A background magnetic field simulation and testing device for superconducting coil quench detection and electromagnetic characteristic analysis of an electric machine

Abstract

The application belongs to the technical field of superconducting motor testing, and more particularly relates to a background magnetic field simulation and testing device for superconducting coil quench detection and electromagnetic characteristic analysis of a motor. The device comprises coaxially arranged outer and inner stator cores, an open or closed cryogenic container with a built-in superconducting coil device, and a device support; the outer stator is composed of an outer stator core and multiphase armature windings embedded in the tooth slots of the outer stator core; the inner stator core is composed of an even-pole core salient pole and a pole shoe, and an air gap is formed between the two; the cryogenic container can be of an open structure or a closed structure, and can be flexibly selected according to different testing requirements; by passing a symmetric alternating current into the multiphase armature windings of the outer stator, the background magnetic field environment of the superconducting coil in the motor operation is simulated, effective verification and quantitative analysis of the superconducting coil quench characteristics and electromagnetic performance are realized, the related tests can be completed without manufacturing a prototype, and the experimental cost is significantly reduced, and the safety and reliability are improved.

Description

Technical Field

[0001] This invention belongs to the technical field of superconducting motor testing, and more specifically, relates to a background magnetic field simulation and testing device for quench detection and electromagnetic characteristic analysis of superconducting coils in motors. Background Technology

[0002] In recent years, high-temperature superconducting (HTS) motors have become a research hotspot in the field of motor technology due to their core advantages such as high power density, lightweight design, and high efficiency. Compared to traditional motors, HTS motors use superconducting coils instead of conventional conductive materials, exhibiting zero resistance at low temperatures and significantly improving current carrying capacity, thereby achieving a stronger magnetic field output in a smaller volume. This characteristic makes them promising for applications in scenarios with stringent requirements for equipment compactness and energy efficiency, such as ship propulsion, wind power generation, and aerospace.

[0003] Chinese invention patent CN116500440A discloses a testing device for the current-carrying characteristics and AC losses of high-temperature superconducting windings, including a cryogenic Dewar container, a high-permeability magnetic core device, a superconducting coil, an excitation power supply, measuring instruments, and a control platform. The liquid nitrogen Dewar container serves as the outer shell of the device, providing a cryogenic environment for testing the superconducting winding performance. The high-permeability magnetic core device consists of an upper stator core and a lower mover core. The stator core is designed with a structure commonly used in superconducting motors. The superconducting winding under test is wound around the slots of the core and supported by a coil bracket above the superconducting excitation winding. The superconducting excitation coil is placed in the teeth of the mover core.

[0004] However, its engineering application faces two major challenges: first, the reliability of quench detection is insufficient, as traditional methods are susceptible to induced voltage interference, making real-time and accurate monitoring difficult; second, electromagnetic characteristic testing relies on simplified simulation models or full prototype verification, leading to prediction errors, extended development cycles, and increased costs. To address the quench detection problem, our team proposes a detection method based on the differential voltage at the ends of symmetrically positioned superconducting coils, which can achieve detection without altering the motor structure. However, the above methods and related performance tests still rely on the real motor magnetic field environment. Limited by the lack of experimental devices capable of simulating complex background magnetic fields, verification work still depends on high-cost prototype manufacturing. Therefore, there is an urgent need to develop a dedicated device capable of simulating the background magnetic field of motor operation conditions to achieve repeatable verification of the quench detection method and quantitative evaluation of the electromagnetic characteristics of the superconducting coil, thereby reducing testing costs and improving system safety margins. Summary of the Invention

[0005] The present invention aims to overcome at least one of the defects of the prior art and provide a background magnetic field simulation and testing device for quench detection and electromagnetic characteristic analysis of superconducting coils of motors. This solves the problem that the lack of a dedicated device in the current laboratory environment that can simulate the complex background magnetic field of motors leads to the limitation of quench detection method verification and superconducting coil performance testing on the high cost of prototype manufacturing.

[0006] The detailed technical solution of this invention is as follows:

[0007] This invention provides a background magnetic field simulation and testing device for quench detection and electromagnetic characteristic analysis of superconducting coils in electric motors, comprising: an outer stator, an inner stator core, a cryogenic container, a device support, and a superconducting coil device;

[0008] The outer stator includes an outer stator core and an armature winding embedded in the slots of the outer stator core. The outer stator core has evenly distributed alternating slots on its inner circumferential surface, and a multi-phase armature winding is embedded in the slots to form a complete armature winding system. The inner stator core includes circumferentially symmetrical even-numbered pole core salient poles and matching pole shoes.

[0009] The inner diameter of the outer stator core is larger than the outer diameter of the inner stator core, and the outer stator core and the inner stator core are arranged coaxially. An air gap is left between the inner diameter of the outer stator core and the outer diameter of the inner stator core. The air gap can be either a uniform air gap or a non-uniform air gap, so as to carry out electromagnetic performance analysis and withstand evaluation of superconducting coils under complex magnetic field conditions under different conditions.

