Excitation system of high-temperature superconducting synchronous motor with multiple superconducting coils and rotating pole shoes

Abstract

The present invention discloses a multi-superconducting coil rotating pole shoe type high temperature superconducting synchronous motor excitation system in the field of superconducting motor technology, comprising: an inner stator core, the inner stator core is a cylindrical structure with a hollow axis; multiple groups of Dewar systems with built-in superconducting coils, symmetrically mounted on the outer wall of the inner stator core; multiple groups of rotor cores that can rotate along the axial direction of the inner stator core, symmetrically distributed axially around the inner stator core and the Dewar system, and a second air gap for the magnetic field to pass through exists between the rotor core and the inner stator core. The present invention can evenly divide the magnetic circuit into multiple parts along the axial direction, reduce the distance of the axial magnetic circuit of the single-loop magnetic field, make the axial magnetic field distribution more uniform, thereby reducing axial magnetic leakage; avoid the rotor cantilever being too long, making the rotor structure more solid; can further realize multiple groups of coil structures, avoid the axial length limitation of the rotating pole shoe type superconducting motor, have higher motor efficiency and power density, and be more suitable for high speed and high vibration fields.

Description

Technical Field

[0001] The invention relates to a multi-superconducting coil rotating pole shoe type high-temperature superconducting synchronous motor excitation system, belonging to the technical field of superconducting motors. Background Art

[0002] Superconducting motor is a kind of high power density motor, which has important application scenarios in the fields of ship propulsion, wind power generation, and aerospace. In recent years, the performance of superconducting materials has been continuously improved, and the price has gradually decreased, making the application technology of superconducting motors widely concerned. The rotating pole shoe high temperature superconducting motor, as published in the patent (CN 109639103B), is a motor that uses superconducting coil excitation to form a rotating magnetic field by rotating the rotor core. Compared with conventional motors, the superconducting coils in this type of motor are in a stationary state, eliminating the use of complex structures such as rotating dewars, dynamic seals, and brush systems, improving the reliability of superconducting motors and reducing manufacturing costs. At the same time, the rotating parts of this type of motor are only composed of the rotor core, which has the characteristics of strong structure and small moment of inertia. It is particularly suitable for use in high-speed, high-vibration and other motor demand fields, and has good application prospects.

[0003] In a rotating pole shoe type high temperature superconducting motor, the magnetic field is generated by the superconducting coil, which is conducted to the rotor core through the inner stator end, then conducted to the inside of the motor along the rotor core, and radially conducted to the outer stator core through the first air gap, thereby cutting the armature winding. The magnetic field distribution has both axial and radial distribution properties, and as the axial length of the motor increases, the magnetic flux conducted in the rotor core decreases, resulting in a decrease in the magnetic flux in the outer stator core, resulting in a waste of the outer stator core. In addition, the rotor core forms a cantilever structure, which affects the mechanical strength of the rotor core. Summary of the invention

[0004] The object of the present invention is to overcome the deficiencies in the prior art and provide a multi-superconducting coil rotating pole shoe type high-temperature superconducting synchronous motor excitation system, which can evenly divide the magnetic circuit into multiple parts along the axial direction, reduce the distance of the axial magnetic circuit of a single-loop magnetic field, make the axial magnetic field distribution more uniform, and thus reduce the effect of axial magnetic leakage.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] The present invention provides a multi-superconducting coil rotating pole shoe type high temperature superconducting synchronous motor excitation system, comprising:

[0007] An inner stator core, wherein the inner stator core is a cylindrical structure with a hollow axis;

[0008] Multiple sets of Dewar systems with built-in superconducting coils are symmetrically mounted on the outer wall of the inner stator core;

[0009] A plurality of groups of rotor cores rotatable along the axial direction of the inner stator core are axially symmetrically distributed around the inner stator core and the Dewar system, and a second air gap for the magnetic field to pass through exists between the rotor core and the inner stator core.

[0010] Furthermore, the number of the Dewar systems is N, the circumferential outer wall of the inner stator core is symmetrically provided with N+1 annular bosses, and each Dewar system is sleeved in the recess between adjacent annular bosses.

[0011] Furthermore, the Dewar system is a double-layer thin-wall insulation structure in the shape of a "U" character, and the interior of the Dewar system is filled with liquid nitrogen, and a magnetic shielding structure is arranged on the outer wall of the Dewar system.

[0012] Furthermore, the superconducting coil is wound from superconducting wire or tape.

[0013] Furthermore, the rotor core includes a C-shaped rotor core and an I-shaped rotor core, and the C-shaped rotor core and the I-shaped rotor core are alternately arranged along the circumferential direction of the inner stator core.

