Annular winding superconducting motor with interelectrode damping coils

Abstract

The invention discloses an annular winding superconducting motor with an interelectrode damping coil, belongs to the technical field of motor design and superconducting motors, and particularly relates to a structure improvement method for reducing alternating current loss of a superconducting coil in a stator superconducting excitation motor. The stator iron core and the rotor iron core are both of a salient pole structure. The superconducting magnet is wound on a yoke portion of a large stator groove of the stator iron core in a striding mode to form an annular winding, a closed magnetic field loop is formed and used for establishing an excitation magnetic field, and the armature winding is wound on a stator tooth portion. The superconducting material has high critical current density, and the power density of the motor can be remarkably improved. A salient pole structure of a stator and a rotor enables a magnetic field in a large stator slot to change continuously when the motor runs at a high speed, so that a superconducting magnet generates alternating current loss. A damping coil is inserted into a large stator slot, and a reverse magnetic field generated by induced current of the damping coil is used for counteracting a variable magnetic field in the large stator slot, so that alternating current loss generated by a superconducting magnet is reduced.

Description

Technical Field

[0001] This invention relates to the fields of motor design and superconducting motor technology, and in particular to a toroidal winding superconducting motor with inter-pole damping coils. Background Technology

[0002] With the development of green energy and electric propulsion systems, traditional motor design and optimization methods are finding it increasingly difficult to improve the ultimate performance of motors. High-power-density motors utilizing high-temperature superconducting materials have become a crucial research direction in the aerospace, power, and military fields. Superconducting motors possess higher electrical or magnetic loads, offering advantages in high power density and high efficiency. The excitation coils of stator-excited superconducting motors are stationary, facilitating cooling system placement, and they exhibit excellent mechanical stability and electromagnetic symmetry, making them suitable for high-speed operation.

[0003] In toroidal winding stator superconducting motors, the superconducting excitation coil typically employs a double-disc racetrack structure, mounted on the stator to form a toroidal winding, through which a direct current is applied to generate the main magnetic flux. Because this coil is close to the stator teeth, and the armature winding is wound on the stator teeth, strong alternating magnetic flux is generated in the stator slot region when the armature winding carries alternating current and the rotor rotates at high speed. These disturbances couple to the area where the superconducting excitation coil is located, resulting in significant AC losses. These AC losses are closely related to the armature current frequency and amplitude, and are particularly severe in high-speed motors. They not only increase the thermal load on the superconducting cooling system and reduce system efficiency, but may also cause localized superconducting coil quenching, endangering the safe operation of the system.

[0004] Therefore, how to improve the toroidal winding stator superconducting motor to increase its power density while reducing the magnetic field generated by the armature winding and the impact of the high-speed rotation of the rotor on the superconducting coil, and preventing it from losing quench and generating excessive AC losses, has become a research topic. Summary of the Invention

[0005] The embodiments of the present invention provide a toroidal winding superconducting motor with inter-pole damping coils, which can effectively reduce the coupling effect of the armature winding magnetic field on the superconducting magnet while increasing the motor power density, and suppress electromagnetic disturbances generated in the superconducting region due to high-speed rotor operation, preventing local quenching failure and excessive AC loss of the superconducting coil.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] A toroidal winding superconducting motor with interpole damping coils, the main body of the toroidal winding superconducting motor includes: a stator core (1), a rotor core (2), an armature winding (3), a superconducting magnet (4), a support plate (5), and a damping coil (6); the stator core (1) and the rotor core (2) are both salient pole structures, the stator core (1) includes: a stator yoke (7) and stator teeth (8) arranged in sequence, the rotor core (2) includes: a rotor yoke (9) and rotor teeth (10) arranged in sequence; the armature winding (3) is wound on the stator teeth (8); the superconducting magnet (4) is installed at the gaps of the stator core (1), and at least 4 gaps are evenly distributed around the center on the stator core (1); a support plate (5) is installed on the stator yoke (7) at each gap, and the damping coil (6) is wound on the support plate (5).

