(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2007/0188284 A1
`Dobbs
`(43) Pub. Date:
`Aug. 16, 2007
`
`US 2007 O188284A1
`
`(54) SHIELDED POWER COUPLING DEVICE
`(76) Inventor: John M. Dobbs, Beverly, MA (US)
`Correspondence Address:
`MCDERMOTT WILL & EMERY LLP
`28 STATE STREET
`BOSTON, MA 02109-1775 (US)
`(21) Appl. No.:
`11/699,529
`1-1.
`(22) Filed:
`
`Jan. 29, 2007
`O
`O
`Related U.S. Application Data
`(63) Continuation-in-part of application No. 10/787,270
`filed on Feb. 26, 2004
`s1- ws
`• 1 as
`(60) Provisional application No. 60/450,038, filed on Feb.
`26, 2003.
`s
`
`Publication Classification
`
`51) Int. C.
`(51)
`HOIF 2/06
`
`(2006.01)
`
`(52) U.S. Cl. .............................................................. 336/120
`
`(57)
`
`ABSTRACT
`
`Axisymmetric solid of revolution derivable from section at
`FIG. 5 is generally toroidal with electric current(s) in
`windings 110, 160 preferably flowing circumferentially
`along major circle(s) during power coupling device opera
`tion. Current(s) in windings 110, 160; current(s) in half
`shields 120, 170; and the volume of space swept out by
`shield airgap(s) 101 emerge from plane of paper perpen
`dicularly at FIG. 5 but as these emerge therefrom they curve
`to follow toroidal major circle(s). Cores 115, 165 preferably
`shunt and align magnetic flux such that magnetic field lines
`escape therefrom primarily only in region(s) of core air
`gap(s) and such that magnetic flux loops lie in planes of
`toroidal minor circle(s). Half-shield(s) 120, 170 preferably
`have electrically conductive material(s) distributed therein
`as is sufficient to Substantially cancel magnetic flux lines
`impinging thereon before effects of Such impinging mag
`netic flux lines would reach shield airgap(s) 101 and/or outer
`surface(s) of half-shields 120, 170.
`
`Electric Current flows in
`direction of major circle
`
`
`
`y
`
`(-160
`
`110
`
`- Magnetic flux flows in
`direction of minor circle
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 001
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 1 of 23
`
`US 2007/0188284 A1
`
`Electric Current flows in
`direction of major circle
`
`y
`
`-
`
`
`
`110
`
`direction of minor Circle
`
`FIG. 1
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 002
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 2 of 23
`
`US 2007/0188284 A1
`
`
`
`FIG 2
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 003
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 3 of 23
`
`US 2007/0188284 A1
`
`Ampere's Circuital Law
`
`Hd NI
`
`D O S-e
`
`to path of the line
`integral
`
`FIG 3
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 004
`
`

`

`104\
`__
`\
`
`\N[
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`
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`v7~
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`_
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`Y
`
`7
`
`
`
`FIG. 4
`
`Momentum Dynam ics Corporation
`Exhibit 1026
`Page 005
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 005
`
`

`

`enal
`
`oe)%=eSee~S=aN—wo—~
`
`
`
`FIG. 5
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 006
`
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 6 of 23
`
`US 2007/0188284 A1
`
`
`
`120
`
`FIG. 6
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 007
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 7 of 23
`
`US 2007/0188284 A1
`
`
`
`120
`
`to or
`
`-----is--
`s 170
`
`FIG. 7
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 008
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 8 of 23
`
`US 2007/0188284 A1
`
`--
`
`at
`
`r"
`
`---
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`OOO OOO
`IOC
`XOC)
`
`
`
`weverahermarriswanaanaaramwaaaaaaaaaaaaa
`
`Hwa
`
`170
`
`FIG. 8
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 009
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 9 of 23
`
`US 2007/0188284 A1
`
`
`
`170
`
`FIG. 9
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 010
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 10 of 23
`
`US 2007/0188284 A1
`
`
`
`170
`
`FIG 10
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 011
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 11 of 23
`
`US 2007/0188284 A1
`
`
`
`
`
`
`
`110-1 is % N
`
`2N2
`16O
`s
`165
`170-su
`
`
`
`
`
`
`
`u-160
`- 165
`3-79
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`
`
`
`
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`
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`
`
`
`
`
`
`
`
`
`N
`22 NN2 É 2 S N&S
`
`%
`
`2
`N
`
`
`
`120
`115 %
`110
`2
`
`16O
`165
`170
`
`FIG 11
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 012
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 12 of 23
`
`US 2007/0188284 A1
`
`OO
`
`
`
`FIG. 12
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 013
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 13 of 23
`
`US 2007/0188284 A1
`
`
`
`221
`22O
`
`M
`Y-Axis of Rotation
`
`F.G. 13
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 014
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 14 of 23
`
`US 2007/0188284 A1
`
`
`
`F.G. 14
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 015
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 15 of 23
`
`US 2007/0188284 A1
`
`
`
`. of Rotation
`
`FG 15
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 016
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 16 of 23
`
`US 2007/0188284 A1
`
`4OO
`
`
`
`455
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 017
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 17 of 23
`
`US 2007/0188284 A1
`
`
`
`21 O
`
`F.G. 17
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 018
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 18 of 23
`
`US 2007/0188284 A1
`
`
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 019
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 19 of 23
`
`US 2007/0188284 A1
`
`
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 020
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 20 of 23
`
`US 2007/0188284 A1
`
`310
`
`
`
`380
`
`\
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 021
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 21 of 23
`
`US 2007/0188284 A1
`
`-
`
`FIG 21
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 022
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 22 of 23
`
`US 2007/0188284 A1
`
`
`
`330
`
`31 O
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 023
`
`