[0014] Furthermore, the C-shaped rotor core, the ∘-shaped rotor core and the inner stator core are all made of high magnetic permeability materials, and the high magnetic permeability materials include cold-rolled silicon steel, soft magnetic composite materials or amorphous alloy materials.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] Compared with a single superconducting coil structure, the multi-superconducting coil rotating pole shoe type high-temperature superconducting synchronous motor excitation system proposed in the present invention divides the magnetic circuit into multiple parts along the axial direction, thereby reducing the distance of the axial magnetic circuit of a single-loop magnetic field, making the axial magnetic field distribution more uniform, thereby reducing axial magnetic leakage; avoiding excessive length of the rotor cantilever, making the rotor structure more robust; and further realizing a multi-group coil structure, avoiding the axial length limitation of the rotating pole shoe type superconducting motor, having higher motor efficiency and power density, and being more suitable for high-speed and high-vibration fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the excitation system 3 / 4 and the magnetic circuit direction of the rotating pole shoe type high temperature superconducting synchronous motor provided by an embodiment of the present invention;

[0018] Figure 2 is a structural diagram of a C-shaped rotor core provided by an embodiment of the present invention;

[0019] Figure 3 is a structural diagram of a radial rotor core provided by an embodiment of the present invention;

[0020] Figure 4 It is a structural diagram of the inner stator core provided in an embodiment of the present invention.

[0021] In the figure: 1. C-shaped rotor core; 2. BU-shaped rotor core; 3. Dewar system; 4. Superconducting coil; 31. Left Dewar system; 32. Right Dewar system; 41. Left superconducting coil; 42. Right superconducting coil; 5. Inner stator core; 6. Second air gap. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0023] Example:

[0024] Multi-superconducting coil rotating pole shoe high temperature superconducting synchronous motor excitation system, please refer to Figure 1 , including a coaxially arranged rotor core, an inner stator core 5, two groups of superconducting coils 4 and their Dewar system 3, wherein the rotor core includes a C-shaped rotor core 1 and a B-shaped rotor core 2, the Dewar system 3 includes a left Dewar system 31 and a right Dewar system 32, and the two groups of superconducting coils 4 include a left superconducting coil 41 and a right superconducting coil 42; there is a second air gap 6 between the C-shaped rotor core 1 and the B-shaped rotor core 2 and the inner stator core 5; the left superconducting coil 41 is arranged in the left Dewar system 31, the right superconducting coil 42 is arranged in the right Dewar system 32, and the two groups of superconducting coils 4 and their Dewar system 3 are mounted on both sides of the inner stator core 5.

[0025] It should be noted that the C-shaped rotor core 1 and the I-shaped rotor core 2 are arranged alternately in the circumferential direction to form the N pole and S pole of the rotating pole shoe type superconducting motor excitation system, and the number is determined by the number of pole pairs of the designed motor; the left superconducting coil 41 and the right superconducting coil 42 are both circular structures with equal number of turns. When the motor is running, a direct current of equal magnitude and opposite direction is passed through to form an S pole at both ends of the inner stator core 5 and an N pole in the middle; the inner stator core 5 is placed on the innermost side and is a hollow cylindrical structure, and there are cylindrical bosses at both ends and the center of the cylinder, wherein the hollow cylinder is used as Access channel for liquid nitrogen and wires; the left Dewar system 31 and the right Dewar system 32 have the same structure, which is a double-layer insulation structure with liquid nitrogen inside, which can provide a low-temperature environment for the operation of the superconducting coil 4; the outer wall of the Dewar system 3 is provided with a magnetic shielding structure to shield the alternating magnetic field and ensure the magnetic field environment for the operation of the superconducting coil 4; the C-shaped rotor core 1, the BO-shaped rotor core 2 and the inner stator core 5 are made of high magnetic permeability materials such as cold-rolled silicon steel, soft magnetic composite materials or amorphous alloys to provide a high magnetic permeability magnetic circuit; the left superconducting coil 41 and the right superconducting coil 42 are wound by superconducting wires or strips.

