High-temperature superconducting joint welding device and heating method

Abstract

The invention discloses a high-temperature superconducting joint welding device and a heating method. The device comprises a superconducting joint, a high-frequency power supply, a water cooling system and a thermal imager, the superconducting joint is used for forming an alternating-current magnetic field; the high-frequency power supply is used for changing frequency and power of the superconducting joint; the water cooling system is used for cooling the superconducting joint and the high-frequency power supply; and the thermal imager is used for detecting temperature changes of the superconducting joint, the high-frequency power supply and the water cooling system in real time. The problems that in traditional welding, the heat conduction efficiency is low, the mechanical damage risk of contact type heating is high, rapid local heating cannot be achieved, and the over-temperature risk is caused due to no temperature feedback are solved, and the welding quality and reliability of the superconducting connector are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of superconducting joint welding technology, and more specifically to a high-temperature superconducting joint welding apparatus and heating method. Background Technology

[0002] High-temperature superconducting tapes are coated conductors produced using vacuum deposition technology and a multi-layer lamination and encapsulation method. They typically consist of a base layer, a buffer layer, a superconducting layer, a protective layer, and an encapsulation layer, and are widely used in superconducting magnets, power transmission, superconducting energy storage, and nuclear fusion. High-temperature superconducting tapes (such as...) Figure 1 As shown, YBCO (a typical non-metallic ceramic material) has the characteristics of high brittleness and poor heat resistance, and is easily damaged when welding current joints or splicing strips. Superconducting strips are narrow, thin and fragile, and are easily affected by external forces and high temperatures. However, their application often requires welding operations, for example: superconducting strips need to be welded to metal joints (4) / copper joints (called current joints) to carry current; due to production equipment limitations, multiple superconducting strips need to be welded end to end in series to form a longer strip; in the application of large superconducting magnets, the strips need to be wound on a metal skeleton that plays a supporting and current-carrying role, the skeleton and the superconductor contact to form an inner joint, and the outside forms an outer joint, and then multiple coils are stacked (in series) to form a magnet. Existing superconducting joint welding technology generally has the following problems: low thermal conductivity, traditional heating requires overall heating, high energy consumption and slow speed; physical contact easily causes mechanical damage to superconducting strips; lack of real-time temperature monitoring, which easily leads to local overheating and insufficient heating temperature accuracy; small temperature difference between the heating zone and the non-heating zone, and the non-welding area is significantly affected by heat.

[0003] Therefore, designing a non-contact high-frequency induction heating superconducting joint welding device is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the present invention provides a high-temperature superconducting joint welding device and heating method, which solves the problems of low thermal conductivity, high risk of mechanical damage from contact heating, inability to achieve rapid local heating and risk of overheating due to lack of temperature feedback in traditional welding, and significantly improves the welding quality and reliability of superconducting joints.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a high-temperature superconducting joint welding device, comprising: a superconducting joint, a high-frequency power supply, a water cooling system, and a thermal imager; Superconducting connectors are used to generate alternating magnetic fields; High-frequency power supplies are used to change the frequency and power of the superconducting connector; The water-cooling system is used to provide cooling for the superconducting connector and the high-frequency power supply; Thermal imagers are used to detect temperature changes in superconducting connectors, high-frequency power supplies, and water-cooling systems in real time.

[0006] Preferably, the superconducting joint comprises an induction coil and a welding tool, the welding tool is placed at the center of the induction coil, the high-frequency power supply applies high-frequency alternating current in the induction coil, and the welding tool is heated by the skin effect and eddy current effect.

[0007] Preferably, the welding tool comprises a superconducting tape, a solder, and a copper joint, and there is a uniform gap between the superconducting tape, the solder, and the copper joint.

[0008] Preferably, a heating method of a high-temperature superconducting joint welding device comprises the following steps: Initial preparation: after fixing the superconducting tape, the solder, and the copper joint to form a welding workpiece, the welding workpiece is placed in the induction coil, and the water cooling system and the thermal imager are started; Parameter setting: the key parameters of the high-frequency power supply are set in advance, including the working frequency, the output power, the heating time, and the preset temperature safety threshold; Heating control: the high-frequency power supply is started, and the thermal imager continuously scans the surface temperature distribution of the welding workpiece; Temperature judgment: the water cooling system judges whether the temperature of the welding workpiece reaches the preset threshold in real time, and stops heating when the preset value is reached, and a high-strength superconducting joint is formed after cooling.