[0010] The device support includes a support base plate and a support plate vertical plate. Two outer stator core supports are fixed on the left and right sides of the support plate vertical plate respectively to fix the left and right ends of the outer stator core. The outer stator core lower support is fixed on the support base plate to fix the lower end of the outer stator core.

[0011] The cryogenic container support is fixed on the vertical plate of the support plate and is used to place the cryogenic container; at the same time, the cryogenic container is fixed on the cryogenic container support, and a central through hole is provided between the cryogenic container support and the cryogenic container, so that the salient pole and pole shoe of the inner stator core pass through the central through hole and are fixed at the end.

[0012] Each cryogenic container contains a superconducting coil device and is filled with cryogenic coolant to ensure the normal operation and thermal stability of the superconducting coil in a cryogenic environment.

[0013] Furthermore, the cryogenic container includes an open cryogenic container and a closed cryogenic container;

[0014] Cryogenic container supports include upper and lower cryogenic container supports and inclined cryogenic container supports;

[0015] The upper and lower cryogenic container supports house open cryogenic containers, while the inclined cryogenic container supports house closed cryogenic containers.

[0016] The open-type cryogenic container is a topless, loop-shaped structure that allows for direct injection of cryogenic coolant and level control. The open-type cryogenic container facilitates active quench control during experiments and simplifies the coolant addition and maintenance process.

[0017] The closed cryogenic container is a fully enclosed loop-shaped structure container. The cryogenic coolant is injected through the coolant delivery pipe, which can effectively prevent coolant leakage and improve coolant utilization efficiency.

[0018] Furthermore, the open cryogenic container is a U-shaped structure with a central through hole. The bottom surface of its inner ring has a through central through hole, and the bottom surface of its outer ring is a closed surface. A superconducting coil device is fixedly placed inside the U-shaped cavity of the open cryogenic container.

[0019] The inner stator core salient pole and pole shoe pass through the central through hole, so that the magnetic flux generated by the energization of the outer stator armature winding is guided through the inner stator core pole shoe and inner stator core salient pole magnetic circuit and concentrated through the superconducting coil, generating an induced voltage inside the coil.

[0020] Furthermore, the enclosed cryogenic container includes a container body, a container lid, and a piping assembly;

[0021] The container body is based on the structure of an open cryogenic container, and its outer wall is provided with openings for the inlet and outlet of coolant medium or for the installation of components.

[0022] The container lid covers and is fixed to the U-shaped cavity opening of the container body, forming a closed and sealed structure;

[0023] The piping assembly includes a coolant delivery pipe and an electrical lead pipe, and is installed at the opening in the container body.

[0024] Furthermore, the superconducting coil device includes a superconducting coil and a support frame;

[0025] The superconducting coil is suspended inside the cryogenic container by a support frame, and a gap is maintained between the superconducting coil and the container wall to achieve non-contact fixation.

[0026] Furthermore, the outer stator core and the inner stator core are manufactured by laminating silicon steel sheets.

[0027] Furthermore, the superconducting coil is provided with voltage leads and current leads;

[0028] The voltage lead is connected to a high-precision nanovoltmeter for measuring the terminal voltage of the superconducting coil;

[0029] The current lead is connected to a DC power supply to provide DC current to the superconducting coil.

[0030] Furthermore, the device also includes an armature winding power supply system;

[0031] The armature winding power supply system is connected to the armature winding of the outer stator and is used to provide multiphase alternating current to the armature winding.

[0032] Furthermore, the armature winding power supply system adopts a combination of programmable AC current source or inverter and DC power supply, and the amplitude and frequency of the output alternating current are adjustable; the armature winding power supply system is directly connected to the multi-phase output terminals of the armature winding, and different background magnetic field environments can be simulated by adjusting the amplitude and frequency parameters of the output current.

[0033] Furthermore, the air gap between the outer stator core and the inner stator core is either uniform or non-uniform. The uniform air gap is used to simulate the standard symmetrical background magnetic field under normal operating conditions of the motor, while the non-uniform air gap is used to simulate the asymmetrical background magnetic field presented under non-ideal operating conditions of the motor.

[0034] Precise adjustment of the air gap thickness can be achieved by precisely controlling the thickness and installation position of the non-magnetic pad.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] This invention provides a background magnetic field simulation and testing device for quench detection and electromagnetic characteristic analysis of superconducting coils in electric motors. By constructing an outer stator integrating a multiphase armature winding system and introducing symmetrical alternating currents into the multiphase armature winding system, the device can simulate the time-varying background magnetic field environment experienced by the superconducting coil under motor operating conditions. By combining an open or closed cryogenic container structure, selected according to different testing targets, the device can effectively verify the quench detection method for superconducting motors and quantitatively analyze the electromagnetic characteristics of the superconducting coil. This design significantly reduces the verification cost of traditional integrated testing and greatly improves the safety and reliability of the testing process. It enables researchers to efficiently verify the quench detection method for superconducting coils and deeply analyze their electromagnetic characteristics without manufacturing a complete prototype. Furthermore, the generated controllable magnetic field is also applicable to the study of the electromagnetic characteristics of superconducting bulk / strip materials. Attached Figure Description