`

`Patent Application Publication Aug. 16, 2007 Sheet 23 of 23
`
`US 2007/0188284 A1
`
`
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 024
`
`

`

`US 2007/0188284 A1
`
`Aug. 16, 2007
`
`SHIELDED POWER COUPLING DEVICE
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`0001) This application is a continuation-in-part applica
`tion claiming benefit of priority under 35 USC 120 from
`commonly owned U.S. patent application Ser. No.
`10/787270, filed 26 Feb. 2004, entitled “Power Coupling
`Device.” now pending, which in turn claims benefit of
`priority under 35 USC 119(e) from U.S. Provisional Appli
`cation Ser. No. 60/450038, entitled “Non-Contacting Power
`Coupling Device.” filed 26 Feb. 2003, now expired; more
`over, the content of said application Ser. No. 10/787270 and
`the content of said Provisional Application Ser. No.
`60/450038 are hereby incorporated herein by reference in
`their entireties.
`
`FEDERALLY SPONSORED RESEARCH
`0002) Not applicable.
`NAMES OF PARTIES TO JOINT RESEARCH
`AGREEMENT
`0003) Not applicable.
`INCORPORATION BY REFERENCE OF
`MATERIAL ON COMPACT DISC
`0004) Not applicable.
`0005 1. Field
`0006) The present disclosure relates to a shielded power
`coupling device; more particularly, relates to a shielded
`power coupling device capable of reducing radio frequency
`(RF) emission and/or other electromagnetic interference,
`reducing leakage inductance, and/or improving efficiency
`during inductive transfer of electric power in the context, for
`example, of a computed tomography (CT) scanner such as
`might be used in medical or security applications or the like,
`or in the context of other such applications where transfer of
`electric power between or among bodies capable of engag
`ing in relative rotation is desired.
`0007 2. Background
`0008 When power coupling devices are used to induc
`tively transfer electric power in noncontact fashion, e.g.,
`from stationary subsystems to rotating subsystems in medi
`cal CT scanners or the like, it is often desired that such
`power coupling devices be shielded. Lack of adequate
`shielding may, for example, result in undesirable RF emis
`Sion, increased leakage inductance, and/or reduced power
`transfer efficiency. Moreover, where power is being trans
`ferred between or among bodies capable of engaging in
`relative rotation, it may be impossible or impractical to
`employ an unbroken Faraday cage or other such integral
`shield that would completely surround the power coupling
`device, it being instead necessary to employ a shield that
`only partially encloses the power coupling device or to
`divide such shield into multiple parts split so as to form
`gap(s) permitting relative rotation between or among such
`bodies.
`
`SUMMARY
`0009. In accordance with one aspect of the present inven
`tion, a shielded power coupling device is designed to reduce
`
`radio frequency (RF) emission and/or other electromagnetic
`interference, reduce leakage inductance, and/or improve
`efficiency during inductive transfer of electric power in the
`context, for example, of a computed tomography (CT)
`Scanner such as might be used in medical or security
`applications or the like, or in the context of other such
`applications where transfer of electric power between or
`among bodies capable of engaging in relative rotation is
`desired. For example, shielded power coupling device(s) in
`accordance with embodiment(s) of the present invention
`might to be used to transfer power of on the order of 2.5 kW
`or more as might be required to operate a CT scanner
`employed in a security-related application or the like; or,
`shielded power coupling device(s) in accordance with
`embodiment(s) of the present invention might to be used to
`transfer power of on the order of 25 kW or more as might
`be required to operate a CT scanner employed in a medical
`application or the like.
`0010. An axisymmetric solid of revolution derivable
`from cross-sectional profile shown at FIG. 5 is generally
`toroidal with electric current(s) in windings 110, 160 pref
`erably flowing circumferentially, e.g., along toroid major
`circle(s), during power coupling device operation. Cur
`rent(s) in windings 110, 160; current(s) in shield(s) 120, 170:
`and the Volume of space swept out by airgap(s) 101 during
`operation of the shielded power coupling device emerge
`from the plane of the paper perpendicularly at FIG. 5 but as
`these emerge therefrom they curve to follow toroid major
`circle(s). Shield(s) 120, 170 may be, for example, two-part
`wraparound shield(s) comprising half-shields 120, 170 hav
`ing shield airgap(s) adjacent to core airgap(s); it is alterna
`tively or additionally possible to employ any suitable shield
`configuration, including, without limitation, the following
`configurations: single-part, multipartite, adjacent-airgap.
`nonadjacent-airgap, cutback, wraparound, and so forth.
`Cores 115, 165 preferably shunt and align magnetic flux
`Such that magnetic field lines escape therefrom primarily
`only in region(s) of core airgap(s) and such that magnetic
`flux loops linking respective cores 115, 165 lie in meridional
`planes, e.g., planes of toroid minor circles(s). Half-shield(s)
`120, 170 preferably have electrically conductive material(s)
`distributed therein as is sufficient to permit flow of electric
`current(s) such as will induce magnetic field(s) capable of
`Substantially canceling magnetic flux lines impinging
`thereon before effects of such impinging magnetic flux lines
`would reach shield airgap(s) 101 and/or outer surface(s) of
`half-shields(s) 120, 170; e.g., before electric current(s)
`induced in half-shield(s) 120, 170 by such impinging flux
`lines would be conducted to shield airgap(s) 101 and/or
`outer surface(s) of half-shields(s) 120, 170.
`0011. In a representative meridional section of one
`embodiment such as is shown in FIG. 5, field-canceling
`currents flowing in half-shields(s) 120, 170; currents flowing
`in windings 110, 160; and volumes of space swept out by
`shield airgap(s) 101 are all preferably substantially mutually
`parallel; moreover, lines of aligned magnetic flux linking
`cores 115, 165 are substantially perpendicular to field
`canceling currents flowing in half-shields(s) 120, 170; to
`currents flowing in windings 110, 160; and to imaginary
`Surfaces bounding volumes of space swept out by shield
`airgap(s) 101. That is, magnetic field(s) preferably have no
`Substantial component parallel to an imaginary surface
`bounding the Volume of space swept out by shield airgap(s)
`101 during operation of the power coupling device, and the
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 025
`
`

