Superconducting excitation device and superconducting motor

Abstract

The present invention discloses a superconducting excitation device and a superconducting motor, which belong to the technical field of superconducting excitation. The superconducting excitation device comprises an outer cryogenic container, a magnetic flux guiding barrier, an inner cryogenic container and a single-cake superconducting coil. N inner cryogenic containers are arranged inside the outer cryogenic container, and a single-cake superconducting coil is placed in each inner cryogenic container. The outer cryogenic container and the inner cryogenic container are isolated by a vacuum region. A circulating coolant is provided in each inner cryogenic container, and the single-cake superconducting coil is completely immersed in the coolant, and reaches the working temperature through the circulation of the coolant. The magnetic flux guiding barrier is located in the vacuum region between the outer cryogenic container and the inner cryogenic container, and the magnetic flux guiding barrier and the inner cryogenic container where the single-cake superconducting coil is placed are evenly and alternately arranged. The present invention can reduce the refrigeration power required for the normal operation of the coil, improve the overall efficiency of the device, and minimize the overall loss of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting excitation, and in particular to a superconducting excitation device and a superconducting motor. Background Art

[0002] In recent years, in order to solve the global energy shortage and alleviate environmental degradation, research and application in the field of new energy have received widespread attention. As a representative of new energy technology, wind power generation has become an important means to solve the energy crisis due to its clean and renewable characteristics. However, with the continuous expansion of the capacity of wind turbines, the size and weight of traditional permanent magnet motors have also increased, and it has gradually become difficult to meet actual needs. In contrast, superconducting motors have shown broad application prospects in the field of wind power generation due to their advantages of high power density and high efficiency.

[0003] Superconducting materials are often used in the excitation system of motors. Although they have very little loss when transmitting DC current, the alternating magnetic field generated by the armature reaction during the operation of the motor will cause AC losses in the superconductor. In addition, in order to improve the mechanical properties of the coil, the superconducting coil is usually designed as a double-pancake or even multi-pancake structure. This multi-pancake structure will produce more AC losses than a single-pancake coil with the same number of turns due to the mutual coupling of the magnetic fields between multiple coils. If effective measures are not taken to suppress these losses, the burden on the coil cooling system will be greatly increased, affecting the efficiency of the motor. More seriously, in the case of insufficient cooling power, the heat accumulation generated by the loss may cause the superconducting coil to quench or even be damaged.

[0004] At present, common methods for suppressing AC loss of superconducting coils include setting a copper shielding layer and a magnetic conductive block around the coil. Although these methods can reduce AC loss to a certain extent, the eddy current loss induced by them will increase the burden of coil cooling. Moreover, when these methods suppress the AC loss of multi-pancake superconducting coils, their shielding effect is often reduced due to the complex interaction of magnetic fields. Therefore, it is necessary to provide a reasonable design scheme for superconducting excitation devices to solve current technical problems, reduce the overall loss of the device, and reduce the power consumption of the refrigeration system. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a superconducting excitation device and a superconducting motor which can reduce the refrigeration power required for the normal operation of the coil, improve the overall efficiency of the device, and minimize the overall loss of the system.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In one aspect, a superconducting excitation device is provided, comprising an outer cryogenic container, a magnetic flux guiding barrier, an inner cryogenic container and a single-pancake superconducting coil, wherein:

[0008] The outer cryogenic container is the outer shell of the superconducting excitation device. The inner cryogenic container is provided with n inner cryogenic containers, where n is an integer greater than or equal to 2. One single-pancake superconducting coil is placed in each inner cryogenic container. The outer cryogenic container and the inner cryogenic container are isolated by a vacuum region.

[0009] Each of the inner low-temperature containers is provided with a circulating coolant, and the single-cake superconducting coil is completely immersed in the coolant, and reaches the working temperature through the circulation of the coolant;

[0010] The magnetic flux guiding barriers are located in a vacuum region between the outer cryogenic container and the inner cryogenic container, and the magnetic flux guiding barriers and the inner cryogenic container where the single-pancake superconducting coil is placed are evenly alternately arranged.

[0011] Furthermore, the number of turns of each of the single-disc superconducting coils is designed to be the same or different, and these single-disc superconducting coils are excited together to form an integrated superconducting excitation coil;

[0012] And / or, the single-cake superconducting coil is fixed in the inner cryogenic container via a coil support.