[0037] Figure 1 This is a three-dimensional structural diagram of Embodiment 1 of the present invention;

[0038] Figure 2 This is a three-dimensional structural diagram of the main body of the device in Embodiment 1 of the present invention;

[0039] Figure 3 A three-dimensional structural diagram of the cryogenic container configuration of the four-pole inner stator core in Embodiment 2 of the present invention;

[0040] Figure 4 This is a three-dimensional structural diagram of the open-type cryogenic container in Embodiment 1 of the present invention;

[0041] Figure 5 This is a three-dimensional structural diagram of the closed cryogenic container in Embodiment 1 of the present invention;

[0042] Figure 6 This is a three-dimensional structural diagram of the superconducting coil device I of the present invention;

[0043] Figure 7 This is a three-dimensional structural diagram of the superconducting coil device II of the present invention.

[0044] Figure label:

[0045] 1. Outer stator; 11. Outer stator core;

[0046] 2. Inner stator core; 21. Core salient pole; 22. Pole shoe;

[0047] 3. Cryogenic containers; 31. Open cryogenic containers; 32. Closed cryogenic containers; 321. Container body; 322. Container lid; 323. Piping assemblies; 3231. Coolant delivery pipe; 3232. Electrical lead pipe.

[0048] 4. Device support; 41. Support base plate; 42. Support plate vertical plate; 43. Outer stator core support; 44. Outer stator core lower support; 40. Cryogenic container support; 45. Upper and lower cryogenic container supports; 46. Inclined cryogenic container support.

[0049] 5. Superconducting coil assembly; 51. Superconducting coil; 52. Coil frame; 53. Copper pressure plate; 54. Copper busbar; 55. Insulating gasket; 56. Pad block; 57. Open-side constraint frame; 58. Current lead; 59. Voltage lead.

[0050] 6. Armature winding power supply system; 7. DC power supply; 8. High-precision nanovoltmeter. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0052] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0053] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0054] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0055] Example 1

[0056] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0057] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] To facilitate a detailed explanation of the invention, without losing generality, the invention is established... xyz Reference coordinate system, where, xoy The plane is considered to be a horizontal plane, in which x The positive side of the axis is defined as the front side. x The negative side of the shaft is defined as the rear side. y The positive side of the axis is defined as the right side. y The negative side of the axis is defined as the left side, and... xoy The plane perpendicular to is z axis, z The positive side of the axis is defined as the upper side. z The negative side of the axis is defined as the lower side.

[0059] This invention provides a background magnetic field simulation and testing device for quench detection and electromagnetic characteristic analysis of superconducting coils in electric motors, such as... Figure 1 , Figure 2 As shown, it includes an outer stator 1, an inner stator core 2, a cryogenic container 3, a device support 4, and a superconducting coil device 5, wherein:

[0060] The outer stator 1 includes an outer stator core 11 and an armature winding embedded in the slots of the outer stator core. The outer stator core 11 has evenly distributed alternating slots on its inner circumferential surface, and a multi-phase armature winding is embedded in the slots. The inner stator core 2 includes circumferentially symmetrical even-numbered pole salient poles 21 and matching pole shoes 22.

[0061] Preferably, the inner circumferential surface of the outer stator core 11 is uniformly distributed with multiple stator teeth and stator slots, which are alternately distributed. The multiphase armature winding is embedded in these stator slots, forming a complete armature winding system. In this embodiment, the inner stator core 2 adopts a six-pole salient pole structure. This structure is composed of six-pole salient poles 21 and six matching pole shoes 22, forming a circumferentially symmetrical magnetic circuit structure. Each pole shoe 22 is fixed to the radial end of the inner stator core salient pole 21 by a fastening bolt assembly. Each pole shoe 22 has an arc surface concentric with the inner stator core 2.

[0062] The inner diameter of the outer stator core 11 is larger than the outer diameter of the inner stator core 2, and the outer stator core 11 and the inner stator core 2 are arranged coaxially. An air gap is left between the inner diameter of the outer stator core 11 and the outer diameter of the inner stator core 2, so that a circumferential air gap is formed between the outer stator core 11 and the inner stator core 2.

[0063] Preferably, the inner diameter of the outer stator core 11 is designed to be larger than the outer diameter of the inner stator core 2, and the two maintain a strict coaxial alignment relationship. The air gap between the outer stator core 11 and the inner stator core 2 can be set to a uniform or non-uniform state. The uniform air gap is used to simulate the standard symmetrical background magnetic field under normal motor operation conditions, while the non-uniform air gap is used to simulate the asymmetrical background magnetic field presented under motor eccentricity faults, assembly errors, and other extreme and non-ideal conditions, so as to carry out electromagnetic performance analysis and tolerance evaluation of superconducting coils under complex magnetic field conditions.