[0009] Preferably, the heating control specifically comprises: the high-frequency power supply forms a preset alternating magnetic field in the induction coil; The welding tool is placed in the alternating magnetic field, and the welding tool forms an eddy current on the surface under the action of the alternating magnetic field, thereby heating the surface of the welding tool; The relative position of the welding tool and the induction coil and the frequency and power of the high-frequency power supply are continuously changed, the process of continuously changing the position, the frequency, and the power is discretized, the heating effect of the welding tool at each position is calculated and experimented, COMSOL simulation software is used to simulate electricity, magnetism, heat, and force for each specific working condition, and the optimal heating parameters are calculated, thereby guiding the actual experiment; then the deviation of the simulation is corrected through the heating effect of the actual experiment for verification and feedback, and finally the optimal heating effect data is obtained; The heating effect data is stored in a database; According to user needs, the optimal heating effect data is found from the database to heat the welding tool, and the optimal heating effect is obtained.

[0010] According to the above technical solution, compared with the prior art, the application provides a high-temperature superconducting joint welding device and a heating method, and has the following beneficial effects: Non-contact high-frequency induction heating: the eddy current effect is excited at the superconducting joint by the high-frequency alternating electromagnetic field, the local rapid heating (second level) of the heated workpiece is realized, and the superconducting joint and the heating device are truly not in contact; Infrared thermal imager temperature monitoring: real-time monitoring of welding tool temperature distribution, while feeding the temperature signal to the high-frequency power supply, realizing over-temperature stop, avoiding overheating damage to superconducting performance; Skin effect precise depth control: adjust the power heating frequency to control the heating depth and adjust the power to control the heating speed, realize the heating concentrated on the workpiece surface, limit the heat affected zone, realize the highly controllable local area heating. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only a part of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0012] Figure 1 For the high-temperature superconducting tape in the background art of the present application

[0013] Figure 2 The device structure diagram provided by the present application.

[0014] Figure 3 The structure diagram of superconducting tape to superconducting tape welding provided by the present application.

[0015] Figure 4 The structure diagram of superconducting tape to metal joint provided by the present application.

[0016] Figure 5 The structure diagram of superconducting tape to circular metal joint provided by the present application.

[0017] Figure 6 The heating method flowchart provided by the present application.

[0018] Among them: 1 is an induction coil, 2 is a superconducting tape, 3 is a solder, 4 is a metal joint, 5 is an infrared thermal imager, 6 is a high-frequency power supply, 7 is a water cooling system. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] As Figure 2 shown, the embodiment of the present application discloses a high-temperature superconducting joint welding device, comprising: a superconducting joint, a high-frequency power supply, a water cooling system and a thermal imager. Superconducting connectors are used to generate alternating magnetic fields; High-frequency power supplies are used to change the frequency and power of the superconducting connector; The water-cooling system is used to provide cooling for the superconducting connector and the high-frequency power supply; Thermal imagers are used to detect temperature changes in superconducting connectors, high-frequency power supplies, and water-cooling systems in real time.

[0021] In a specific embodiment of the present invention, the welding problem of superconducting joints is addressed. Figure 2 An implementation example is shown. The device consists of seven parts: induction coil 1, superconducting strip 2, solder 3, copper connector 4, infrared thermal imager 5, high-frequency power supply 6, and water cooling system 7.

[0022] Preferably, the superconducting connector includes an induction coil and a welding fixture. The welding fixture is placed stationary at the center of the induction coil. The high-frequency power supply applies high-frequency alternating current to the induction coil and heats the surface of the welding fixture by utilizing the skin effect and eddy current effect.

[0023] Specifically, the welding fixture includes a superconducting strip, solder, and a copper connector, with a uniform gap between the superconducting strip, solder, and copper connector.

