Asymmetric traveling wave superconducting flux pump, power supply method and superconducting magnet excitation system

Abstract

The invention belongs to the technical field of flux pumps, and relates to an asymmetric traveling wave superconducting flux pump, a power supply method and a superconducting magnet excitation system. The asymmetric traveling wave superconducting flux pump comprises a magnetic conductive iron core, three coil groups and a magnet yoke, the magnetic conductive iron core is provided with tooth grooves. Each coil group comprises a plurality of coils; each coil group is used as a power supply input phase, and the three-phase cores are connected to form three coil groups which are connected to form a three-phase alternating current coil; the three-phase AC coil is powered by an AC power supply; the magnet yoke and the side surface of the magnetic conductive iron core form a magnetic coupling air gap; and after the three-phase alternating current coil is electrified, an unbalanced traveling wave magnetic field is generated at the magnetic coupling air gap. A rectified alternating current power supply is used for supplying power to the asymmetric traveling wave superconducting flux pump, an unbalanced traveling wave magnetic field is generated at a magnetic coupling air gap, and current is generated in a superconducting excitation loop; the alternating current power supply is adopted for supplying power, the size of the magnetic flux pump and a superconducting magnet excitation system is effectively reduced, and industrial application of the asymmetric traveling wave superconducting magnetic flux pump is promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic flux pumps, and in particular relates to an asymmetric traveling wave superconducting magnetic flux pump, a power supply method and a superconducting magnet excitation system. Background Art

[0002] Superconducting magnets are a crucial component of superconducting power applications. Compared to traditional permanent magnets and ordinary electromagnets, they are lightweight and compact, can generate stronger magnetic fields, and have extremely low losses. Their superior performance has led to their application in numerous fields, including medicine, energy, and transportation. Superconducting magnets are key components of various superconducting devices, providing high-intensity and highly stable magnetic fields. Low-temperature superconducting magnet equipment is gradually replacing permanent magnets and conventional conductor imaging equipment. However, due to the scarcity of liquid helium, operating costs are rising year by year, necessitating the development of liquid helium-free high-temperature superconducting systems to meet future demand. However, a problem that prevents the widespread application of high-temperature superconducting coil technology is its inability to operate in continuous current mode.

[0003] Due to current losses caused by flux creep and welding resistance, the current decay in the closed circuit of a high-temperature superconducting magnet is non-negligible. The traditional power supply method uses a pair of thick metal current leads to connect a conventional superconducting power source at room temperature to the superconducting magnet at low temperature. To operate a superconducting magnet in continuous current mode, a continuous and uninterrupted power supply is required. For the entire magnet system, these current leads must be connected to the cryogenic dewar. These current leads impose a significant heat load on the entire system, significantly increasing operating costs.

[0004] Flux pump technology enables contactless excitation of high-temperature superconducting magnets, eliminating heat leakage caused by current leads. Currently, there are two main types of flux pumps worldwide: traveling wave flux pumps and rectifier flux pumps. Traveling wave flux pumps can be further divided into linear motor flux pumps, rotary permanent magnet flux pumps, and linear flux pumps. Asymmetric traveling wave superconducting flux pumps are primarily composed of three-phase AC coils and DC coils, requiring power from three-phase AC and DC, respectively. They generate biased traveling waves at the air gap, which in turn couple to superconducting flux quanta for pumping power. However, excessive power supplies can hinder the application and promotion of flux pumps. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides an asymmetric traveling wave superconducting flux pump without a DC bias coil and a power supply method.

[0006] In a first aspect, the present invention provides an asymmetric traveling wave superconducting flux pump, comprising a magnetically conductive core, three coil groups, and a magnetic yoke; The magnetic conductive core is provided with teeth slots for winding the coil; Each coil group includes several coils; each coil group serves as a power input phase, and three coil groups are connected to form a three-phase AC coil; the three-phase AC coil is powered by an AC power supply; The magnetic yoke and the side surface of the magnetic conductive core form a magnetic coupling air gap; When the three-phase AC coil is energized, an unbalanced traveling wave magnetic field is generated at the magnetic coupling air gap.

[0007] In a second aspect, the present invention provides a method for powering an asymmetric traveling wave superconducting flux pump, which utilizes a pulse voltage to power a three-phase AC coil of the asymmetric traveling wave superconducting flux pump.

[0008] In a third aspect, the present invention provides a superconducting magnet excitation system based on the asymmetric traveling wave superconducting flux pump, comprising: Asymmetric traveling-wave superconducting flux pump; a superconducting stator disposed at the magnetic coupling air gap; and superconducting coils; The superconducting coil and the superconducting stator are connected to form a closed loop; The asymmetric traveling wave superconducting flux pump (8) generates an unbalanced traveling wave magnetic field at the magnetic coupling air gap. The unipolar traveling wave magnetic field acts on the superconducting stator, driving the magnetic flux quanta in the superconducting stator to move in a directional manner, generating a DC voltage to power the superconducting coil. Based on the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, a three-phase AC power source is used to supply power to the three-phase AC coil via a copper wire.

[0010] Furthermore, the pulse voltage is used to power the three-phase AC coil of the asymmetric traveling wave superconducting flux pump.

