Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
  • H02K3/18—Windings for salient poles
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F6/00—Superconducting magnets; Superconducting coils
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F27/00—Details of transformers or inductances, in general
  • H01F27/28—Coils; Windings; Conductive connections
  • H01F27/2871—Pancake coils
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
  • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
  • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
  • H01F41/048—Superconductive coils
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
  • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
  • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
  • H01F41/06—Coil winding
  • H01F41/061—Winding flat conductive wires or sheets
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F6/00—Superconducting magnets; Superconducting coils
  • H01F6/06—Coils, e.g. winding, insulating, terminating or casing arrangements therefor
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K55/00—Dynamo-electric machines having windings operating at cryogenic temperatures
  • H02K55/02—Dynamo-electric machines having windings operating at cryogenic temperatures of the synchronous type
  • H02K55/04—Dynamo-electric machines having windings operating at cryogenic temperatures of the synchronous type with rotating field windings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
  • Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment

Definitions

• the invention relates to superconducting magnetic coils .
• Superconductors may be used to fabricate superconducting magnetic coils such as solenoids, multipole magnets, etc., in which the superconductor is wound into the shape of a coil-.
• the temperature of the coil is sufficiently low that the superconductor can exist in a superconducting state, the current carrying capacity as well as the magnitude of the magnetic field generated by the coil is significantly increased.
• Typical superconducting materials include niobium- titanium, niobium-tin, and also copper oxide ceramics such as members of the rare-earth-copper-oxide family (i.e., YBCO) , the thallium-barium-calcium-copper-oxide family (i.e., TBCCO) , the mercury-barium-calcium-copper-oxide family (i.e., HgBCCO) , and the bismuth-strontium-calcium- copper-oxide family (with or without lead substitutes, i.e.
• YBCO rare-earth-copper-oxide family
• TBCCO thallium-barium-calcium-copper-oxide family
• HgBCCO mercury-barium-calcium-copper-oxide family
• bismuth-strontium-calcium- copper-oxide family with or without lead substitutes, i.e.
• the superconductor may be formed in the shape of a thin tape which allows the conductor to be bent around the diameter of a core.
• high temperature superconductor is often fabricated as a thin tape m which multi -filament composite superconductor including individual superconducting filaments extends substantially tne iengtn of the multi-filament composite conductor and are surrounded by a matrix- forming material, which is typically- silver or another noble metal.
• a matrix- forming material typically- silver or another noble metal.
• the matrix forming material conducts electricity, it is not superconducting.
• the superconducting filaments and the matrix- forming material form the multi-f1lament composite conductor.
• the superconducting filaments and the matrix- forming material are encased m an insulating layer (not shown) .
• pancake winding m wnich the superconductor tape is wound one turn on top of a preceding turn thereby forming a plane of turns perpendicular to the axis of the coil.
• the pancake coils can be wound as double pancakes.
• a superconducting magnetic coil assembly using pancake coils may include several coils, coaxially disposed along the length of the coil assembly. The individual coils are interconnected using short lengths of superconducting wire or ribbon made from the superconducting materials of the type described above, for example, copper oxide ceramic.
• variable-profile and saddle-shaped coils are advantageously used m applications where the superconducting magnetic coil is required to conform to or be positioned within an annular region of an assembly, such as a rotating electric machine.
• the invention features a superconducting coil having a conical or tapered profile.
• the superconducting coil includes a superconductor tape wound concentrically about and disposed along an axis of the coil to provide a plurality of concentric turns defining an opening having a dimension which gradually decreases, in the direction along the axis, from a first end to a second end of the coil.
• Each turn of the superconductor tape has a broad surface maintained substantially parallel to the axis of the coil .
• the decreasing dimension opening defined by the winding configuration of the coil provides a coil having a tapered profile.
• the tapered superconducting coil is well-suited for use m applications where the coil is to be positioned in annularly- shaped volumes, such as those commonly found m rotating electric machines (e.g., motors or generators.)
• the tapered arrangement eliminates stepped profiles, common with other stacked arrangements.