[0013] Furthermore, the number of the flux guiding barriers is determined to be n+1 according to the number of the single-cake superconducting coils, so as to ensure that the flux guiding barriers are provided on both sides of each single-cake superconducting coil.

[0014] Furthermore, the flux guiding barrier is designed to be flat in shape.

[0015] Furthermore, the thickness and width of each of the magnetic flux guiding barriers are the same or different, and the specific dimensions of the magnetic flux guiding barriers at different positions are determined according to the distance between the magnetic field source and the space margin between the inner and outer cryogenic containers.

[0016] Furthermore, the flux guiding barrier is made of a strong ferromagnetic material;

[0017] And / or, the flux guiding barrier is fixed by a thermally conductive bracket connected to the outer cryogenic container.

[0018] Furthermore, the inner cryogenic container is fixed in the outer cryogenic container by a heat-insulating bracket.

[0019] Furthermore, the superconducting excitation device is shaped as a circle or a racetrack as a whole.

[0020] On the other hand, a superconducting motor is provided, which comprises, from inside to outside, an inner stator core, a rotor and an outer stator, wherein the outer stator is provided with an armature winding, and the inner stator core is provided with the above-mentioned superconducting excitation device.

[0021] Furthermore, the number of superconducting excitation devices installed in the superconducting motor is determined according to the number of motor pole pairs.

[0022] The present invention has the following beneficial effects:

[0023] The superconducting excitation device and superconducting motor of the present invention utilize a method of evenly alternating arrangement of flux guiding barriers and single-disc superconducting coils to effectively guide the magnetic field around the coils and isolate the magnetic field coupling between multiple single-disc superconducting coils, thereby significantly reducing the AC loss of the entire superconducting excitation coil, thereby reducing the cooling power required for superconducting coil excitation, improving the overall efficiency of the device, and minimizing the overall loss of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a low-power consumption superconducting excitation device using alternately distributed flux guide barriers and single-pancake superconducting coils according to an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of the structure of a fixed bracket used in a low-power superconducting excitation device using a magnetic flux guide barrier and a single-pancake superconducting coil alternately arranged according to an embodiment of the present invention, wherein (a) is a structural diagram of the coil bracket, (b) is a structural diagram of the heat-conducting bracket of the magnetic flux guide barrier, and (c) is a structural diagram of the insulation bracket of the inner low-temperature container;

[0026] Figure 3 A schematic diagram of the structure of a double-stator high-temperature superconducting motor, which is an application object of an embodiment of the present invention;

[0027] Figure 4 A three-dimensional exploded view of a racetrack-shaped superconducting excitation device applied to a double-stator high-temperature superconducting motor according to an embodiment of the present invention;

[0028] Figure 5 Schematic diagram of the working principle of the flux guiding barrier of an embodiment of the present invention, wherein (a) is a magnetic field distribution diagram in a conventional double-pancake structure device without the flux guiding barrier installed, and (b) is a magnetic field distribution diagram in the device when the flux guiding barrier and two single-pancake superconducting coils are alternately arranged;

[0029] Figure 6 The figures are effect diagrams of reducing AC losses of a low-power superconducting excitation device using an alternating distribution of flux-guiding barriers and single-pancake superconducting coils according to an embodiment of the present invention, wherein (a) is a comparison diagram of the AC losses generated by a conventional double-pancake structure without a flux-guiding barrier installed during normal operation of the motor and the alternating distributed structure of the present invention, and (b) is a comparison diagram of the AC losses generated by a conventional double-pancake structure without a flux-guiding barrier installed when a three-phase short circuit occurs in the motor and the alternating distributed structure of the present invention.

[0030] In the above drawings: 1-external cryogenic container, 2-flux guiding barrier, 3-inner cryogenic container, 4-single-cake superconducting coil, 5-vacuum area, 6-cooling liquid, 7-separation distance of single-cake superconducting coil, 8-thickness of flux guiding barrier, 9-width of flux guiding barrier, 10-coil bracket, 11-thermal conductive bracket of flux guiding barrier, 12-insulating bracket of inner cryogenic container, 13-superconducting excitation device, 14-inner stator of superconducting motor, 15-rotor of superconducting motor, 16-outer stator of superconducting motor, 17-armature winding, 18-magnetic lines of force. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0032] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0033] On the one hand, the present invention provides a superconducting excitation device (a low-power consumption type using a magnetic flux guide barrier and a single-pancake superconducting coil alternately distributed) such as Figure 1 As shown, it includes an outer cryogenic container 1, a magnetic flux guiding barrier 2, an inner cryogenic container 3, and a single-cake superconducting coil 4, wherein:

[0034] The outer cryogenic container 1 is the outer shell of the superconducting excitation device. n inner cryogenic containers 3 are arranged inside the outer cryogenic container 1, where n is an integer greater than or equal to 2. A single-pancake superconducting coil 4 is placed in each inner cryogenic container 3. The outer cryogenic container 1 and the inner cryogenic container 3 are isolated by a vacuum region 5, that is, the vacuum region 5 is set between the outer cryogenic container 1 and the inner cryogenic container 3, which can eliminate the convection and heat conduction of gas molecules and effectively isolate the heat exchange between the inner cryogenic container 3 and the external environment;

[0035] Each inner cryogenic container 3 is provided with a circulating coolant 6 (such as liquid nitrogen or liquid helium), and the single-cake superconducting coil 4 is completely immersed in the coolant 6, and reaches the working temperature through the circulation of the coolant 6. Specifically, the coolant 6 circulates in the inner cryogenic container 3 and directly contacts the single-cake superconducting coil 4. The coolant 6 quickly conducts and takes away the heat generated by the single-cake superconducting coil 4 through its high thermal conductivity, thereby ensuring that the single-cake superconducting coil 4 is always kept at the required low temperature state, ensuring the efficient operation of the device;

[0036] The number of turns of each single-cake superconducting coil 4 can be designed to be the same or different. These single-cake superconducting coils 4 are excited together to form an integral superconducting excitation coil. In the embodiment shown in the figure, the superconducting excitation coil adopts a double-cake structure with the same number of turns, which can improve its mechanical strength and stability. In addition, a certain distance 7 is maintained between the two single-cake superconducting coils 4 and they are placed in two independent inner cryogenic containers 3 respectively. The separation distance 7 can be flexibly set as needed, which can be specifically determined by the space inside the outer cryogenic container 1. Such a design can reduce the magnetic field coupling between the two single-cake superconducting coils 4 and reduce the AC loss generated by the single-cake superconducting coils 4 to a certain extent.

[0037] The magnetic flux guiding barrier 2 is located in the vacuum region 5 between the outer cryogenic container 1 and the inner cryogenic container 3 , and the magnetic flux guiding barrier 2 and the inner cryogenic container 3 in which the single-cake superconducting coil 4 is placed are evenly and alternately arranged.

[0038] The superconducting excitation device of the present invention utilizes the method of evenly alternating the arrangement of flux guiding barriers and single-disk superconducting coils to effectively guide the magnetic field around the coils and isolate the magnetic field coupling between multiple single-disk superconducting coils, thereby significantly reducing the AC loss of the entire superconducting excitation coil, thereby reducing the cooling power required for superconducting coil excitation, improving the overall efficiency of the device, and minimizing the overall loss of the system.

[0039] The support structure used to fix the superconducting excitation device, such as Figure 2 As shown, the support structure may include Figure 2 The coil support 10 shown in (a) Figure 2 The heat conducting bracket 11 shown in (b) and Figure 2 The insulating bracket 12 is shown in (c). The single-cake superconducting coil 4 can be fixed in the inner cryogenic container 3 by the coil bracket 10. The magnetic flux guiding barrier 2 can be fixed by a thermally conductive bracket 11 connected to the outer cryogenic container 1. Specifically, the thermally conductive bracket 11 is connected to the outer cryogenic container 1 but not in contact with the inner cryogenic container 3, so that all the heat generated by the magnetic flux guiding barrier 2 is transferred to the outer cryogenic container through the thermally conductive bracket 11. The inner cryogenic container 3 can be fixed in the outer cryogenic container 1 by the insulating bracket 12 to prevent the heat from the external environment from being transferred to the inner cryogenic container 3. The arrangement of the thermally conductive bracket 11 and the insulating bracket 12 in this embodiment allows all the heat generated by the magnetic flux guiding barrier 2 to be transferred to the external environment through the thermally conductive bracket 11, effectively preventing the heat from the magnetic flux guiding barrier 2 and the external environment from adding additional heat burden to the refrigeration system.