[0011] Furthermore, the pulse voltage is the output voltage of a pulse power supply or the pulse voltage after diode rectification.

[0012] Furthermore, after diode rectification, the air gap magnetic field is an unbalanced traveling wave magnetic field, and the pulse voltage output by the power supply after diode rectification is a unipolar pulse voltage.

[0013] Furthermore, the superconducting stator is a high-temperature superconducting ReBCO strip, including a Hastelloy substrate layer, a ReBCO layer and a buffer layer arranged in sequence from top to bottom.

[0014] Furthermore, the superconducting coil is formed by stacking a single or multiple superconducting double-pancake coils; the superconducting double-pancake coil is wound with ReBCO high-temperature superconducting tape, and each superconducting double-pancake coil has two tape wire ends.

[0015] The beneficial effects of the present invention are as follows: the present invention uses three-phase alternating current to power an asymmetric traveling wave superconducting flux pump, which can directly generate an unbalanced traveling wave magnetic field at the magnetic coupling air gap, and then generate current in the superconducting excitation circuit; using an AC power supply to power the asymmetric traveling wave superconducting flux pump can effectively reduce the volume of the flux pump and its ancillary equipment, and promote the industrial application of superconducting flux pumps. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of an asymmetric traveling-wave superconducting flux pump provided in Example 1 of the present invention; Figure 2 A schematic diagram of a power supply method for an asymmetric traveling-wave superconducting flux pump provided in Example 2 of the present invention; Figure 3 Schematic diagram of the superconducting magnet excitation system based on an asymmetric traveling wave superconducting flux pump.

[0017] Icon: 1-magnetic core; 2-coil; 3-yoke; 4-magnetic coupling air gap; 5-diode; 6-superconducting stator; 7-superconducting coil; 8-asymmetric traveling wave superconducting flux pump; U1-AC power supply. DETAILED DESCRIPTION

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of 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. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0019] Example 1 As an example, as shown in the attached Figure 1 As shown, in order to solve the above technical problems, this embodiment provides an asymmetric traveling wave superconducting flux pump, including a magnetic conductive core 1, three coil groups and a magnetic yoke 3; The magnetic core 1 is provided with teeth for winding the coil; Each coil group includes a plurality of coils 2; each coil group serves as a power input phase, and three coil groups are connected to form a three-phase AC coil; the three-phase AC coil is powered by an AC power supply; The magnetic yoke 3 and the side surface of the magnetic conductive core 1 form a magnetic coupling air gap 4; After the three-phase AC coil is energized, an AC unbalanced traveling wave magnetic field is generated at the magnetic coupling air gap 4.

[0020] In actual applications, for example, the asymmetric traveling-wave superconducting flux pump includes a magnetic core and nine groups of copper coils. The nine coils are divided into three groups, with three coils forming a phase, and the three phases are connected in a star configuration. A three-phase AC power supply is used to power the three-phase AC coils. Powering the three-phase AC coils generates an unbalanced traveling-wave magnetic field at the magnetic coupling air gap 4. A superconducting stator is placed in the magnetic coupling air gap 4 of the asymmetric traveling-wave superconducting flux pump to generate a DC voltage. The asymmetric traveling-wave superconducting flux pump, which does not require a DC bias power supply, has the advantage of being compact.

[0021] Optionally, a pulse voltage is used to power the three-phase AC coil of the asymmetric traveling wave superconducting flux pump.

[0022] In actual application, the output of current is achieved through three copper wires, and the size and frequency of the pulse current are adjusted.

[0023] The asymmetric traveling-wave superconducting flux pump structure uses a pulsed direct current (DC) power source or a rectified three-phase AC power source to power the flux pump coil. This generates an unbalanced traveling-wave magnetic field directly at the magnetic coupling air gap, which in turn generates current in the superconducting excitation circuit. This invention uses a three-phase AC power source to power the asymmetric traveling-wave superconducting flux pump, effectively reducing the size of the flux pump and its associated equipment, and promoting the industrial application of flux pump technology.

[0024] Example 2 Based on the asymmetric traveling wave superconducting flux pump shown in Example 1 of the present invention, an embodiment of the present invention further provides a power supply method for the asymmetric traveling wave superconducting flux pump, as shown in the attached Figure 2 As shown, a pulse voltage is used to power the three-phase AC coil of the asymmetric traveling wave superconducting flux pump. The pulse voltage is generated by an AC power supply U1.

[0025] Optionally, the pulse voltage is the output voltage of a pulse power supply or the pulse voltage after diode rectification.

[0026] Optional, as attached Figure 2 As shown, after the diode 5 is rectified, the air gap magnetic field is an unbalanced traveling wave magnetic field, and the pulse voltage output by the power supply after the diode rectification is a unipolar pulse voltage.