• the tapered superconducting coil requires relatively fewer stacked individual coils to fill annularly- shaped volumes. This is m contrast to other superconducting coil assemblies, which require stacking of many more thin, individual coils to fill an annularly- shaped volume.
• reducing tr.e number of individual coils, m reduces the number of electrical connections between the individual coils, thereby increasing the overall performance and reliability of a coil assembly using tapere coils .
• the superconductor tape of the present invention is wound with its broad surface maintained substantially parallel to the axis of the coil (as well as to ad]acent turns.) This feature is particularly advantageous when the tape is formed of less flexible, brittle materials, such as ceramic-based high temperature superconducting materials.
• tapered configuration provides better critical current (I c ) retention characteristics and allows for better coil grading.
• a superconducting coil assembly in another aspect of the invention, includes a plurality of superconducting coils m a stacked arrangement, each having the characteristics described above. Because the turns of superconductor tape for each coil has its broad surface maintained substantially parallel to the axis of the coil assembly, the individual coils are easily stacked without the need for spacers or wedges.
• the coils are substantially identical, which is particularly advantageous m certain applications (e.g., rotating machines) where the coil assembly is to be placed within a predefined annularly- shaped volume.
• a top and a bottom coil e.g., pancakes
• a top and a bottom coil at each end of the stack (a first end coil and a second end coil, respectively) are preselected to have a higher critical current retention characteristic tnan critical current retention characteristic of the coils positioned between the top and bottom coils of the stack
• groups of coils at the top and bottom ends of the coil assembly may be preselected to have a higher critical current retention characteristic.
• Positioning top and bottom pancake coils witn higner critical current retention characteristics in this manner can significantly lower the power loss of the total coil assembly.
• the top and bottom pancake coils can be preselected by their intrinsic properties or, alternatively, with small changes in the superconductor tape dimensions.
• Embodiments of these aspects of the invention may also include one or more of the following features.
• the superconductor tape is wound m a racetrack shape defining a pair of opposing arcuate end sections and a pair of opposing substantially straight side sections
• the superconductor tape includes a multi- filament composite superconductor including individual superconducting filaments which extend the length of the multi-f ⁇ lament composite conductor and are surrounded by a matrix- forming material.
• the superconductor tape preferably includes an anisotropic high temperature superconductor, such as (Bi, Pb) 2 Sr 2 Ca 2 Cu 3 0
• the superconductor tape includes a copper oxide ceramic, sucn as those which are members of the rare-earth-copper-oxide family (i.e., YBCO . )
• the superconductor tape includes a pair of superconductor layers and at least one mechanical reinforcing layer.
• the pair of superconductor layers are disposed between a pair of mechanical reinforcing layers, each reinforcing layer including stainless steel.
• the superconducting coil is m the form of a pancake coil, such as a double pancake coil.
• the superconductor tape s wound to provide a linearly tapered inner surface of tne coil extending along the axis of the coil.
• the superconductor tape is wound to provide a curved inner surface of the coil extending along the ax s of the coil.
• the curved inner surface of the wound superconductor tape is cylind ⁇ cally-shaped along the opposing substantially straight side sections and spherically-shaped along the opposing arcuate end sections.
• a method of providing a superconducting coil includes the following steps.
• a superconductor tape is wound about an axis of the coil to provide concentric turns defining an opening navmg an inner dimension w th a broad surface of the superconductor tape maintained substantially parallel to the axis of the coil.
• the tape is wound so tnat the opening gradually decreases from a first end to a second end m the direction along the axis.
• Embodiments of this aspect of the invention includes one or more of the following features.
• the superconducting coil is wound using a mandrel having surfaces which define the taper.
• the surfaces may be linearly tapered or curved (e.g., cylmdrically-shaped or spherically-shaped.)
• a pair of heated plates are used to apply heat and pressure to mold the superconducting coil into a tapered profile.
• Fig. 1 is a perspective, partially cutaway view of a superconducting coil m accordance with the invention.
• Fig. 2 is a cross-sect cna side view of a portion of a superconductor tape for winding the superconducting
• Fig. 3 is an exploded view of a portion of the superconducting coil along line 3-3 of Fig. 1.
