductance coil of the present application is opposite to the winding direction of the coil of the superconducting magnet, that is, the mutual inductance coefficient is negative, thereby achieving the weakening of the induced electromotive force of the superconducting magnet and accelerating the charging speed of the superconducting magnet; further through multiple groups of tests, the influence of the number of coil turns and the inner diameter of the coil on the effect of the fast charging method of the present invention is clarified to facilitate practical application.

[0024] The circuit structure provided by the present invention connects the superconducting magnet and the circuit where the mutual inductance coil is located in series, so that the mutual inductance coil does not shunt the power supply current, thereby improving the charging efficiency; at the same time, the series connection allows the superconducting magnet and the mutual inductance coil to share a power supply, reducing equipment requirements, and uses the unidirectional conduction performance of the diode to block the mutual inductance current, thereby reducing the current of the mutual inductance coil, which is beneficial to the switching operation of the switching switch and reduces the influence of the mutual inductance coil on the superconducting magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the position layout of the superconducting magnet and the mutual inductance coil of the present invention; Figure 2 is an equivalent circuit diagram of the circuit structure of the present invention; Figure 3 It is a schematic diagram of the working state change of the equivalent circuit of the present invention; Figure 4 This is a graph showing the influence of the number of turns of the superconducting magnet on the mutual inductance and charging time of the present invention; Figure 5 This is a graph showing the effect of the number of turns of the mutual inductance coil on the charging time; Figure 6 This is a graph showing the effect of the inner diameter of the mutual inductance coil on the charging time of the present invention; Figure 7 It is a schematic diagram of the layout of the circuit device of the present invention.

[0026] In the figure: 1. Superconducting magnet; 2. Mutual inductance coil. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] See also Figure 1 , Figure 1 This is a schematic diagram of the position layout of the superconducting magnet 1 and the mutual inductance coil 2 used for the superconducting magnet 1 fast charging method in the embodiment of the present application. The principle structure of the superconducting non-insulated magnet fast charging method includes a superconducting magnet 1 and a mutual inductance coil 2, wherein the mutual inductance coil 2 is insulated, and the mutual inductance coil 2 is a tightly wound multi-turn circular coil of the superconducting magnet 1 with insulation, and the superconducting magnet 1 is a hollow non-insulated superconducting magnet 1 coil with an inner diameter sufficient to accommodate the mutual inductance coil 2. Referring to the existing mature technology that can improve the charging speed of the superconducting magnet 1, this application makes the following settings: The superconducting magnet 1 of the present application adopts multiple tapes to be wound together, so as to improve the current density: superconducting materials have the ability to maintain a superconducting state under high current density. By adopting the method of multiple tapes to be wound together, more superconducting materials can be integrated into the magnet structure, thereby improving the overall current carrying capacity without increasing the volume and weight of the magnet; it is helpful to generate a stronger magnetic field in the superconducting magnet 1; At the same time, the co-winding of multiple strips can make the magnetic field distribution of the superconducting magnet 1 more uniform. During the winding process, by accurately controlling the arrangement and winding method of each strip, the strength and direction of the magnetic field can achieve the required uniformity at different positions. The superconducting magnet 1 needs to withstand large electromagnetic forces and thermal stresses during operation. The co-winding of multiple strips can make the structure of the magnet more solid and improve mechanical stability. At the same time, the interaction between multiple strips also helps to disperse and balance stress, reducing the risk of damage to the magnet due to uneven force.

[0029] When the superconducting magnet 1 is running in the superconducting state, the resistance is zero, so no Joule heat loss is generated. By adopting the method of multiple tapes co-winding, the efficiency of the magnet can be further improved, the energy consumption can be reduced, and the superconducting magnet 1 can be operated stably for a long time while maintaining the superconducting state. By adopting the method of multiple tapes co-winding, the winding method and arrangement method of the magnet can be flexibly designed, thereby producing a superconducting magnet 1 with a complex magnetic field configuration.