[0008] The stator core (1) includes 12 stator teeth (8), which adopt a parallel tooth structure. This structure can generate four larger stator slot spaces, which facilitates the winding of more superconducting coils and armature coils. The rotor core (2) includes 8 rotor teeth (10), which are equally spaced along the axial direction of the rotor core (2). All rotor teeth (10) have the same structure to ensure the symmetry of the air gap magnetic field. Armature windings (3) are wound on four stator teeth (8) that are 90° apart in the circumferential direction, and then connected in series. In this scheme, only armature windings (3) are wound on the stator teeth. The armature windings (3) wound on the four stator teeth (8) that are 90° apart in space are connected in series to form a three-phase symmetrical armature winding.

[0009] The gap between adjacent stator teeth (8) serves as a stator slot, forming a total of four large stator slots and eight small stator slots; the superconducting magnet (4) is wound across the large stator slot of the stator yoke (7). The superconducting magnet (4) is wound across the stator yoke (7) of the large stator slot in the stator core (1) to form a ring winding structure, and the wound superconducting magnet (4) is divided into an outer stator yoke coil segment and an inner stator yoke coil segment according to the inner and outer spaces of the stator yoke (7). The current flowing through two adjacent superconducting magnets (4) has opposite directions, and the magnetic field polarities generated by the stator teeth (8) that are 90° apart in space are opposite, forming a closed magnetic circuit. In practical applications, the current flowing through two adjacent superconducting magnets (4) has opposite directions, and the magnetic field polarities generated by the stator teeth (8) that are 90° apart in space are opposite.

[0010] In the preferred embodiment, the support plate (5) is fixedly installed between two adjacent stator teeth (8) of the large stator slot, and the damping coil (6) is fixed in the support plate (5) with an embedded structure. Specifically, in the toroidal winding stator superconducting motor, the support plate (5) is fixedly installed between adjacent stator teeth of the large stator slot, and a copper strip is embedded in the support plate and fixed in the support plate as a damping coil (6). When the motor is running, the high-frequency magnetic field generated by the armature winding alternates in the stator slot region, the magnetic flux passing through the region between adjacent stator teeth of the large stator slot will induce a circulating current in the damping coil (6), and then form a reverse magnetic field in the local area. These reverse magnetic fields can suppress the disturbance magnetic flux in the structure, effectively weaken the dynamic fluctuation of the magnetic flux in the superconducting coil region, and significantly reduce the AC loss in the superconducting coil.

[0011] This invention provides a toroidal winding superconducting motor with interpole damping coils. Both the stator core (1) and rotor core (2) are salient-pole structures. The stator teeth (8) employ a parallel tooth structure, which generates a larger stator slot space, facilitating the winding of more superconducting coils and armature coils. Only armature windings (3) are wound on the stator teeth (8), and a superconducting magnet (4) is wound across the stator yoke (7) of the large stator slot in the stator core (1). A support liner (5) is fixedly installed between adjacent stator teeth in the large stator slot of the toroidal winding stator superconducting motor, and a copper strip is embedded in the support liner and fixed within it as a damping coil (6). This damping coil (6) is a closed-loop conductive circuit without external circuit connection, weakly coupled to the main magnetic flux, and is only used to counteract disturbances in the high-frequency magnetic field of the armature. When the motor runs at high speed, the damping coil (6) induces a current to form a reverse magnetic field, thereby weakening the original disturbance magnetic flux. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 A two-dimensional cross-sectional structural diagram of a toroidal winding superconducting motor with inter-electrode damping coil is provided for an embodiment of the present invention.

[0014] Figure 2 A schematic diagram of the connection between the copper coil and the excitation coil of a toroidal winding superconducting motor with inter-pole damping coil provided for an embodiment of the present invention;

[0015] Figure 3 A three-dimensional cross-sectional structural diagram of a toroidal winding superconducting motor with inter-electrode damping coil provided for an embodiment of the present invention;

[0016] Figure 4 A double-layer racetrack-shaped superconducting coil structure for a toroidal winding superconducting motor with inter-electrode damping coil is provided in this embodiment of the invention.

[0017] Figure 5 A three-dimensional cross-sectional structural diagram of a superconducting magnet for a toroidal winding superconducting motor with inter-electrode damping coils, provided for an embodiment of the present invention.

[0018] Figure 6 A support liner and damping coil structure for a toroidal winding superconducting motor with inter-pole damping coils provided in an embodiment of the present invention;

[0019] Figure 7 The magnetic flux passing through the three-phase armature winding of a toroidal winding superconducting motor with inter-pole damping coil provided in this embodiment of the invention when the motor is running as a generator under no-load conditions.