• Fig. 4 is a perspective view of a mandrel suitable for winding tne superconducting coil of Fig. 1.
• Fig. 5A and 53 illustrate an alternative approacn for forming the superconducting coil of Fig. 1.
• Fig. ⁇ is a perspective view of an alternative embodiment of a superconducting coil.
• Fig. 7 is an exploded view of a portion of the superconducting coil along line 7-7 of Fig. 6.
• Fig. 8 is a perspective view of a mandrel suitable for winding the superconducting coil of Fig. 6.
• Fig. 9 is a cross-sectional end view of a portion of a rotor including the superconducting coil of Fig. 6.
• a tapered superconducting coil 10 includes a superconductor tape 12 wound generally m an elongated oval or racetrack shape.
• the "racetrack-shaped" superconducting coil 10 includes a pair of opposing and generally straight side sections 14a and a pair of opposing curved end sections 14b, which together form a generally rectangularly- shaped coil with rounded corners. It is important to note that although coil 10 is “racetrack- shaped, " it does not have the shape or structure of the well-known racetrack coil.
• coil 10 is wound about an axis 16 of the coil from a continuous length or series of lengths of superconductor tape, thereby forming a number of windings or turns 18 of the coil (see Fig. 3.)
• the turns in combination, define an opening 19 wnich, as will be described m greater detail below, increases m size from the innermost turn to the outermost turn.
• This approach for winding the superconductor tape is often referred to as pancake winding, in which the superconductor tape is wound one turn on top of a preceding turn thereby forming a plane of turns perpendicular to axis 16 of coil 10.
• superconductor tape 12 includes broad sides 22 and narrow sides 24.
• superconductor tape includes a multi- filament composite superconductor layer 25 having individual superconducting filaments extending substantially the length of the multi- filament composite conductor and surrounded by a matrix- forming material, such as silver.
• the superconducting filaments and matrix- forming material together form the multi-fllament composite conductor.
• the superconduc ing filaments and the matrix-forming material are encased m an insulating layer (not shown) .
• a pair of superconductor layers 25 are sandwiched between a pair of reinforcement members 26, for example of stainless steel, which provide mechanical support to the superconductor layers 20.
• reinforcement members 26 for example of stainless steel
• each turn 18 of superconductor tape 12 is wound such that each turn is sligntly offset, m the direction of axis 16, from a preceding turn so that from the innermost turn 18a (Fig. 1) to the outermost turn 18b, coil 10 is wound m tapered fashion along an imaginary line 28. It is important to note that broad sides 22 of each turn 18 are parallel to each other and to axis 16.
• a mandrel 30 is formed here, for example, of aluminum and is used with a winding mechanism carrying spools of the superconductor layers and stainless reinforcing members (neither shown) to wind superconductor coil 10.
• Mandrel 30 includes a central mounr section 32 surrounded by opposing tapering side sections 34 and opposing tapering end sections 36.
• Mandrel defines tne shape and degree of taper for winding coil 10.
• a tool (not shown) follows the surface of mandrel 30 and guides superconductor tape 12 m place on the mandrel .
• superconducting coil 10 is formed first as a conventional pancake coil 10a, without tapered edges; that is, each turn of coil 10a lies directly and entirely over the preceding turn.
• Kapton ® film (a product of E.I. duPont de Nemours and Company, Wilmington, DE) having a B- staged epoxy is wrapped "m-hand" with superconductor tape 12 during the winding process of the pancake coil .
• the epoxy has a tacky characteristic which helps hold the adjacent turns together.
• pancake coil 10a is then placed between a pair of heating plates 40 having tapered surfaces 42, which define the shape and desired degree of taper for superconducting coil 10.
• heating plates 40 are brought together (m tne direction of arrow 43, as shown m Fig. 5A) and heat and pressure are applied to pancake coil 10a, thereby forming superconducting coil 10.
• the heat and pressure are removed after a predetermined period of time, to allow the epoxy to cool so that the adjacent turns of superconducting coil 10 are bonded together.
• Fig. 6 an alternative embodiment of a superconducting coil 100 is shown wound with the same superconductor tape 12 described above for winding co l 10.
