Description:A SYSTEM AND A METHOD FOR STARTING HIGH-TEMPERATURE SUPERCONDUCTING (HTS) SYNCHRONOUS MACHINES
FIELD OF INVENTION
[0001] The present disclosure relates to a system and a method to start high-temperature superconducting synchronous machines. More particularly, the invention relates to a system and method for starting the high-temperature superconducting synchronous machines by integrating an electromagnetic damper within the rotor assembly.
BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] In general, High Temperature Superconducting (HTS) synchronous machine has air core topology wherein the stator winding is placed in non-magnetic teeth and rotor HTS pole coils are placed in a rotating cryostat. These rotor HTS pole coils are cooled to required cryogenic temperature using a cryocooler. In this type of configuration, when stator is supplied by multi-phase input, a rotating magnetic field is generated in the stator bore. This rotating magnetic field does not have starting capability and it cannot roll the rotor from stationery condition. Hence, for making the machine self-starting, a separate mechanism is required.
[0004] However, under steady state condition, when rotor HTS pole coils are energized, the rotor magnetic field generated by HTS pole coils gets physically locked with stator magnetic field and an electromagnetic torque is produced because of interaction of these stator and rotor magnetic fields. On the other hand, the rotor HTS pole coils placed in rotating cryostat are maintained at required cryogenic temperature using a cryocooler. To reduce convective heat-in-leak from external atmosphere to cryostat, a high degree vacuum needs to be maintained.
[0005] A state of art JP4790000B2 relates to a vacuum container for superconducting devices and the devices themselves. It addresses heat generation issues caused by eddy currents induced during magnetic flux changes in conventional vacuum vessels by utilizing non-metallic materials like high-resistance resins or ceramics, enhancing thermal insulation and device efficiency.
[0006] Yet another state of art US20160276906A1 relates to a superconducting electrical machine comprising a rotor and a stator. Rotor windings and stator windings, when cooled in respective cryostats, achieve superconductivity. The rotor and stator cryostats circulate coolants to draw heat from windings, maintaining temperatures below superconducting thresholds.
[0007] Another state of art US20100148593A1 relates to a superconducting apparatus and vacuum container for the same .The state of art discusses on a vacuum container for housing therein a superconducting apparatus including first and second partition walls made of magnetic permeable nonmetallic materials, respectively, and facing each other to form a vacuum heat insulation chamber that is adapted to cover a superconductor that generates a magnetic flux.
[0008] Another state of art US6996994B2 relates to a vacuum retention method and superconducting machine with vacuum retention. The prior art discusses on a superconducting machine including a superconductive device and a vacuum enclosure containing and thermally insulating the superconductive device.
[0009] Yet another prior art DK201270604A relates to a wind turbine with sealed off stator chamber .The state of art discusses on a wind turbine comprising a wind turbine tower provided with a nacelle on top, a wind turbine rotor hub with at least one wind turbine blade rotatably mounted at the nacelle, a shaft coupled to the wind turbine rotor hub and a generator.
[0010] The contemporary prior art faces several challenges that necessitate the development of the present invention. The challenges of contemporary High Temperature Superconducting (HTS) synchronous machines include the inability of the rotating magnetic field in the stator to initiate rotor movement, requiring a separate mechanism for self-starting. Additionally, maintaining the rotor HTS pole coils at cryogenic temperatures necessitates a high vacuum to reduce convective heat-in-leak, prompting the need for an electromagnetic damper to provide self-start capability and create a vacuum envelope for the rotating cryostat. These challenges collectively hinder the efficiency and reliability. Thus, there is a pressing need to achieve the same.
OBJECTS OF THE INVENTION
[0011] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
[0012] It is an object of the present subject matter to provide title, which overcomes the aforementioned and other drawbacks existing in the prior art fixture and methods.
[0013] It is a principal object of the present subject matter to introduce a system and a method for starting of the high-temperature superconducting synchronous machines.
[0014] It is another significant object of the present subject matter to propose the system and the method a system and a method to enoble self-start capability for the rotor to improve stability and transient response during load changes.