[0064] Preferably, to ensure uniform circumferential air gap thickness between the outer stator core 11 and the inner stator core 2, multiple precision shims made of non-magnetic material can be installed between the inner and outer stator cores. These shims are of uniform thickness and distribution, effectively ensuring the consistency of the air gap in the circumferential direction, i.e., a uniform air gap. By precisely controlling the thickness and installation position of the non-magnetic shims, precise adjustment of the air gap thickness can be achieved, and non-uniform air gaps can also be ensured, thus guaranteeing the accuracy and reliability of the magnetic field simulation.

[0065] The device support 4 includes a support base plate 41 and a support plate vertical plate 42. Two outer stator core supports 43 are fixed on the left and right sides of the support plate vertical plate 42 respectively, and are used to fix the left and right ends of the outer stator core 11. The outer stator core lower support 44 is fixed on the support base plate 41 and is used to fix the lower end of the outer stator core 11.

[0066] Preferably, the device support 4 includes a horizontally arranged support base plate 41 and a support plate vertical plate 42 that is vertically fixed to the support base plate 41. The support plate vertical plate 42 is preferably rigidly connected to the support base plate 41 by welding, thereby forming a stable support body;

[0067] Specifically, two outer stator core supports 43 are symmetrically arranged on the left and right sides of the support plate vertical plate 42. The outer stator core supports 43 are fixed to the support plate vertical plate 42 by bolts or welding. The outer stator core supports 43 adopt a U-shaped clamp structure and, together with positioning bolts, clamp and fix the left and right sides of the outer stator core 11. The combination of U-shaped clamps and positioning bolts can effectively limit its axial displacement, thereby ensuring the positional stability and structural reliability of the outer stator core during operation.

[0068] Specifically, the support base plate 41 is provided with an outer stator core lower bracket 44 for supporting and fixing the outer stator core 11. The lower bracket 44 is fixed to the upper surface of the support base plate 41 by bolt connection or welding. The outer stator core lower bracket 44 adopts a concave structure design, and its upper part is provided with a support surface that contacts the bottom contour of the outer circle of the core, which is used to support the lower end of the outer stator core 11 and mainly bears the gravity load of the outer stator core 11. The two side walls of the concave structure respectively cooperate with the outer circle surface of the outer stator core 11 to form a double-sided limiting constraint, which effectively prevents the core from moving axially.

[0069] The cryogenic container support 40 is fixed on the vertical plate 42 of the support plate and is used to place the cryogenic container 3. At the same time, the cryogenic container 3 is fixed on the cryogenic container support 40. A central through hole is provided between the cryogenic container support 40 and the cryogenic container 3, so that the salient pole 21 and pole shoe 22 of the inner stator core pass through the central through hole and are fixed at the end.

[0070] Each cryogenic container 3 contains a superconducting coil device 5 and is filled with cryogenic coolant to ensure the normal operation and thermal stability of the superconducting coil in a cryogenic environment.

[0071] The cryogenic container 3 includes an open cryogenic container 31 and a closed cryogenic container 32; the cryogenic container support 40 includes an upper and lower cryogenic container support 45 and an inclined cryogenic container support 46; the upper and lower cryogenic container support 45 houses the open cryogenic container 31, and the inclined cryogenic container support 46 houses the closed cryogenic container 32; the open cryogenic container 31 is a topless, loop-shaped structure container into which cryogenic coolant is directly injected and the liquid level can be controlled; the closed cryogenic container 32 is a fully enclosed, loop-shaped structure container into which cryogenic coolant is injected through a coolant delivery pipe.

[0072] Preferably, in the implementation scheme, the six-pole inner stator core includes upper and lower cryogenic container supports 45 and inclined cryogenic container supports 46.

[0073] The upper and lower cryogenic container supports 45 are symmetrically fixed to the upper and lower surfaces of the support plate vertical plate 42 for mounting the open cryogenic container 31. The upper and lower cryogenic container supports 45 are rigidly fixed to the support plate vertical plate 42 by bolt connection or welding to ensure the stable positioning of the cryogenic container 3. A central through hole is provided on the support surface of the upper and lower cryogenic container supports 45 in contact with the open cryogenic container 31. The inner stator core salient pole 21 passes through the central through hole and is fixed to the upper and lower ends of the inner stator core 2, thereby achieving reliable support and positioning of the inner stator core 2.

[0074] The inclined cryogenic container support 46 is symmetrically fixed on the inclined surface of the support plate vertical plate 42 and is used to place the closed cryogenic container 32. The installation method of the inclined cryogenic container support is the same as that of the upper and lower cryogenic container supports 45. The support surface of the inclined cryogenic container support 46 that contacts the cryogenic container 3 is also provided with a central through hole for fixing the other ends except for the upper and lower ends of the inner stator core 2.