[0030] The method for fast charging a superconducting non-insulated magnet of the present invention places a mutual inductance coil 2 inside a superconducting magnet 1 and energizes it, thereby utilizing the mutual inductance phenomenon to generate an induced current in the superconducting magnet 1, thereby increasing the charging speed of the superconducting magnet 1; the mutual inductance coefficient between the mutual inductance coil 2 and the superconducting magnet 1 is a negative value, and negative mutual inductance indicates that the magnetic flux directions of the two coils are opposite, that is, the magnetic field generated by one coil weakens the magnetic field of the other coil.

[0031] The present invention does not limit the shape and size of the superconducting magnet 1 and the mutual inductance coil 2. Figure 1 The structures shown are for illustrative purposes only.

[0032] The working process of the fast charging method of the present application is described below: See also Figure 2 and Figure 3 , Figure 2 An equivalent circuit of the circuit structure for realizing the method for fast charging of superconducting non-insulated magnets of the present application; Figure 3 It includes the overall circuit (a), the circuit status diagram at the beginning of charging (b), and the circuit status diagram at the end of charging (c). The power supply supplies power to the mutual inductance coil 2 and the superconducting magnet 1. In the diagram, L1 is the inductance of the superconducting magnet 1, and R1 is the equivalent radial inter-turn resistance of the superconducting magnet 1, that is, the resistance of the current path composed of the metal layer and the gap between the strips wound around the superconducting magnet 1. When the current of the superconducting magnet 1 is stable, the current will not flow through the turns. Only when the current changes will the current flow through the turns; L2 is the inductance of the mutual inductance coil 2.

[0033] After the circuit structure is connected, the shape is as described in the overall circuit (a), including two parts, one part is the connected circuit where the superconducting magnet 1 is located, which is equivalent to the radial resistance R1 and the inductance L1; the other part is the access circuit where the mutual inductance coil 2 is located, on which a fixed value resistor R2 and a diode are arranged; the fixed value resistor R2 cooperates with the diode to release the energy added on the mutual inductance coil 2, which helps to reduce the current of the mutual inductance coil 2, thereby facilitating the switching switch from position 1 (i.e. Figure 2 Switch from position ① in the middle to position 2 (i.e. Figure 2 ② in the figure), thereby disconnecting the circuit where the mutual inductance coil 2 is located. After the superconducting magnet 1 is charged, the switch S is switched to position 2. During the process of the mutual inductance coil releasing energy through the fixed resistor R2, the influence of the mutual inductance coil 2 on the superconducting magnet 1 is reduced.

[0034] At this time, the superconducting magnet 1 is connected to the power supply device through the circuit, and the working state of the superconducting magnet 1 and the circuit in which it is located is controlled by the opening and closing of the power supply device itself and the change of the output current; one end of the circuit in which the mutual inductance coil 2 is located is connected to the power supply device, and the other end is connected to position one of the switching switch. At this time, the switching switch is in position one, so that the circuit in which the mutual inductance coil 2 is located is connected to the power supply device.

[0035] After the circuit of the mutual inductance coil 2 is connected, it enters the charging process. First, the impedance of the mutual inductance coil 2 itself will delay the increase of the current. Then, when the current of the mutual inductance coil 2 reaches the maximum and remains stable (the maximum current that the mutual inductance coil 2 can withstand is less than the maximum current of the superconducting magnet 1, so it can enter the stable state quickly), the state of the circuit at this time is as follows: Figure 3 As shown in (b), only the inductance of the mutual inductance coil 2 is considered; After the superconducting magnet 1 is charged, the switch is switched from position 1 to position 2. Figure 3 As shown in (c), at this time, the circuit where the mutual inductance coil 2 is located is disconnected from the circuit where the superconducting magnet 1 is located. That is, the switching switch is set to remove the circuit where the mutual inductance coil 2 is located after charging is completed, so as not to affect the subsequent work of the non-insulated magnet.