[0015] It is another significant object of the present subject matter to propose the system and the method with the damper with optimal torsional strength to transfer electromagnetic torque safely to shafts and load and attain micron-sized surface finish for reduced windage losses and improved rotor dynamic behaviour.
[0016] It is another significant object of the present subject matter to propose the system and the method to ensure minimal allowable ovality and eccentricity in damper assembly and buckle-free dampers for shafts under 1 bar atmospheric pressure outside and vacuum inside.
[0017] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taking into consideration with accompanied drawings in which preferred embodiments of the present subject matter are illustrated.
SUMMARY OF THE INVENTION
[0018] This summary is provided to introduce the concept of a a system and a method for starting the high-temperature superconducting synchronous machines. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0019] The invention relates to a system and a method for starting high-temperature superconducting (HTS) synchronous machines. The system comprises of an electromagnetic damper positioned within the rotor assembly of the HTS synchronous machine configured to generate damping forces to counteract mechanical oscillations and vibrations within the rotor system. The electromagnetic damper comprises of a plurality of damper bars positioned in a circular fashion within the rotor assembly, short-circuited rings interconnected with each damper bar to form an electrically short-circuited multi-phase winding and a damper base fabricated from non-magnetic stainless steel integrated within a vacuum sleeve of the HTS synchronous machine to maintain vacuum levels and minimize convective heat-in-leak. A plurality of drive end (DE) and non-drive end (NDE) shafts are positioned at the ends of the rotor assembly configured to affix the electromagnetic damper is affixed and a plurality of cryogenically cooled HTS coils are positioned within the rotating cryostat of the HTS synchronous machine, integrated with the electromagnetic damper to start and stabilise the HTS synchronous machine.
[0020] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter.
[0021] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0022] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of improved fixture or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which
[0023] Fig. 1 illustrates an Electromagnetic damper in HTS Synchronous Machine in accordance with an embodiment of the present disclosure;
[0024] Fig. 2 illustrates a single damper bar of electromagnetic damper Electromagnetic damper assembly in HTS Synchronous Machine in accordance with an embodiment of the present disclosure;
[0025] Fig. 3 illustrates a damper short circuiting ring of Electromagnetic damper assembly in HTS Synchronous Machine in accordance with an embodiment of the present disclosure;
[0026] Fig. 4 illustrates a damper cage of the Electromagnetic damper assembly in HTS Synchronous Machine in accordance with an embodiment of the present disclosure;
[0027] Fig. 5illustrates a damper shell of the Electromagnetic damper assembly in HTS Synchronous Machine in accordance with an embodiment of the present disclosure;
[0028] Fig. 6 illustrates a schematic diagram of an assembly of HTS synchronous machine with the electromagnetic damper onto the rotating cryostat of the rotor in accordance with an embodiment of the present disclosure; and
[0029] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
[0030] A few aspects of the present disclosure are explained in detail below with reference to the various figures. Example implementations are described to illustrate the disclosed subject matter, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations of the various features provided in the description that follows.
[0031] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0032] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the “invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0033] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[0034] Various embodiments are further described herein with reference to the accompanying figures. It should be noted that the description and figures relate to exemplary embodiments and should not be construed as a limitation to the subject matter of the present disclosure. It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the subject matter of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the subject matter of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof. Yet further, for the sake of brevity, operation or working principles pertaining to the technical material that is known in the technical field of the present disclosure have not been described in detail so as not to unnecessarily obscure the present disclosure.
[0035] Fig. 1 illustrates an Electromagnetic damper in HTS Synchronous Machine in accordance with an embodiment of the present disclosure. A system(100) for starting high-temperature superconducting (HTS) synchronous machines comprises of an electromagnetic damper(501) positioned within the rotor assembly(602) of the HTS synchronous machine configured to generate damping forces to counteract mechanical oscillations and vibrations within the rotor system ,a plurality of drive end (DE) (611) and non-drive end (NDE) shafts(612) positioned at the ends of the rotor assembly(602) configured to affix the electromagnetic damper(501) is affixed, a plurality of cryogenically cooled HTS coils(603) positioned within the rotating cryostat of the HTS synchronous machine, integrated with the electromagnetic damper(501) to start the HTS synchronous machine.