[0024] In a specific embodiment of the present invention, the induction coil 1 is a hollow copper tube, and the size and shape of the copper tube can be changed according to the welding fixture.

[0025] Furthermore, the welding fixture is stationary at the center of the induction coil 1, but can be moved along the direction of the center of the induction coil 1.

[0026] In another specific embodiment of the present invention, such as Figure 2 As shown, there is a certain gap (about 1 cm) between the induction coil 1 and the workpiece to be welded, and the gap is uniform. When there is no workpiece to be heated in the coil, an alternating magnetic field is generated around the induction coil. Due to the eddy current effect and skin effect, this magnetic field generates heat on the surface of the workpiece closest to the induction coil. This method first continuously changes the position of the workpiece and the frequency and power of the induction power supply for a specific size of workpiece. Then, this continuous process of position, frequency, and power is discretized, and the heating effect of each combination of position, frequency, and power is calculated and experimented on. The data is stored in a predetermined database. Then, according to the user's requirements for solders with different melting points (Sn63Pb: 183℃, Sn42Bi58: 138℃, etc.), the optimal position, frequency, and power are searched from the database. The characteristic of this method is that once the position, frequency, and power are selected, they will not be moved or changed during the heating process. During the heating process, the infrared thermal imager 5 monitors the temperature distribution of the welding fixture in real time and stops the heating if the temperature exceeds the limit. To prevent temperature overshoot after the heating is stopped, the control temperature is reduced, that is, the heating is turned off in advance.

[0027] The working principle is as follows: firstly, the superconducting tape 2 to be welded, the solder 3, and the copper joint 4 are fixed tightly to form a welding tool assembly; secondly, the welding tool is placed in the center of the induction coil 1 or adjusted along the central axis and kept stationary; thirdly, the water cooling system 7 is started to provide cooling for the internal transformer of the high-frequency power supply and the induction coil 1, and the infrared thermal imager 5 is started to monitor the joint temperature distribution; then the frequency, power, time, and temperature safety threshold of the high-frequency power supply 6 are set; finally, the power supply is started with one key. The device follows the skin effect (induction current concentrates on the surface of the workpiece), and the higher the frequency, the more significant the effect. The heating energy is precisely concentrated on the joint surface area by using this effect, and other parts are not affected by heat. This method is suitable for various joint types such as superconducting-superconducting or superconducting-non-superconducting metal (such as copper terminals) (see Figure 3 、 Figure 4 、 Figure 5 ). By high-frequency induction heating, the solder is fully melted, and after solidification, the superconducting materials are firmly connected between or with the metal copper terminal, forming a complete superconducting joint.

[0028] Specifically, as shown in Figure 6 , a heating method of a high-temperature superconducting joint welding device includes the following steps: Initial preparation: after fixing the superconducting tape, solder, and copper joint, the welding workpiece is placed in the induction coil, and the water cooling system and thermal imager are started; Parameter setting: the key parameters of the high-frequency power supply are set in advance, including working frequency, output power, heating time, and preset temperature safety threshold; Heating control: start the high-frequency power supply, and the thermal imager continuously scans the surface temperature distribution of the welding workpiece; Temperature judgment: the water cooling system judges whether the temperature of the welding workpiece reaches the preset threshold in real time, stops heating when the preset value is reached, and forms a high-strength superconducting joint after cooling.

[0029] In a specific embodiment of the present application, the automatic control process of the high-temperature superconducting joint welding device: the core is to realize temperature closed-loop control through thermal imager feedback, to ensure the quality of high-frequency induction heating welding (solder is fully melted), while strictly preventing over-temperature risk, and ensuring process safety and joint reliability. The control method is divided into the following 4 steps.

[0030] Initial preparation: after fixing the superconducting tape, solder, and copper joint, the superconducting tape is embedded into the notch of the copper joint through bending at one end, ensuring that the superconducting tape does not slide when there is tension, and the other end maintains a constant tension to pull the superconducting tape; that is, the superconducting tape is embedded into the notch of the copper joint (such as Figure 5 , notch) through bending at one end, and the other end maintains a constant tension (such as Figure 5(Tension) Pull the superconducting strip again to ensure that the superconducting strip, solder and copper joint do not slip; form a welded workpiece and place the welded workpiece in the induction coil, start the water cooling system (to prevent overheating) and the thermal imager (to monitor the temperature in real time).