[0036] According to circuit theory and Laplace transform law, Figure 3 The analytical formula for the charging current of the superconducting magnet 1 is derived as follows: Based on circuit theory and Laplace transform law, Figure 3 The complex frequency domain analytical formula of the coil charging current of the non-insulated superconducting magnet 1 in (b) is:

[0037]

[0038] The solution to the above complex frequency domain equation is:

[0039]

[0040] By Laplace inversion:

[0041]

[0042] Charging speed:

[0043] After the current source reaches the peak value Ip, Figure 3 The complex frequency domain analytical formula of the charging current in (b) is:

[0044]

[0045]

[0046] By Laplace inversion:

[0047]

[0048] Charging speed:

[0049] To sum up the above, according to circuit theory and Laplace transform law, Figure 3 The analytical formula for the charging current of the superconducting magnet 1 is:

[0050]

[0051]

[0052]

[0053] Among them, A is the charging speed of the current source, t represents time, t0 is the time when the power supply current reaches the maximum value, I0 is the inductor current when the power supply current reaches the maximum value, the inductor current refers to the current in the equivalent inductance branch of the non-insulated magnet, which can be regarded as the actual current of the magnet, the time constant τ is applied in the dynamic system, reflecting the progress speed of the transition process of the dynamic system, in the first-order dynamic circuit, it represents the speed of the charging or discharging process of the capacitor or inductor; e is a natural constant; s represents the complex frequency, which is used to describe the frequency characteristics in the circuit; L1 is the inductance of the superconducting magnet 1, R1 is the equivalent radial turn-to-turn resistance of the superconducting magnet 1, M is the mutual inductance coefficient between the mutual inductance coil 2 and the superconducting magnet 1, and Iop represents the power supply current, and Ip refers to the peak value of Iop; by constructing the correlation analytical formula of the charging current, charging speed and mutual inductance coefficient of the superconducting magnet 1, it is convenient to substitute the data for solution and calculation, and obtain tables and data diagrams; Under the premise that the power of the power source and the material and design of the superconducting magnet 1 itself have been determined, the charging speed of the superconducting magnet 1 can be affected by the mutual inductance coefficient between the superconducting magnet 1 and the mutual inductance coil 2; Common factors that can affect the mutual inductance coefficient between the superconducting magnet 1 and the mutual inductance coil 2 include: the number of coil turns, the relative position of the coils, the winding direction of the coils, the geometric shape and size of the coils, etc. For the relative position of the coils, see Figure 1-2, the present application sets the mutual inductance coil 2 inside the coil of the superconducting magnet 1, so as to reduce the distance between the two coils, so that the magnetic field coupling between the coil of the superconducting magnet 1 and the mutual inductance coil 2 is enhanced, resulting in an increase in the mutual inductance coefficient; as for the winding direction of the coil, the basic principle of the present application is to use the induced magnetic field of the mutual inductance coil 2 to offset the induced magnetic field of the superconducting magnet 1, thereby reducing the induced electromotive force of the superconducting magnet 1, reducing the obstruction to the current, and finally achieving an increase in the charging speed. Therefore, the mutual inductance coil 2 of the present application is opposite to the winding direction of the coil of the superconducting magnet 1, that is, the mutual inductance coefficient M is negative, thereby achieving the weakening of the induced electromotive force of the superconducting magnet 1; As for the coil geometry, the coil of the superconducting magnet 1 of this embodiment is D-shaped, and the mutual inductance coil 2 is circular and is arranged inside the coil of the superconducting magnet 1 near the straight edge. The magnetic field distribution of the D-shaped coil has a certain directionality. When the current passes through the D-shaped coil, the magnetic field is mainly concentrated near the straight edge, forming a relatively strong magnetic field area. By arranging the mutual inductance coil 2 in the area close to the straight edge, a stronger mutual inductance coefficient can be obtained; in this embodiment, the coil of the superconducting magnet 1 is divided into a straight edge and a circular edge, and the radius of the circular edge is called the large circle radius, represented by r1; the transition section between the straight edge and the circular edge is set to a quarter-circle arc, and the radius of the arc is called the small circle radius, represented by r2; then the actual length of the straight edge should be twice r1 minus the radius r2 of the two arcs, that is, 2 (r1-r2).