[0040] In this embodiment, the number of flux guiding barriers 2 can be arranged in total of 3 according to the number of single-cake superconducting coils 4, and they are alternately distributed with the inner cryogenic container 3 to ensure that both sides of each single-cake superconducting coil 4 are provided with flux guiding barriers 2. The flux guiding barrier 2 can be designed to be flat and placed in the vacuum area 5 between the inner and outer cryogenic containers. The flux guiding barrier 2 can be made of a strong ferromagnetic material, and the flux guiding barrier 2 has a high magnetic permeability and can effectively guide and shield the magnetic flux. At present, most of the superconducting materials used are in the shape of strips with a high aspect ratio. Due to their anisotropic magnetic field dependence, the magnetic field perpendicular to the wide surface of the strip has a more obvious penetration effect on the strip. Therefore, the vertical magnetic field is the main source of AC loss generated by the superconducting coil. The present invention can effectively convert the vertical magnetic field around the single-cake superconducting coil 4 into a parallel magnetic field by alternately arranging the flux guiding barriers 2 around the two single-cake superconducting coils 4, and the flux guiding barrier 2 between the two single-cake superconducting coils 4 can also effectively absorb the self-field generated by the two coils, thereby reducing the mutual coupling of the self-field between the two single-cake superconducting coils 4.

[0041] The working principle of the magnetic flux guide barrier 2 is as follows Figure 5 As shown, (a) is the magnetic field distribution diagram in the device when no flux guide barrier is installed around the double-cake superconducting coil; (b) is the magnetic field distribution diagram in the device when the flux guide barrier and two single-cake superconducting coils are alternately distributed. It can be seen that the setting of the flux guide barrier 2 changes the path of the original magnetic lines of force 18, and most of the magnetic lines of force 18 pass through the flux guide barrier 2. The magnetic field around the single-cake superconducting coil 4 changes from a ring shape to a nearly vertical direction (parallel magnetic field), and the contribution of the parallel magnetic field to the AC loss is extremely small. Therefore, the AC loss generated by the single-cake superconducting coil 4 is effectively reduced, thereby reducing the cooling power required for cooling the coil.

[0042] The thickness 8 and width 9 of the flux guide barrier 2 can be determined by the distance between it and the magnetic field source and the space margin between the inner and outer cryogenic containers. When there is enough space, the greater the thickness 8 and width 9 of the flux guide barrier 2, the better the shielding effect; when there is insufficient space, the thickness 8 and width 9 of the flux guide barrier 2 near the magnetic field source can be appropriately increased, so that the thickness 8 and width 9 of the flux guide barrier 2 decrease as the distance from the magnetic field source increases. In the embodiment shown in the figure, three flux guide barriers 2 of the same size are used, which can achieve a good effect.

[0043] In another aspect, the present invention provides a superconducting motor, such as Figure 3 As shown, from inside to outside, it includes an inner stator core 14, a rotor 15 and an outer stator 16, the outer stator 16 is provided with an armature winding 17, and the inner stator core 14 is provided with the above-mentioned superconducting excitation device. The superconducting excitation device of the superconducting motor adopts a racetrack-shaped structure, and its three-dimensional overall structure is as shown in FIG. Figure 4 shown.

[0044] The superconducting motor of the present invention utilizes the method of evenly alternating the arrangement of flux guiding barriers and single-disk superconducting coils to effectively guide the magnetic field around the coil and isolate the magnetic field coupling between multiple single-disk superconducting coils, thereby significantly reducing the AC loss of the overall superconducting excitation coil, thereby reducing the cooling power required for superconducting coil excitation, improving the overall efficiency of the device, and minimizing the overall loss of the system.

[0045] Specifically, in this embodiment, the above-mentioned superconducting excitation device is used for the excitation of a superconducting motor. The structure of the superconducting motor is as follows: Figure 3 As shown, the superconducting motor has 4 pairs (8) of poles, so 8 superconducting excitation devices 13 are used. In this way, the rated excitation current is passed through each single-disc superconducting coil 4. Due to the zero resistance characteristic of the superconductor, a stable and strong excitation magnetic field can be generated on the inner stator core 14. When the rotor 15 rotates at the rated speed, the excitation magnetic field changes in size and direction through the modulation of the rotor 15. This changing magnetic field will induce an electromotive force on the armature winding 17 of the outer stator 16, and finally the motor works normally and outputs the induced voltage to the load.