[0020] Figure 8 A magnetic field distribution cloud map of a toroidal winding superconducting motor with inter-pole damping coil provided for an embodiment of the present invention;

[0021] The reference numerals in the attached figures represent: stator core (1), rotor core (2), armature winding (3), superconducting magnet (4), support liner (5), damping coil (6), stator yoke (7), stator tooth (8), rotor yoke (9), rotor tooth (10), superconducting coil (11), Dewar (12), and copper shielding layer (13). Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0023] This invention provides a toroidal winding superconducting motor with inter-electrode damping coils, and the structure of such a toroidal winding superconducting motor with inter-electrode damping coils is as follows. Figure 1 , Figure 2 As shown.

[0024] The motor includes: a stator core (1), a rotor core (2), an armature winding (3), a superconducting magnet (4), a support liner (5), and a damping coil (6); wherein, both the stator core (1) and the rotor core (2) adopt a salient pole structure. The stator core (1) consists of a stator yoke (7) and 12 radially evenly distributed stator teeth (8). The stator teeth adopt a parallel tooth structure, which is beneficial to the installation of the superconducting magnet and the homogenization of the air gap magnetic field. The rotor core (2) consists of a rotor yoke (9) and 8 equally spaced rotor teeth (10). The rotor teeth (10) are arranged in the axial direction, and the geometric parameters of each tooth are exactly the same to ensure the symmetry of the air gap magnetic field and the suppression of torque pulsation.

[0025] To achieve precise installation and efficient heat dissipation of the superconducting magnet (4), improvements were made to the stator structure in this embodiment. The stator core (1) adopts a modular assembly design, that is, the entire stator yoke is cut into four symmetrical sector blocks along the vertical and horizontal directions (e.g., Figure 3 As shown). During the assembly process, the superconducting magnet is first pre-positioned in the stator slot, and then the four stator blocks are assembled to ensure that the superconducting magnet is stably clamped and positioned during the closing process. This design not only facilitates the installation and replacement of the superconducting magnet, but also reserves space for the arrangement of the cryogenic cooling system and the liquid hydrogen / liquid helium evacuation channel, improving the overall assembly processability and operational reliability. The internal structure of the superconducting magnet (4) is as follows. Figure 5 As shown. It includes: a superconducting coil (11), a Dewar (12), and a copper shielding layer (13); each superconducting coil (11) is made of multiple turns of superconducting tape and has a double-layer racetrack-shaped structure. The Dewar (12) is a double-layer vacuum container structure, and the space between its inner and outer layers is evacuated to reduce heat loss; each superconducting coil (11) is placed in the inner layer of the Dewar (12), and liquid nitrogen is introduced into the inner layer to cool the superconducting coil (11).

[0026] like Figure 4 and Figure 6 As shown, mounting slots are machined between adjacent large teeth of the stator core to fix the support liner (5). The support liner is made of a high-strength, insulated, and non-magnetic material. After extensive experiments and trial production, epoxy glass fiber composite material (G10) and alumina ceramic plate are preferred. Its function is to withstand the electromagnetic force during the operation of the superconducting winding and to provide stable support for the damping coil. Several through holes are uniformly opened inside the support liner (5) along the axial direction of the motor, and conductive metal strips (such as copper or aluminum strips) are embedded in them. These conductive strips are shorted at both ends to form multiple closed loops that are electrically isolated from each other, thereby constituting the inter-pole damping coil (6) as described in this invention. The function of the damping coil (6) is that when the motor is subjected to a sudden load disturbance or the rotor generates subsynchronous oscillation, the induced current will be generated in the closed loop, thereby forming a damping magnetic field opposite to the direction of the disturbance magnetic field, effectively suppressing the dynamic distortion and electromagnetic oscillation of the air gap magnetic field, and improving the stability of the system operation and the damping characteristics of the transient process.

[0027] like Figure 7 As shown, when the motor is running under no-load, the flux linkage waveform in the three-phase armature winding is close to a sinusoidal distribution, indicating that the proposed annular winding structure can significantly improve the harmonic content of the air gap magnetic field and reduce the armature potential distortion rate. Figure 8 The magnetic field distribution cloud map of the motor is given. It can be seen that under the excitation of the superconducting magnet, the air gap magnetic flux density is relatively uniform, the peak magnetic flux density is about 2.5T, and the magnetic field of the stator teeth does not show obvious saturation phenomenon, which proves the rationality of the proposed structural design.