[0026] When the rotating pole shoe type high temperature superconducting motor is operating normally, the two groups of superconducting coils 4 are respectively placed in their Dewar system 3 to ensure the low temperature environment and electromagnetic environment for the operation of the superconducting coils 4. Excitation currents of equal magnitude and opposite directions are respectively passed into the left superconducting coil 41 and the right superconducting coil 42. In this way, the magnetic flux generated by the two groups of superconducting coils 4 is equal in magnitude and opposite in direction, forming two parts of the magnetic field, which respectively enter the C-shaped rotor core 2 through the second air gap 6 along the middle of the inner stator core 5 to form an N-pole magnetic field, and after passing through the motor stator and armature winding, return to the C-shaped rotor core 1 to form an S-pole magnetic field, and further return to the inner stator core 5 through the second air gap 6 to form a closed magnetic circuit. When the current directions are opposite, magnetic circuits in opposite directions can be formed. The principle is the same. When more than two groups of superconducting coils 4 are used, it is sufficient to ensure that the current passing directions of adjacent superconducting coils 4 are opposite. In this way, magnetic poles with staggered N poles and S poles of the excitation system are formed. Figure 1 A direction of magnetic circuit distribution is given in . It can be seen that compared with the single superconducting coil 4 structure, the excitation system of the double coil structure divides the magnetic circuit into two parts along the axial direction, reducing the distance of the axial magnetic circuit of the single-loop magnetic field, and the axial magnetic field distribution is more uniform, thereby reducing axial magnetic leakage; avoiding the rotor cantilever being too long, making the rotor structure more robust; and further realizing multiple sets of coil structures, avoiding the axial length limitation of the rotating pole shoe superconducting motor.

[0027] When the motor is operating normally, the rotating parts are only the C-shaped rotor core 1 and the 1-shaped rotor core 2, and other parts such as the inner stator core 5, the left and right Dewar systems 31 and 32, the left superconducting coil 41 and the right superconducting coil 42, and the cryogenic medium in the Dewar system 3 are all in a stationary state. The excitation current in the left and right superconducting coils 41 and 42 and the liquid nitrogen in the left and right Dewar systems 31 and 32 for ensuring the low temperature environment of the superconducting coils 4 can be introduced through the hollow shaft of the inner stator core 5, avoiding the use of rotating dynamic seals and brush systems.

[0028] The entire multi-superconducting coil rotating pole shoe type high temperature superconducting synchronous motor excitation system is placed in the motor stator cavity. Through the rotation of the S-pole and N-pole magnetic fields formed by the C-shaped rotor core 1 and the 1-shaped rotor core 2, a rotating magnetic motive force is formed in the stator cavity, cutting the armature winding to convert mechanical energy into electrical energy. By passing a three-phase alternating current through the armature, a rotating magnetic field is formed in the stator cavity, driving the C-shaped rotor core 1 and the 1-shaped rotor core 2 that form the S-pole and N-pole magnetic fields to rotate, the electrical energy is converted into mechanical energy.

[0029] It can be seen that the rotor core structure is very simple and strong. The rotating pole shoe type high temperature superconducting synchronous motor based on this structural excitation system has the characteristics of reliable low temperature protection, high structural strength and high power density, and is expected to be used in aerospace, armored vehicles and other fields requiring high speed and high power density motors.

[0030] The above is only 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 technical 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 multi-superconducting coil rotating pole shoe high temperature superconducting synchronous motor excitation system, characterized in that: include: An inner stator core, wherein the inner stator core is a cylindrical structure with a hollow axis; Multiple sets of Dewar systems with built-in superconducting coils are symmetrically mounted on the outer wall of the inner stator core; A plurality of groups of rotor cores rotatable along the axial direction of the inner stator core are axially symmetrically distributed around the inner stator core and the Dewar system, and a second air gap is provided between the rotor core and the inner stator core for the magnetic field to pass through; The number of the Dewar systems is N, and the outer circumferential wall of the inner stator core is symmetrically provided with N+1 annular bosses, and each Dewar system is mounted in a recess between adjacent annular bosses; The rotor core comprises a C-shaped rotor core and an I-shaped rotor core, and the C-shaped rotor core and the I-shaped rotor core are alternately arranged along the circumferential direction of the inner stator core.

2. The multi-superconducting coil rotating pole shoe type high temperature superconducting synchronous motor excitation system according to claim 1 is characterized in that: The Dewar system is a double-layer thin-wall insulation structure in the shape of a "U" character, and the interior of the Dewar system is filled with liquid nitrogen. A magnetic shielding structure is arranged on the outer wall of the Dewar system.

3. The multi-superconducting coil rotating pole shoe type high temperature superconducting synchronous motor excitation system according to claim 1 is characterized in that: The superconducting coil is formed by winding superconducting wire or tape.

4. The multi-superconducting coil rotating pole shoe type high temperature superconducting synchronous motor excitation system according to claim 1 is characterized in that: The C-shaped rotor core, the ∠-shaped rotor core and the inner stator core are all made of high magnetic permeability materials, and the high magnetic permeability materials include cold-rolled silicon steel, soft magnetic composite materials or amorphous alloy materials.

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