[0075] The enclosed cryogenic container support is essentially the same as the aforementioned inclined cryogenic container support. It still positions and supports the cryogenic container by fixing it to the vertical plate of the support plate, and the support surface is provided with a central through hole to avoid and fix the other ends of the inner stator core other than the upper and lower ends. The difference is that the enclosed cryogenic container support can form a continuous support surface in the circumference, which can fit tightly with the outer wall of the enclosed cryogenic container, further improving its overall stability and anti-displacement ability in cryogenic environments.

[0076] The open-type cryogenic container 31 has a U-shaped structure with a central through-hole, such as... Figure 4 As shown, the bottom surface of the inner ring has a through-hole, and the bottom surface of the outer ring is a closed surface. A superconducting coil device 5 is fixedly placed inside the U-shaped cavity of the open cryogenic container 31. The inner stator core salient pole 21 and pole shoe 22 pass through the through-hole, so that the magnetic flux generated by the energization of the outer stator armature winding is guided through the magnetic circuit of the inner stator core pole shoe 22 and the inner stator core salient pole 21 and concentrated through the superconducting coil, generating an induced voltage inside the coil.

[0077] Preferably, the superconducting coils located on the upper and lower cores employ an open cryogenic container 31. This design allows for flexible adjustment of the coolant coverage of the coils according to experimental requirements: maintaining 100% coverage during electromagnetic characteristic analysis ensures the superconducting coil remains stably in a superconducting state; while in quenching experiments, reducing the coverage promotes a gradual temperature rise in the coils, achieving a controllable and smooth quenching process, which helps control the degree of quenching. The open structure also significantly simplifies the coolant addition and maintenance process. Conversely, the superconducting coils on the circumferential cores on both sides employ a closed cryogenic container with a sealed structure, effectively preventing coolant leakage and improving coolant utilization efficiency. This design is suitable for electromagnetic characteristic testing scenarios requiring long-term maintenance of the superconducting coil's stable superconducting state.

[0078] The enclosed cryogenic container 32 includes a container body 321, a container cover 322, and a pipe assembly 323, such as Figure 5 As shown, the container body 321 is based on the structure of an open cryogenic container 31, and has openings on its walls for the inlet and outlet of coolant medium or for the installation of components; the container cover 322 covers and is fixedly connected to the opening of the container body 321, forming a closed and sealed structure; the pipe assembly 323 includes a coolant delivery pipe 3231 and an electrical lead pipe 3232, and is installed at the opening of the container body 321.

[0079] Preferred, such as Figure 2 As shown, the inner stator core adopts a six-pole structure. The superconducting coils located on the upper and lower cores are enclosed in open cryogenic containers 31. This structure facilitates active quenching operation and control of the quenching degree during the experiment, while simplifying the process of adding and maintaining coolant. The superconducting coils located on the circumferential cores on both sides are enclosed in closed cryogenic containers. These containers have a sealed structure, which can effectively prevent coolant leakage and improve coolant utilization efficiency. They are suitable for scenarios where it is necessary to maintain the stable superconducting state of the superconducting coil for a long time for electromagnetic characteristic analysis.

[0080] Preferably, the closed cryogenic container 32 is constructed by modifying the front side of the main body of the open cryogenic container 31 by opening a hole, and adding a container cover 322 and a pipe assembly 323. The superconducting coil device is placed inside the open cryogenic container 31 after the opening, and all its leads pass through the opening on the front side of the container and are connected to the pipe assembly 323.

[0081] The piping assembly 323 includes a branch pipe and a single-port pipe. The branch pipe is horizontally positioned and has two vertically upward openings at its front end. One opening serves as a coolant delivery pipe 3231, and the other opening serves as an electrical lead pipe 3232. This arrangement allows coolant to flow smoothly into the container, while the vertically upward openings prevent interference between the electrical lead and the main coolant flow path. The single-port electrical lead pipe 3232 is located on the opposite side of the branch pipe and extends vertically upward to smoothly guide the superconducting coil lead to the outside of the container for connection to an external power source or measuring instrument. Finally, the container lid 322 covers the openings and provides a seal, creating a completely closed cryogenic environment.

[0082] The superconducting coil device 5 includes a superconducting coil 51 and a support frame; the superconducting coil 51 is suspended in the cryogenic container 3 by the support frame, and a gap is maintained between the superconducting coil and the wall of the cryogenic container to achieve non-contact fixation.

[0083] Preferably, taking superconducting coil device I as an example: the superconducting coil device 5 includes a superconducting coil 51, a coil frame 52, a copper pressure plate 53, a copper busbar 54, an insulating pad 55, and a pad block 56, as follows. Figure 6 As shown; after the superconducting coil 51 is wound, it is fixed on the coil frame 52. The central through hole of the wound superconducting coil 51 is the same size as the square central through hole at the bottom of the coil frame 52 and is coaxial. The copper pressure plate 53, copper busbar 54, and insulating pad 55 are mainly used for the reliable lead-out and electrical insulation of the current lead of the superconducting coil 51. The superconducting coil 51 is supported by a pad 56 made of low-temperature adaptable material, which keeps it in a non-direct contact state with the bottom wall of the low-temperature container. By reducing the contact area, the heat conduction path is blocked, the heat flow from the bottom wall to the coil is reduced, and the coverage area of ​​the low-temperature cooling medium on the coil is increased to improve the cooling efficiency. It also provides mechanical stress buffer during low-temperature contraction and external vibration to prevent the coil structure from becoming unstable and losing its superconductivity.