[0054] Therefore, this embodiment mainly describes the effect of the charging method of the present application by changing the number of turns of the superconducting magnet 1 and the mutual inductance coil 2, as well as the inner diameter of the mutual inductance coil 2. The specific embodiments, experimental data and analysis are as follows: In this embodiment, original structural parameters of the superconducting magnet 1 and the mutual inductance coil 2 are shown in Table 1.

[0055] Table 1 Main structural parameters of superconducting magnet 1 and mutual inductance coil 2

[0056] The circuit is constructed based on the structural parameters in Table 1. Under the condition that the charging speed of the current source is 2A / s, the charging process of the 4-turn superconducting magnet 1 coil and the 20-turn superconducting magnet 1 coil is as follows: Figure 3 As shown; see Table 2 for specific parameters: Table 2 Effect of the number of turns of the coil of superconducting magnet 1 on the mutual inductance and charging time

[0057] In the above Table 2, the input current speed is 2A per second, and the mutual inductance coefficient is 0, indicating that the mutual inductance coil 2 is not connected; From the comparison between the first and third rows in Table 2, it can be seen that when the number of turns of the superconducting magnet 1 coil is increased from 4 to 20 without the mutual inductance coil 2, the charging time increases from 355 seconds to 464 seconds; that is, the increase in the number of turns of the superconducting magnet 1 coil itself leads to an increase in inductance, which will extend the charging time. From the comparison between the second row and the fourth row in Table 2, it can be seen that when the number of turns of the superconducting magnet 1 coil changes from 4 turns to 20 turns when the mutual inductance coil 2 is connected, the mutual inductance coefficient will be enhanced, and the charging time will be extended from 336 seconds to 455 seconds. From the comparison between the first and second rows in Table 2, it can be seen that when the number of turns of the superconducting magnet 1 coil is 4, after the mutual inductance coil 2 is connected, the charging time is reduced from 355 seconds to 336 seconds, and the charging time accelerated by the mutual inductance coil is 9 seconds; From the comparison between the third and fourth rows in Table 2, it can be seen that when the number of turns of the superconducting magnet 1 coil is 20, after the mutual inductance coil 2 is connected, the charging time is reduced from 464 seconds to 455 seconds, and the charging time accelerated by the mutual inductance coil is 19 seconds; In summary, Figure 4 , combined with the data in Table 2, the conclusion can be drawn that: the more turns the superconducting magnet 1 coil has, the stronger its own inductance L1 value is, which prolongs the charging time; and connecting the mutual inductance coil 2 can reduce the charging time. The more turns the superconducting magnet 1 coil has, the greater the mutual inductance coefficient M will be, but the mutual inductance coefficient changes very little relative to L1, which reduces M / L1, thereby reducing the acceleration effect. The circuit is constructed according to the structural parameters in Table 1 (the number of turns of the mutual inductance coil 2 is changed). Under the condition that the charging speed of the current source is 2A / s and the superconducting magnet 1 has 4 turns, the accelerated charging effect of the mutual inductance coil 2 with different turns on the 4 turns of the superconducting magnet 1 is as follows: Figure 3 (b) As shown; the specific parameters are shown in Table 3: Table 3 Effect of the number of turns of the mutual inductance coil on the charging time

[0058] In the test, the maximum current of superconducting magnet 1 is set to 200A. When the input current speed is 2A / s, Figure 4-6 The horizontal section after the maximum current reaches 200A represents the stage after the mutual inductance between the mutual inductance coil 2 and the superconducting magnet 1 completely compensates or even over-compensates the inductance of the superconducting magnet 1. It can be seen from Table 3 that when the charging speed of the current source is 2A / s and the superconducting magnet 1 has 4 turns of coil, as the number of turns of the mutual inductance coil 2 gradually increases, the charging time of the superconducting magnet 1 gradually decreases. When the number of turns of the mutual inductance coil 2 is 90, the charging time is 97 seconds, which is less than the charging time of the superconducting magnet 1 in the ideal state without the mutual inductance coil 2. In summary, Figure 5The conclusion drawn from the data in Table 3 is: increasing the number of turns of the mutual inductance coil 2 can reduce the charging time of the superconducting magnet 1; increasing the number of turns of the mutual inductance coil 2 can increase the mutual inductance coil 2 and the mutual inductance coefficient, thereby improving the charging speed of the superconducting magnet 1.