[0036] The electromagnetic damper(501)is positioned within the rotor assembly(602), it generates damping forces to counteract mechanical oscillations and vibrations. This enhances the stability of the HTS synchronous machine during operation.
[0037] A plurality of damper bars(101)are positioned in a circular fashion within the rotor assembly(602) and are part of the electromagnetic damper(501). They play a crucial role in generating damping forces.
[0038] A plurality of short circuited rings(201) are interconnected with each damper bar(101), they form an electrically short-circuited multi-phase winding. This configuration enhances the electromagnetic properties of the damper(501).
[0039] A damper base is fabricated from non-magnetic stainless steel, it is integrated within a vacuum sleeve of the HTS synchronous machine. Its role is to maintain vacuum levels and minimize convective heat-in-leak, thus optimizing the performance of the system(100).
[0040] The plurality of Drive End (DE)(611) and Non-Drive End (NDE) Shafts(612)are positioned at the ends of the rotor assembly(602), they serve to affix the electromagnetic damper(501). This ensures proper installation and functioning of the damper(501) within the machine.
[0041] The cryogenically cooled HTS coils(603) are positioned within the rotating cryostat of the HTS synchronous machine, they are integrated with the electromagnetic damper(501)to further stabilize the system. This ensures smooth operation of the machine even at high temperatures.
[0042] The electromagnetic damper(501)is realized by assembling damper cage and damper shell (401) together. The damper cage(301) has damper bars (101) short circuited at each end with the help of damper short circuiting rings (201). The inner surface (405) of this electromagnetic damper(501)encounters the high level vacuum, whereas, the outer surface (406) of electromagnetic damper(501)faces the physical airgap in the machine.
[0043] Fig. 2 illustrates a single damper bar of electromagnetic damper Electromagnetic damper assembly in HTS Synchronous Machine in accordance with an embodiment of the present disclosure. A required number of such damper bars(101)are arranged in circular fashion to realize the damper cage. Each damper bar(101) has a linear portion (102) and, at each end, it has step for short circuit ring connection (104). The damper bar(101) has a curvature (105) so as to assemble it with the damper shell. There are more than one countersunk holes (103) provided for damper bar(101) assembly.
[0044] Fig. 3 illustrates a damper short circuiting ring of Electromagnetic damper assembly in HTS Synchronous Machine in accordance with an embodiment of the present disclosure. The damper short circuiting ring (201) electrically short/connect each damper bar(101) on its ends. For this purpose, required number of steps (205) are provided on the damper short circuiting ring. The inner surface (203) of the damper short circuiting ring is placed onto the damper shell, whereas, the outer surface (202) of the damper short circuiting ring faces the physical airgap in the machine. There are more than one countersunk holes (204) provided in damper short circuiting ring for its assembly on damper shell(401).
[0045] Fig. 4 illustrates a damper cage of the Electromagnetic damper assembly in HTS Synchronous Machine in accordance with an embodiment of the present disclosure. In the damper cage(301) assembly(301) , all the damper bars (101) are connected at joints (302) by brazing method with both DE and NDE side damper short circuiting rings (201). The complete assembly is machined and outer surface of the damper cage(301) is surface finished to micron size so as to have lesser windage losses at rated rotational speeds of the rotor. There are more than one countersunk holes (103, 204) provided in damper bars(101)as well as damper short circuiting ring(201) for its assembly on damper shell(401).
[0046] Fig. 5 illustrates a damper shell of the Electromagnetic damper assembly in HTS Synchronous Machine in accordance with an embodiment of the present disclosure. The cylindrical damper shell acts a vacuum sleeve to rotating cryostat of HTS synchronous machine. The inner surface (405) of this damper shell encounters the high level vacuum. Also, when this damper shell is integrated with damper cage(301) assembly at the step (402) on its outer surface (406), it helps in self-starting of HTS synchronous motor for synchronization and able to able to improve the stability and transient response of machine during sudden load changes. There are more than one tapped holes (403, 404) provided in damper shell for mounting and assembling damper bars(101)as well as damper short circuiting rings.