[0031] Parameter settings: Pre-configure key power supply parameters, including operating frequency, output power, heating time, and preset temperature safety threshold.

[0032] Heating control: The high-frequency heating device is activated, and the thermal imager continuously scans the temperature distribution on the workpiece surface. The system determines in real time whether the preset threshold has been reached: if the temperature is ≥ the threshold, the power is immediately cut off (to prevent overheating and damage to the workpiece); if the temperature is < the threshold, heating continues until the solder is completely melted.

[0033] Final shaping: The molten solder solidifies to form a dense, high-strength superconducting joint through natural cooling or air cooling.

[0034] Specifically, the heating control includes: a high-frequency power supply forming a preset alternating magnetic field within the induction coil; When the welding fixture is placed in an alternating magnetic field, eddy currents are formed on the surface of the welding fixture under the action of the alternating magnetic field, thereby heating the surface of the welding fixture. By continuously changing the relative position of the welding fixture and the induction coil, as well as the frequency and power of the high-frequency power supply, the process of continuously changing the position, frequency, and power is discretized. The heating effect of the welding fixture at each position is calculated and tested to obtain heating effect data. Store the heating effect data in the database; Based on user needs, the optimal heating effect data is retrieved from the database to heat the welding fixture, thereby obtaining the optimal heating effect.

[0035] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high temperature superconducting joint welding apparatus, characterized by, The application relates to a superconducting joint, a high-frequency power supply, a water cooling system and a thermal imager. The superconducting joint is used for forming an alternating magnetic field. The high-frequency power supply is used for changing the frequency and power of the superconducting joint. The water cooling system is used for cooling the superconducting joint and the high-frequency power supply. The thermal imager is used for detecting the temperature changes of the superconducting joint, the high-frequency power supply and the water cooling system in real time. The superconducting joint comprises an induction coil and a welding tool, the welding tool is fixed at the center of the induction coil, the high-frequency power supply is used for applying high-frequency alternating current to the induction coil, and the surface of the welding tool is heated by using the skin effect and the eddy current effect.

2. A high temperature superconducting joint welding apparatus according to claim 1, wherein The welding tool comprises a superconducting tape, a solder and a copper joint, and uniform gaps exist among the superconducting tape, the solder and the copper joint.

3. A high temperature superconducting joint welding apparatus according to claim 2, wherein The application comprises the following steps:

4. A heating method for a high temperature superconducting joint welding apparatus, characterized by, initial preparation: the superconducting tape, the solder and the copper joint are fixed to form a welding workpiece, the welding workpiece is placed in the induction coil, and the water cooling system and the thermal imager are started; parameter setting: key parameters of the high-frequency power supply are set in advance, including working frequency, output power, heating time and preset temperature safety threshold; heating control: the high-frequency power supply is started, and the thermal imager continuously scans the surface temperature distribution of the welding workpiece; temperature judgment: the water cooling system judges whether the temperature of the welding workpiece reaches the preset threshold in real time, heating is stopped when the preset threshold is reached, and a high-strength superconducting joint is formed after cooling. The heating control specifically comprises the following steps: the high-frequency power supply forms a preset alternating magnetic field in the induction coil; 5. The heating method of a high temperature superconducting joint welding apparatus according to claim 4, characterized by, the welding tool is placed in the alternating magnetic field, and the surface of the welding tool forms an eddy current under the action of the alternating magnetic field, so that the surface of the welding tool is heated; the relative position of the welding tool and the induction coil and the frequency and power of the high-frequency power supply are continuously changed, the process of continuously changing the position, the frequency and the power is discretized, the heating effect of the welding tool at each position is calculated and experimented, and heating effect data is obtained; the heating effect data is stored in a database; the welding tool is heated according to the optimal heating effect data in the database according to user demand, and the optimal heating effect is obtained. ​

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