[0059] The circuit is constructed according to the structural parameters in Table 1 (the inner diameter of the mutual inductance coil 2 is changed). Under the condition of a current source charging speed of 2A / s and a 4-turn coil, the accelerated charging effect of the mutual inductance coil 2 with different inner diameters on the 4-turn superconducting magnet 1 is shown as follows: Figure 3 (c) as shown; the specific parameters are shown in Table 4: Table 4 Effect of the inner diameter of the mutual inductance coil on the charging time

[0060] Depend on Figure 6 Combined with Table 4, it can be seen that as the inner diameter of the mutual inductance coil 2 increases, the charging time decreases with the increase of the inner diameter of the mutual inductance coil 2. When the inner diameter of the mutual inductance coil 2 reaches 0.2m (the mutual inductance coil 2 of the present application is arranged inside the superconducting magnet 1, and the inner diameter of the coil of the superconducting magnet 1 adopted in the present application is 0.233m, so the 0.2m mutual inductance coil 2 basically reaches the maximum), the charging time is less than 100 seconds, that is, the charging speed exceeds the charging speed of the current source. That is, increasing the inner diameter of the mutual inductance coil 2, and then increasing the winding area of ​​the mutual inductance coil 2, can increase the mutual inductance coefficient between the mutual inductance coil 2 and the superconducting magnet 1, and then reduce the charging time of the superconducting magnet 1. In summary, by Figure 3 (c) The conclusion drawn from the data in Table 4 is that increasing the inner diameter of the mutual inductance coil 2 can reduce the charging time of the superconducting magnet 1.

[0061] The present invention also provides a charging structure for implementing the above-mentioned fast charging method; the charging structure comprises: The superconducting magnet 1 comprises a D-shaped or circular hollow non-insulated superconducting coil having an inner diameter sufficient to accommodate the mutual inductance coil 2; The mutual inductance coil 2 comprises a tightly wound multi-turn circular insulated superconducting coil; Electrical wiring, connecting the superconducting non-insulated coil and the mutual inductance coil 2 in series, and a switch device for controlling the access of the mutual inductance coil 2; by connecting the superconducting magnet 1 and the mutual inductance coil 2 in series, the mutual inductance coil 2 will not shunt the power supply current, thereby improving the charging efficiency; at the same time, the series connection allows the superconducting magnet 1 and the mutual inductance coil 2 to share a power supply, thereby reducing equipment requirements.

[0062] A switching switch is installed on the access circuit of the mutual inductance coil 2. The access circuit of the mutual inductance coil 2 is connected or disconnected with the circuit where the superconducting magnet 1 is located by switching the switching switch. After charging is completed, the connection current between the access circuit of the mutual inductance coil 2 and the superconducting magnet 1 is disconnected, thereby not affecting the subsequent work of the superconducting magnet 1.

[0063] When current passes through an inductor (i.e., a coil), a magnetic field is generated around it. This magnetic field is related to the magnitude and direction of the current. According to Faraday's law of electromagnetic induction, when the magnetic flux passing through a closed circuit changes, an induced electromotive force is generated in the circuit. In an inductor, when the current changes, the magnetic field around it will also change, thereby generating an induced electromotive force in the coil. The direction of this induced electromotive force is opposite to the direction of the current change, so it will hinder the change of the current. Therefore, when the switching switch disconnects the access circuit of the mutual inductance coil 2, the induced electromotive force of the mutual inductance coil 2 excites an induced current in the opposite direction of the input current. In order to avoid the induced current from affecting the charging operation of the superconducting magnet 1, a diode is installed on the circuit between the mutual inductance coil 2 and the switching switch. The conduction direction of the diode is consistent with the current direction. The unidirectional conduction performance of the diode is used to block the mutual inductance current, thereby reducing the current of the mutual inductance coil 2 during the switching process of the switching switch, which is beneficial to the switching operation of the switching switch and reduces the influence of the mutual inductance coil 2 on the superconducting magnet 1.