[0047] Fig. 6 illustrates a schematic diagram of an assembly of HTS synchronous machine with the electromagnetic damper(501)onto the rotating cryostat of the rotor in accordance with an embodiment of the present disclosure. The HTS synchronous machine has a stator assembly (601) and a rotor assembly (602). These stator and rotor assemblies are assembled with each other with a physical airgap (624) between them and the electromagnetic damper (501) is provided on top of the rotor assembly. The stator assembly is realized by placing stator windings (604) in non-magnetic teeth (606). The non-magnetic teeth and stator winding are placed inside a hollow cylindrical back iron shell (607) made of ferromagnetic material to provide a low reluctance path to working magnetic flux of the machine. With the help of support plates (608), this assembly is placed inside the stator frame (605). On each side, the stator frame has Drive End (DE)(611) and Non-Drive END (NDE) covers (609, 610) to provide ingress protection to the machine as well as provide support for the rotor assembly. The rotor assembly(602) has pairs of High Temperature Superconducting (HTS) pole coils (603) placed in a rotating cryostat. The HTS pole coils are cooled to the required cryogenic temperature using a stationary cryocooler (620) placed at the non-drive end of the machine. A rotary coupling (618) is used to transfer cold cryogen from the stationary cryocooler to the rotating cryostat and collect back the warm cryogen from the rotating cryostat to the stationary cryocooler. The connection of the cryocooler to the rotary coupling is provided in an auxiliary chamber (619). To reduce convective heat-in-leak from the atmosphere to the rotating cryostat, a high degree vacuum is maintained in vacuum spaces (625). There is an excitation system (617) in between the NDE shaft and rotary coupling which provides DC current to HTS pole coils. The rotating cryostat is fastened to DE and NDE shafts (611, 612) to enable its spin on its axial axis. For this purpose, two bearings, viz. DE bearing (613) and NDE bearing (614), are provided at respective shaft ends. These DE and NDE bearings are then placed in DE and NDE stator covers using DE and NDE bearing stoppers (615, 616). At the Drive end side of the rotor, a coupling flange (621) is provided to connect the rotor of the machine to the external load. The complete assembly is rested on a base plate (623) through frame mounting legs (622).

WORKING OF INVENTION:

[0048] The proposed system and method have the application in various industries where precise and stable rotational machinery is required. This includes sectors such as power generation, renewable energy, aerospace, transportation (such as high-speed trains), and industrial manufacturing processes requiring high precision and reliability.

ADVANTAGES OF THE INVENTION

[0049] The proposed system and method have the following advantages over the contemporary prior arts:
• Enhanced Stability: The integration of the electromagnetic damper with cryogenically cooled HTS coils within the rotating cryostat improves the stability of high-temperature superconducting (HTS) synchronous machines. By generating damping forces, the damper effectively mitigates mechanical oscillations within the rotor system, leading to smoother operation and reduced wear and tear.
• Increased Efficiency: The activation of the electromagnetic damper helps to optimize the performance of HTS synchronous machines by stabilizing the rotor assembly. This stabilization reduces energy losses associated with vibrations and mechanical oscillations, thereby increasing overall efficiency.
• Improved Reliability: By affixing the electromagnetic damper to both the drive end and non-drive end shafts of the rotor assembly, the invention enhances the reliability of HTS synchronous machines. The damper provides additional support and damping capabilities, reducing the risk of mechanical failures and downtime.
• Vacuum Sleeve Integration: Mounting the electromagnetic damper within a vacuum sleeve of the rotating cryostat helps maintain optimal vacuum levels and minimizes convective heat-in-leak. This ensures the proper functioning of the HTS synchronous machine, even under challenging operating conditions.
• Versatility: The invention can be adapted for use in various HTS synchronous machine configurations and applications. Its ability to stabilize the rotor assembly and mitigate mechanical oscillations makes it suitable for a wide range of industrial and commercial settings.