[0084] The superconducting coil device 5 can be selected as superconducting coil device II, such as... Figure 7 As shown, the superconducting coil 51 is suspended in a non-contact manner inside the cryogenic container 3 by four open-side constraint frames 57. The constraint frames are made of cryogenic-compatible materials, such as Teflon or stainless steel, and have a C-shaped structure with an opening on one side. The inner contour of the constraint frame is in close contact with the outer surface of the coil frame 52 that fixes the superconducting coil.

[0085] During assembly, the open-side constraint frame 57 is inserted radially into the coil frame 52 from its open side, and self-locking is achieved by the elastic clamping force generated by the pair of arms of the constraint frame acting along the coil axis. At the same time, the bottom of the constraint frame 57 is supported on the inner bottom wall of the cryogenic container 3, thereby forming a predetermined isolation gap between the superconducting coil 51 and the bottom wall of the cryogenic container 3.

[0086] The outer stator core 11 and the inner stator core 2 are manufactured by stacking silicon steel sheets.

[0087] Preferably, in order to reduce the iron loss heating on the outer stator core 11 and the inner stator core 2, the outer stator core 11 and the inner stator core 2 are made by laminating silicon steel sheets. Alternatively, they can be made by laminating materials with similar magnetic permeability to silicon steel sheets, such as nickel-iron alloy FeNi9 or aluminum-magnesium alloy.

[0088] The superconducting coil is provided with voltage leads and current leads; the voltage leads are connected to a high-precision nanovoltmeter 8 for measuring the terminal voltage of the superconducting coil; the current leads are connected to a DC power supply 7 for providing DC current to the superconducting coil.

[0089] Preferably, a copper busbar 54 and an insulating pad 55 are installed on the coil frame 52, and a copper pressure plate 53 is used to fix the lead end of the superconducting tape on the copper busbar 54. The copper pressure plate 53 and the copper busbar 54 have sufficient contact length with the lead end of the superconducting tape. The conductive copper busbar 54 that fixes the lead end of the superconducting coil 51 is connected to the DC power supply 7, and the DC power supply 7 provides the required DC current to the superconducting coil 51.

[0090] Simultaneously, a voltage lead 59 is welded to the lead-out end of the superconducting coil tape. This lead is specifically used for acquiring the superconducting coil terminal voltage signal during the experiment. In practice, the two voltage leads of the superconducting coil are connected to a high-precision nanovoltmeter 8 for real-time monitoring and measurement of the terminal voltage changes during the operation of the superconducting coil. To clearly illustrate the connection relationship, Figure 1 Taking only the upper superconducting coil as an example, the electrical connection between it and the DC power supply and the high-precision nanovolt meter is illustrated. The connection method of the other superconducting coils is the same.

[0091] The device also includes an armature winding power supply system 6; the armature winding power supply system 6 is connected to the armature winding of the outer stator 1 and is used to provide multiphase alternating current to the armature winding.

[0092] Preferably, the armature winding power supply system 6 adopts a combination of a programmable AC current source or an inverter and a DC power supply, and the amplitude and frequency of the output alternating current are adjustable; the armature winding power supply system 6 is directly connected to the multi-phase output terminals of the armature winding, and different background magnetic field environments can be simulated by adjusting the amplitude and frequency parameters of the output current.

[0093] Specifically, this embodiment takes a six-pole model as an example. The assembly process is as follows: First, fix the upper and lower cryogenic container supports 45 and the inclined cryogenic container support 46 to the support plate vertical plate 42 of the device support 4; then fix the open cryogenic container 31 and the closed cryogenic container 32 containing the superconducting coil device 5 to the corresponding upper and lower cryogenic container supports 45 and the inclined cryogenic container support 46; then pass the salient pole of the inner stator core 2 through the central through hole of the cryogenic container 3 and fix it to the pole shoe 22 of the inner stator core 2; finally, put the outer stator 1 with the armature winding in place, adjust the air gap state between the inner stator core 2 and the outer stator core 11, and fix it as a whole by the outer stator core support 43 and the lower outer stator core support 44 to complete the assembly. After assembly, the outer stator armature winding is connected to the armature winding power supply system 6 via the current wire, and the current lead of the superconducting coil is connected to the DC power supply 7. The voltage lead of the superconducting coil is connected to the high-precision nanovoltmeter 8 to measure the terminal voltage data, thus completing the assembly.