[0046] When the motor is working normally, the AC loss generated by the superconducting excitation device of the present invention is compared with the AC loss generated by the traditional double-pancake coil. Figure 6 As shown in (a); when a three-phase fault short circuit occurs in the motor, the AC loss generated by the superconducting excitation device of the present invention is compared with the AC loss generated by the traditional double-pancake coil. Figure 6 As shown in (b). It can be seen that the superconducting excitation device of the present invention generates very little loss during normal operation, which can significantly reduce the power consumption of the refrigeration system and improve the overall efficiency of the device; when the motor fails and short-circuits, the device can also avoid the pressure on the refrigeration system caused by the sudden increase in loss heat.

[0047] In summary, the present invention effectively shields the interference of the external magnetic field and the coupled magnetic field between multiple single-cake superconducting coils through the reasonable layout of the flux guiding barrier and the single-cake superconducting coil, reduces the AC loss of the superconducting coil, and the flux guiding barrier is arranged in the vacuum area between the inner and outer cryogenic containers, and the heat generated by the eddy current of the flux guiding barrier is effectively conducted to the outer cryogenic container through the heat-conducting bracket, and the loss generated by the flux guiding barrier itself will not be conducted to the inner cryogenic container, avoiding additional heat burden on the coolant in the inner cryogenic container, further improving the cooling efficiency and overall performance of the device, thereby reducing the refrigeration power required for the operation of the device.

[0048] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A superconducting excitation device, characterized in that: It comprises an outer cryogenic container (1), a magnetic flux guiding barrier (2), an inner cryogenic container (3) and a single-pancake superconducting coil (4), wherein: The outer cryogenic container (1) is the outer shell of the superconducting excitation device. n inner cryogenic containers (3) are arranged inside the outer cryogenic container (1), where n is an integer greater than or equal to 2. One single-pancake superconducting coil (4) is placed in each inner cryogenic container (3). The outer cryogenic container (1) and the inner cryogenic container (3) are separated by a vacuum region (5). Each of the inner low-temperature containers (3) is provided with a circulating cooling liquid (6), and the single-cake superconducting coil (4) is completely immersed in the cooling liquid (6) and reaches the working temperature through the circulation of the cooling liquid (6); The magnetic flux guiding barrier (2) is located in a vacuum region (5) between the outer cryogenic container (1) and the inner cryogenic container (3), and the magnetic flux guiding barrier (2) and the inner cryogenic container (3) in which the single-pancake superconducting coil (4) is placed are evenly and alternately arranged; The magnetic flux guiding barrier (2) is made of a strong ferromagnetic material; and / or, the magnetic flux guiding barrier (2) is fixed by a heat-conducting bracket (11) connected to the outer cryogenic container (1); The number of the magnetic flux guiding barriers (2) is determined to be n+1 according to the number of the single-pancake superconducting coils (4), so as to ensure that the magnetic flux guiding barriers (2) are provided on both sides of each single-pancake superconducting coil (4).

2. The superconducting excitation device according to claim 1, characterized in that: The number of turns of each single-disc superconducting coil (4) is designed to be the same or different, and these single-disc superconducting coils (4) are excited together to form an integrated superconducting excitation coil; And / or, the single-cake superconducting coil (4) is fixed in the inner low-temperature container (3) via a coil support (10).

3. The superconducting excitation device according to claim 1, characterized in that: The magnetic flux guiding barrier (2) is designed to be flat in shape.

4. The superconducting excitation device according to claim 1, characterized in that: The thickness and width of each magnetic flux guiding barrier (2) are the same or different, and the specific size of the magnetic flux guiding barrier (2) at different positions is determined according to the distance between the magnetic field source and the space margin between the inner and outer cryogenic containers.

5. The superconducting excitation device according to claim 1, characterized in that: The inner low-temperature container (3) is fixed in the outer low-temperature container (1) by a heat-insulating bracket (12).

6. The superconducting excitation device according to claim 1, characterized in that: The superconducting excitation device is in a circular or racetrack shape as a whole.

7. A superconducting motor, comprising, from inside to outside, an inner stator core (14), a rotor (15) and an outer stator (16), wherein the outer stator (16) is provided with an armature winding (17), characterized in that: The inner stator core (14) is provided with a superconducting excitation device as claimed in any one of claims 1 to 6.

8. The superconducting motor according to claim 7, characterized in that: The number of superconducting excitation devices installed in the superconducting motor is determined according to the number of motor pole pairs.

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