[0064] Furthermore, it also includes a Dewar container and a power supply device for maintaining the operation of the circuit structure, see Figure 7 The Dewar container is used to contain liquid nitrogen, in which the superconducting magnet 1 and the mutual inductance coil 2 are immersed; the power supply device is used to supply power to the superconducting magnet 1, and can provide a ramp current with a stable rate.

[0065] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A superconducting non-insulated magnet fast charging structure, characterized in that: It comprises a superconducting magnet (1) and a mutual inductance coil (2) arranged inside the superconducting magnet (1).

2. A superconducting non-insulated magnet fast charging structure according to claim 1, characterized in that: The superconducting magnet (1) is arranged in a D-shape, and the mutual inductance coil (2) is circular and arranged close to a straight edge of the D-shaped superconducting magnet (1).

3. A superconducting non-insulated magnet fast charging structure according to claim 1, characterized in that: The access circuit of the mutual inductance coil (2) is connected in series with the connection circuit of the superconducting magnet (1), and a switching switch is installed on the access circuit of the mutual inductance coil (2), and the connection or disconnection between the access circuit of the mutual inductance coil (2) and the connection circuit of the superconducting magnet (1) is achieved through the switching operation of the switching switch.

4. A superconducting non-insulated magnet fast charging structure according to claim 1, characterized in that: A diode and a fixed value resistor are connected in parallel to the access circuit of the mutual inductance coil (2).

5. A superconducting non-insulated magnet fast charging structure according to claim 1, characterized in that: The mutual induction coil (2) is a multi-turn superconducting coil with insulation, and the superconducting magnet (1) is a hollow non-insulated superconducting coil with an inner diameter sufficient to accommodate the mutual induction coil (2).

6. A charging method for a superconducting non-insulated magnet fast charging structure according to any one of claims 1 to 5, characterized in that: By energizing the mutual induction coil (2), an induced current is generated in the superconducting magnet (1) by utilizing the mutual induction phenomenon, so as to increase the charging speed of the superconducting magnet (1).

7. A charging method for a superconducting non-insulated magnet fast charging structure according to claim 6, characterized in that: By winding the mutual inductance coil (2) and the coil of the superconducting magnet (1) in opposite directions, the mutual inductance coefficient between the mutual inductance coil (2) and the superconducting magnet (1) is made negative, thereby offsetting the induced magnetic field of the superconducting magnet (1), reducing the induced electromotive force of the superconducting magnet (1), and reducing the resistance to the current, so as to increase the charging speed of the superconducting magnet (1).

8. The charging method of a superconducting non-insulated magnet fast charging structure according to claim 6, characterized in that: By increasing the number of turns of the mutual inductance coil (2), the mutual inductance coefficient is increased, thereby increasing the charging speed of the superconducting magnet (1); And / or, by increasing the surrounding area of ​​the mutual inductance coil (2), the charging speed of the superconducting magnet (1) is increased.

9. The charging method of a superconducting non-insulated magnet fast charging structure according to claim 6, characterized in that: By connecting the superconducting magnet (1) and the mutual inductance coil (2) in series, the mutual inductance coil (2) will not shunt the power supply current, thereby improving the charging efficiency.

10. The charging method of a superconducting non-insulated magnet fast charging structure according to claim 6, characterized in that: By installing a switching switch on the access circuit of the mutual inductance coil (2), the current of the access circuit of the mutual inductance coil (2) and the connection circuit of the superconducting magnet (1) is disconnected after charging is completed, thereby not affecting the subsequent operation of the superconducting magnet (1).

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