• superconductor tape 12 is wound so that regions of the tape along opposing side sections 104a are cylmdrically tapered while regions of tne tape along opposing end sections 104b are spne ⁇ cally tapered.
• superconductor tape 12 is wound at both side sections 104a and end sections 104b m tapered fashion along an imaginary curved line 106. Because side sections 104a are straight in the plane of the coil, tapering along these sections is based en a cylinder. At rounded end sections 104b, on the other hand, the tapering is based on a quartered section of a spnere . Note that as was the case with the linearly tapered embodiment described above, the broad sides 22 of each turn of the superconductor tape m this case are still parallel to eacn other and to axis 16.
• Mandrel 130 for forming superconduc ing coil 100 is shown.
• Mandrel 130 is essentially the same as mandrel 30 described above except that the surfaces of opposing tapering side sections 134 and opposing tapering end sections 136 are rounded to define the curved shape of rounded side sections 104a and end sections 104b.
• a rotor assembly 200 for a synchronous motor has a four-pole topology without its outer shield for enclosing the vacuum layer within the overall assembly.
• rotor assembly 200 includes a torque tube 220 fabricated from a high-strength, ductile and non-magnetic material (e.g., stainless steel) .
• tne torque tube 220 supports four superconducting coil assemblies 230 (only two are shown, ) each winding associated with a pole of the motor.
• Coil assemblies 230 are positioned within the inner volume of the torque tube to provide a low reluctance flux path for magnetic fields generated by coil assemblies 230.
• annular regions 240 are not well -suited for receiving superconducting coil configurations, such as stacked pancake and racetrack coils.
• the coil assemblies be constructed with individual coils (e.g., pancakes) whicn are staggered m stair-step fashion.
• individual coils e.g., pancakes
• Connecting the individual coils m these arrangements is non-trivial and the torque tube is generally required to be machined with a corresponding stair-step surface to support the coil assemblies, adding cost and complexity to the manufacture of the motor.
• superconducting coil 10 and superconducting coils 100 are tapered, either linearly or m a curved manner, either coil assembly can conform within and fill annular regions 240. Unlike, the stacked pancake arrangements described above, far fewer coils are needed to fill the space, thereby reducing the number of connections and increasing the reliability and performance of the coil assemblies. Thus, a more efficient, easy to assemble motor construction is provided. Moreover, tapered coils are advantageously positioned closer to the armature of the motor.
• annular regions may be formed such that the stacked tapered superconducting coils are substantially identical, which further reduces manufacturing costs.
• a stacked set of substantially identical tapered superconducting coils are simply connected and positioned within the annular region.
• conical or tapered superconducting coil Another important advantage of the conical or tapered superconducting coil is that, in a stacked arrangement, the configuration has the benefit of shielding inner ones of the stacked coils from fields perpendicular to the broad face of the superconductor tape.
• a series of the tapered superconducting coils can be stacked so that the those coils having better performance characteristics are placed on the top and bottom of the stack.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Superconductors And Manufacturing Methods Therefor (AREA)
• Superconductive Dynamoelectric Machines (AREA)

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• 1999
  • 1999-07-23 US US09/359,497 patent/US6509819B2/en not_active Expired - Lifetime
• 2000
  • 2000-05-23 JP JP2001512596A patent/JP3953813B2/ja not_active Expired - Fee Related
  • 2000-05-23 BR BR0012701-9A patent/BR0012701A/pt not_active IP Right Cessation
  • 2000-05-23 KR KR1020027000951A patent/KR100635170B1/ko not_active Expired - Fee Related
  • 2000-05-23 EP EP00963251.4A patent/EP1212760B2/en not_active Expired - Lifetime
  • 2000-05-23 CN CNB008122725A patent/CN1316517C/zh not_active Expired - Fee Related
  • 2000-05-23 WO PCT/US2000/014105 patent/WO2001008173A1/en not_active Ceased
  • 2000-05-23 AU AU74692/00A patent/AU763545B2/en not_active Ceased
  • 2000-05-23 CA CA002380228A patent/CA2380228A1/en not_active Abandoned
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