[0094] During testing, the effective value was first input to the armature winding of the outer stator 1 armature winding using the armature winding power supply system 6. I , frequency is f After the armature magnetic field reaches a steady-state operating mode, a three-phase symmetrical alternating current is applied to the superconducting coil 51 through the current lead using a DC power supply 7. I dc And the amplitude is increased at a certain rate until the DC current is reached. I dc The amplitude reaches the preset target value. The terminal voltage parameters of the superconducting coil 51 are measured and obtained in real time using a high-precision nanovoltmeter 8. U Simultaneously, the terminal voltage parameters are transmitted through a preset data communication interface. U The data is transmitted to the host computer monitoring system, which then monitors the voltage parameters at the other end. U It enables dynamic visualization, time-series data storage, and generation of change curve graphs.

[0095] If electromagnetic characteristic analysis of the superconducting coil is required, such as testing its current-carrying capacity, the DC current flowing through the superconducting coil 51 inside the sealed cryogenic container 32 can be adjusted. I dcThe current-carrying capacity and other parameters are tested based on the real-time measured terminal voltage value of the high-precision nanovoltmeter 8. When verifying the quench detection method for the superconducting coil inside the motor, under the condition of a stable simulated background magnetic field, the quench of the superconducting coil 51 can be actively induced by reducing the coolant coverage of the superconducting coil 51 in the open cryogenic container 31, and the coil terminal voltage is collected in real-time using the high-precision nanovoltmeter 8. U The quench detection scheme was effectively validated.

[0096] This invention constructs an external stator integrating a multiphase armature winding system and applies symmetrical alternating current to this system to simulate the background magnetic field environment experienced by superconducting coils during actual motor operation. By combining open or closed cryogenic container structures, selected according to different test targets, the invention effectively verifies the quench detection method for superconducting motors and quantitatively analyzes the electromagnetic characteristics of superconducting coils. This system can significantly reduce the testing costs of traditional online testing without manufacturing a prototype and significantly improve the safety and reliability of the testing process.

[0097] Example 2

[0098] The difference from Embodiment 1 is that the inner stator core 2 adopts a four-pole salient pole structure, such as Figure 3 As shown, the structure consists of a cross-shaped quadrupole core salient pole 21 and four matching pole shoes 22, forming a circumferentially symmetrical magnetic circuit structure. Each pole shoe 22 is fixed to the radial end of each pole of the cross-shaped core salient pole 21 by a fastening bolt assembly. Each pole shoe 22 has an arc surface concentric with the inner stator core 2, creating a circumferential air gap between the outer stator core 11 and the inner stator core 2.

[0099] The four-pole salient pole structure includes upper and lower cryogenic container supports 45 and left and right cryogenic container supports, the left and right cryogenic container supports being inclined cryogenic container supports 46;

[0100] Upper and lower cryogenic container supports 45 are symmetrically fixed to the upper and lower surfaces of the support plate vertical plate 42 for mounting open cryogenic containers 31. The open cryogenic containers 31 are rigidly fixed to the support plate vertical plate 42 by bolts or welding to ensure the stable positioning of the cryogenic containers 3. A central through hole is provided on the support surface where the upper and lower cryogenic container supports 45 contact the cryogenic containers 3. The inner stator core salient pole 21 passes through the central through hole and is fixed to the upper and lower ends of the inner stator core 2, thereby achieving reliable support and positioning of the inner stator core 2. Each cryogenic container 3 is independently equipped with a superconducting coil device 5 and contains cryogenic coolant to ensure the normal operation and thermal stability of the superconducting coil in a cryogenic environment.

[0101] Similarly, the left and right cryogenic container supports are symmetrically fixed on the left and right surfaces of the vertical plate 42 of the support plate, and enclosed cryogenic containers 32 are placed on them. The fixing method and structural settings are the same as those of the inclined cryogenic container supports.

[0102] The installation configuration of the even-numbered 2n-pole inner stator core with circumferential symmetry can be obtained through the six-pole salient pole structure and the four-pole salient pole structure.

[0103] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A background magnetic field simulation and testing device for superconducting coil quench detection and electromagnetic property analysis of an electrical machine, characterized in that, The device comprises: an outer stator (1), an inner stator core (2), a low-temperature container (3), a device support (4), and a superconducting coil device (5); the outer stator (1) comprises an outer stator core (11) and an armature winding embedded in the tooth slot of the outer stator core, the inner circumferential surface of the outer stator core (11) is uniformly distributed with alternating tooth slots, and a multi-phase armature winding is embedded in the slots; the inner stator core (2) comprises a plurality of circumferentially symmetrical even-pole core salient poles (21) and matching pole shoes (22); the inner diameter of the outer stator core (11) is greater than the outer diameter of the inner stator core (2), and the outer stator core (11) and the inner stator core (2) are coaxially arranged, with an air gap between the inner diameter of the outer stator core (11) and the outer diameter of the inner stator core (2); the device support (4) comprises a support bottom plate (41) and a support plate vertical plate (42), two outer stator core supports (43) are respectively fixed on the left and right sides of the support plate vertical plate (42) to fix the left and right ends of the outer stator core (11); an outer stator core lower support (44) is fixed on the support bottom plate (41) to fix the lower end of the outer stator core (11); a low-temperature container support (40) is fixed on the support plate vertical plate (42) to accommodate the low-temperature container (3); at the same time, the low-temperature container support (40) is fixed with the low-temperature container (3), and a center through hole is arranged between the low-temperature container support (40) and the low-temperature container (3), so that the salient poles (21) and the pole shoes (22) of the inner stator core pass through the center through hole and are fixed at the ends; one superconducting coil device (5) is placed in each low-temperature container (3), and is filled with low-temperature coolant; the low-temperature container (3) comprises an open low-temperature container (31) and a closed low-temperature container (32); the low-temperature container support (40) comprises upper and lower low-temperature container supports (45) and inclined low-temperature container supports (46); the upper and lower low-temperature container supports (45) accommodate the open low-temperature container (31), and the inclined low-temperature container supports (46) accommodate the closed low-temperature container (32); the open low-temperature container (31) is a back-shaped structure container without a top, into which low-temperature coolant is directly injected and the liquid level can be controlled; the closed low-temperature container (32) is a fully closed back-shaped structure container, and the low-temperature coolant is injected through a coolant delivery pipe.