• Cost-Effectiveness: Despite its advanced capabilities, the electromagnetic damper is designed for cost-effective implementation. Its integration with existing HTS synchronous machine components minimizes the need for extensive modifications or additional equipment, making it a practical solution for enhancing machine performance.

[0050] The above description does not provide specific details of the manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0051] Further, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other fixture or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0052] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0053] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different fixture or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
, Claims:We Claim:
1. A system for starting of high-temperature superconducting (HTS) synchronous machines(100), the system(100) comprising:
an electromagnetic damper(501) positioned within the rotor assembly(602) of the HTS synchronous machine configured to generate damping forces to counteract mechanical oscillations and vibrations within the rotor system, wherein the electromagnetic damper(501) comprises of
a plurality of damper bars(101)positioned in a circular fashion within the rotor assembly(602);
a plurality of short circuited rings(201) interconnected with each damper bar(101) to form an electrically short-circuited multi-phase winding; and
a damper shell fabricated from non-magnetic stainless steel integrated within a vacuum sleeve of the HTS synchronous machine to maintain vacuum levels and minimize convective heat-in-leak;
a plurality of Drive End (DE)(611) and Non-Drive End (NDE) Shafts(612)positioned at the ends of the rotor assembly(602) configured to affix the electromagnetic damper(501); and
a plurality of cryogenically cooled HTS coils(603) positioned within the rotating cryostat of the HTS synchronous machine, integrated with the electromagnetic damper(501)to stabilize the HTS synchronous machine.
2. The system(100) for starting of high-temperature superconducting (HTS) synchronous machines as claimed in the claim 1, wherein the plurality of damper bars(101) comprise of a linear portion(102) constructed from high-conductivity materials, a damper bat curvature(105) configured for assembly with a damper shell(401) and one / more countersunk holes(103) for attachment within a damper cage(301).
3. The system(100) for starting of high-temperature superconducting (HTS) synchronous machines as claimed in the claim 1 or 2, wherein the damper bars(101)are composed of materials including aluminum, aluminum alloy, copper, copper alloy, copper-silver alloy, copper-nickel alloy, or copper-zirconium alloy.
4. The system(100) for starting of high-temperature superconducting (HTS) synchronous machines as claimed in the claims 1-3, wherein the short-circuiting ring(201) comprises of a ring structure constructed from high-conductivity materials, a plurality of steps / protrusions(205) for connection with damper bars(101)and one / more countersunk holes(204) for attachment to a damper shell.
5. The system(100) for starting of high-temperature superconducting (HTS) synchronous machines as claimed in the claims 1-4, wherein the damper shell(401) comprises of a cylindrical structure serving as a vacuum sleeve (Damper shell acts as vacuum sleeve) for the rotating cryostat of a high-temperature superconducting synchronous machine, a plurality of steps or mounting features(402) and a plurality of tapped holes(403) / fastening mechanisms(404) for attachment of damper bars(101)and short-circuiting rings(201).
6. The system(100) for starting of high-temperature superconducting (HTS) synchronous machines as claimed in the claims 1-5, wherein the damper bars(101)are interconnected with the short circuited rings(201) to form a damper cage(301).
7. The system(100) for starting of high temperature superconducting (HTS) synchronous machines as claimed in the claims 1-6,wherein the damper cage(301) comprises of a plurality of damper bars(101)arranged in a circular fashion and electrically interconnected with short-circuiting rings(201) and joints(302) / connections between damper bars(101)and short-circuiting rings(201).
8. The system(100) for starting of high-temperature superconducting (HTS) synchronous machines as claimed in the claims 1-7, wherein the damper cage(301) is affixed to the damper base forming an integrated electromagnetic damper(501)with a vacuum shell.
9. The system(100) for starting of high-temperature superconducting (HTS) synchronous machines as claimed in the claims 1-8, wherein the drive end(611) and non-drive end shafts(612) of a rotor ensure symmetrical distribution of damping forces across the rotor assembly(602) and facilitate stabilization of the HTS synchronous machine.