[0028] In this embodiment, the superconducting magnet (4) is made of multi-turn high-temperature superconducting tape wound into a double-layer racetrack-shaped coil (e.g. Figure 4 As shown), its advantage is that it can achieve a higher ampere-turns in a limited space, while facilitating the arrangement of cooling channels. The combination of the support plate (5) and the damping coil (6) not only realizes the dual functions of mechanical support and electromagnetic damping, but also achieves comprehensive optimization of structural strength, thermal stability and electromagnetic performance by reasonably designing the plate thickness and damping circuit parameters.

[0029] In summary, this scheme, by introducing inter-pole damping coils and a modular superconducting magnet installation method into the stator structure of the toroidal winding superconducting motor, facilitates the assembly of the superconducting magnet and the arrangement of the cooling system. Furthermore, it effectively improves the air gap magnetic field distribution of the motor and enhances the armature potential waveform quality, thereby suppressing low-frequency oscillations and subsynchronous oscillations during motor operation and improving the system's operational stability and safety. The structural design of this scheme balances electromagnetic and mechanical performance, which is beneficial for the engineering application of high-power superconducting motors, thus expanding its application scope.

[0030] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A toroidal winding superconducting electric machine having interpolar damping coils, characterized by, The main part of the ring-shaped winding superconducting motor comprises a stator core (1), a rotor core (2), an armature winding (3), a superconducting magnet (4), a support backing plate (5) and a damping coil (6); Both the stator core (1) and the rotor core (2) are salient pole structures, the stator core (1) comprises stator yokes (7) and stator teeth (8) arranged in sequence, and the rotor core (2) comprises rotor yokes (9) and rotor teeth (10) arranged in sequence; The armature winding (3) is wound on the stator teeth (8). The superconducting magnet (4) is installed at the gaps of the stator core (1), and at least four gaps are uniformly distributed around the center on the stator core (1). One support backing plate (5) is installed on the stator yoke (7) where each gap is located, and the damping coil (6) is wound on the support backing plate (5).

2. The toroidally wound superconducting machine with interpolar damping coils of claim 1, wherein, The stator core (1) comprises 12 stator teeth (8), and the stator teeth (8) adopt a parallel tooth structure. The rotor core (2) comprises 8 rotor teeth (10) which are equally spaced in the axial direction of the rotor core (2) and have the same structure. The armature winding (3) is wound on four stator teeth (8) which are 90 degrees apart in the circumferential direction and are connected in series.

3. The toroidally wound superconducting machine with interpolar damping coils of claim 2, wherein, The gaps between adjacent stator teeth (8) are used as stator slots, and four large stator slots and eight small stator slots are formed. The superconducting magnet (4) is cross-wound on the stator yokes (7) of the large stator slots in the stator core (1) to form a ring-shaped winding structure, wherein the superconducting magnet (4) after winding is divided into a stator outer yoke coil segment and a stator inner yoke coil segment according to the inner and outer spaces of the stator yokes (7).

4. The toroidally wound superconducting machine with interpolar damping coils of claim 1, wherein, The current directions of two adjacent superconducting magnets (4) are opposite, and the magnetic fields generated by the stator teeth (8) which are 90 degrees apart in space have opposite polarities.

5. The toroidally wound superconducting machine with interpolar damping coils of claim 1, wherein, The internal structure of the superconducting magnet (4) comprises a superconducting coil (11), a Dewar (12) and a copper shielding layer (13). Each superconducting coil (11) is wound by multiple turns of superconducting tape and has a double-layer runway structure.

6. The toroidally wound superconducting machine with interpolar damping coils of claim 5, wherein, The Dewar (12) is a double-layer vacuum container structure, and the space between the inner and outer layers is evacuated to reduce heat loss. Each superconducting coil (11) is placed in the inner layer of the Dewar (12), and liquid nitrogen is injected into the inner layer to cool the superconducting coil (11).

7. The annular winding superconducting electric machine with interpolar damping coils of claim 1, wherein, The support backing plate (5) is fixedly installed between the adjacent two stator teeth (8) of the large stator slot.

8. The toroidally wound superconducting machine with interpolar damping coils of claim 7, wherein, The damping coil (6) is fixedly embedded in the support backing plate (5).

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