2. The background magnetic field simulation and testing device for superconducting coil quench detection and electromagnetic characteristic analysis of an electric machine according to claim 1, characterized in that, the open low-temperature container (31) is a back-shaped structure container with a center through hole, the inner circle bottom surface of which is provided with a through center through hole, and the outer circle bottom surface is a closed surface; one superconducting coil device (5) is fixedly placed in the back-shaped cavity of the open low-temperature container (31); the inner stator core salient poles (21) and the pole shoes (22) penetrate the center through hole, so that the magnetic flux generated by the energization of the outer stator armature winding is guided and concentrated through the superconducting coil by the inner stator core pole shoes (22) and the inner stator core salient poles (21), and an induced voltage is generated inside the coil.

3. The background magnetic field simulation and testing device for detecting quench of superconducting coils of electric machines and analyzing electromagnetic characteristics according to claim 1 or 2, characterized in that, the closed low-temperature container (32) comprises a container main body (321), a container cover (322), and a pipeline assembly (323). The container body (321) is arranged based on the structure of the open cryogenic container (31), and is provided with openings on the outer wall body for cooling liquid medium access and component installation; The container cover (322) covers and is fixed on the back-shaped cavity opening of the container body (321), forming a closed sealing structure; The pipeline assembly (323) includes a cooling liquid delivery pipe (3231) and an electrical lead pipe (3232), and is installed at the opening of the container body (321).

4. The background magnetic field simulation and testing device for superconducting coil quench detection and electromagnetic characteristic analysis of electric machines according to claim 1, characterized in that, The superconducting coil device (5) includes a superconducting coil (51) and a support frame; The superconducting coil (51) is suspended in the cryogenic container (3) through the support frame, and a gap is maintained between the superconducting coil (51) and the container wall to achieve non-contact fixation.

5. The background magnetic field simulation and testing device for superconducting coil quench detection and electromagnetic characteristic analysis of electric machines according to claim 1, characterized in that, The outer stator core (11) and the inner stator core (2) are made by laminating silicon steel sheets.

6. The background magnetic field simulation and testing device for detecting quench of superconducting coils of electric machines and analyzing electromagnetic characteristics according to claim 4, characterized in that, The superconducting coil is provided with voltage leads and current leads; The voltage leads are connected to a high-precision nanovolt meter (8) for measuring the terminal voltage of the superconducting coil; The current leads are connected to a direct current power supply (7) for providing direct current to the superconducting coil.

7. The background magnetic field simulation and testing device for detecting quench of superconducting coils of electric machines and analyzing electromagnetic characteristics according to claim 1, characterized in that, The device further includes an armature winding power supply system (6); The armature winding power supply system (6) is connected to the armature winding of the outer stator (1) for providing multi-phase alternating current to the armature winding.

8. The background magnetic field simulation and testing device for detecting quench of superconducting coils of electric machines and analyzing electromagnetic characteristics according to claim 7, characterized in that, The armature winding power supply system (6) adopts a programmable alternating current source or an inverter combined with a direct current power supply, and the amplitude and frequency of the output alternating current can be adjusted. The armature winding power supply system (6) is directly connected to the multi-phase output terminals of the armature winding, and by adjusting the amplitude and frequency parameters of the output current, different background magnetic field environments can be simulated.

9. The background magnetic field simulation and testing device for superconducting coil quench detection and electromagnetic characteristic analysis of electric machines according to claim 1, characterized in that, The air gap between the outer stator core (11) and the inner stator core (2) is in a uniform or non-uniform state. The uniform air gap is used to simulate the standard symmetric background magnetic field under normal operating conditions of the motor, and the non-uniform air gap is used to simulate the asymmetric background magnetic field presented under non-ideal operating conditions of the motor. By precisely controlling the thickness and installation position of the non-magnetic pad, the thickness of the air gap can be precisely adjusted.

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