[0027] Example 3 Based on the asymmetric traveling wave superconducting flux pump shown in Example 1 of the present invention, as shown in the attached Figure 3 As shown, an embodiment of the present invention further provides a superconducting magnet excitation system based on the asymmetric traveling wave superconducting flux pump, comprising: Asymmetric traveling wave superconducting flux pump 8; a superconducting stator 6 disposed at the magnetic coupling air gap; and Superconducting coil 7; The superconducting coil 7 and the superconducting stator 6 are connected to form a closed loop; The asymmetric traveling wave superconducting flux pump 8 generates an unbalanced traveling wave magnetic field at the magnetic coupling air gap. The unipolar traveling wave magnetic field acts on the superconducting stator 6, driving the magnetic flux quanta in the superconducting stator 6 to move in a directional manner, generating a DC voltage to power the superconducting coil 7.

[0028] In actual use, the asymmetric traveling-wave superconducting flux pump 8 is powered by an AC power supply U1. This asymmetric traveling-wave superconducting flux pump, without a DC bias coil, offers a simpler structure, smaller size, and greater energy efficiency. Without a DC bias coil, the asymmetric traveling-wave superconducting flux pump generates a unipolar traveling-wave magnetic field at the magnetic coupling air gap. This magnetic field acts on the superconducting stator, driving the directional movement of magnetic flux quanta within the stator. This generates a DC voltage within the stator, which in turn powers the superconducting coil.

[0029] The asymmetric traveling wave superconducting flux pump serves as the power source for the superconducting coils, and a superconducting stator is placed at the air gap to generate DC current.

[0030] Optionally, the superconducting stator 6 is a high-temperature superconducting ReBCO strip, including a Hastelloy substrate layer, a ReBCO layer and a buffer layer arranged in sequence from top to bottom.

[0031] In practical applications, the superconducting stator uses a 10mm-wide superconducting tape, which is connected in series with the superconducting magnet to form a closed loop. ReBCO is a superconducting material, where Re represents a rare earth element. Typically, the operating temperature of a superconducting magnet is below 90 K.

[0032] Optionally, the superconducting coil 7 is formed by stacking a single or multiple superconducting double-pancake coils; the superconducting double-pancake coils are wound with ReBCO high-temperature superconducting tapes, and each superconducting double-pancake coil has two tape ends.

[0033] Generally, superconducting stators and superconducting magnets are cooled to a superconducting state using a refrigerator or cold helium gas. Superinsulating materials are used to block heat between the superconducting stator and the magnetic elements in the dewar, thereby ensuring that the heat of the magnetic elements will not be transferred to the low-temperature dewar system, affecting the stability of the superconducting stator performance.

[0034] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. Asymmetric traveling wave superconducting flux pump, characterized in that: It includes a magnetic conductive core (1), a three-phase coil group and a magnetic yoke (3); The magnetic conductive core (1) is provided with tooth slots for winding the coil; Each phase coil group includes a plurality of coils (2); each phase coil group serves as a power input phase, and three coil groups are connected to form a three-phase AC coil; the three-phase AC coil is powered by an AC power supply; The magnetic yoke (3) and the side surface of the magnetic permeable core (1) form a magnetic coupling air gap (4); When the three-phase AC coil is energized, an asymmetric traveling wave magnetic field is generated at the magnetic coupling air gap (4).

2. The asymmetric traveling wave superconducting flux pump according to claim 1, characterized in that: The three-phase AC power supply is used to supply power to the three-phase AC coil through copper wires.

3. Asymmetric traveling wave superconducting flux pump power supply method, characterized in that: include: A pulse voltage is used to power the three-phase AC coil of the asymmetric traveling wave superconducting flux pump according to any one of claims 1-2.

4. The asymmetric traveling wave superconducting flux pump power supply method according to claim 3, characterized in that: The pulse voltage is the output voltage of the pulse power supply or the pulse voltage after diode rectification.

5. The asymmetric traveling wave superconducting flux pump power supply method according to claim 3, characterized in that: After diode rectification, the air gap magnetic field is an unbalanced traveling wave magnetic field, and the pulse voltage output by the power supply after diode rectification is a unipolar pulse voltage.

6. A superconducting magnet excitation system based on the asymmetric traveling wave superconducting flux pump according to any one of claims 1-2, characterized in that: include: The asymmetric traveling wave superconducting flux pump (8) according to any one of claims 1-2; a superconducting stator (6) disposed at the magnetic coupling air gap; and Superconducting coil (7); The superconducting coil (7) is connected to the superconducting stator (6) to form a closed loop; The asymmetric traveling wave superconducting flux pump (8) generates an unbalanced traveling wave magnetic field at the magnetic coupling air gap. The unipolar traveling wave magnetic field acts on the superconducting stator (6), driving the magnetic flux quanta in the superconducting stator (6) to move in a directional manner, thereby generating a DC voltage to power the superconducting coil (7).

7. The superconducting magnet excitation system according to claim 6, characterized in that: The superconducting stator (6) is a high-temperature superconducting ReBCO strip, comprising a Hastelloy substrate layer, a ReBCO layer and a buffer layer arranged in sequence from top to bottom.

8. The superconducting magnet excitation system according to claim 6, characterized in that: The superconducting coil (7) is formed by stacking a single or multiple superconducting double-pancake coils; the superconducting double-pancake coils are wound with ReBCO high-temperature superconducting tapes, and each superconducting double-pancake coil has two tape ends.

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