`

`US 2007/0188284 A1
`
`Aug. 16, 2007
`
`net current(s) flowing in half-shields(s) 120, 170 preferably
`have no component perpendicular to an imaginary Surface
`bounding the Volume of space Swept out by shield airgap(s)
`101 during operation of the power coupling device. That is,
`fringing field(s) 103 preferably do not have a component
`which would tend to cause induced electric currents to cross
`shield airgap(s) 101.
`0012 Half-shield(s) 120, 170 preferably have electrically
`conductive material(s) at Such location(s), in Such distribu
`tion(s), and in Such electrical conductivity or conductivities
`and thickness(es) as is sufficient to permit flow of electric
`current(s) such as will induce magnetic field(s) capable of
`Substantially canceling magnetic flux lines impinging
`thereon before effects of Such impinging magnetic flux lines
`would reach shield airgap(s) 101 and/or outer surface(s) of
`half-shields(s) 120, 170; e.g., before electric current(s)
`induced in half-shield(s) 120, 170 by such impinging flux
`lines would be conducted to outer surface(s) of half-shield(s)
`120, 170. More preferably, half-shield(s) 120, 170 comprise
`electrically conductive material(s) forming Substantially
`continuous electrical path(s) constituting closed electric
`circuit(s) around the axis of rotation, e.g., circumferential
`path(s) along circle(s) coaxial with major circle(s) of the
`toroidal volume occupied by the overall axisymmetric struc
`ture. More preferably, such continuous electrical path(s) are
`capable of Supporting electric current(s) sufficient to induce
`magnetic field(s) such as will Substantially cancel magnetic
`field(s) due to electric current(s) flowing in windings 110.
`160 during operation of the power coupling device.
`0013 This being the case, it is therefore preferred in one
`or more embodiments of the present invention that half
`shield(s) 120, 170 have, adjacent to core airgap(s), fringe
`field canceling Zone(s) of thickness(es) and electrical con
`ductivity or conductivities sufficient to substantially cancel
`fringing fields due to magnetic flux emanating from core
`airgap(s) before effects of Such emanating magnetic flux
`would reach shield airgap(s) 101 and/or outer surface(s) of
`half-shields(s) 120, 170; e.g., before electric currents pro
`duced thereby in half-shield(s) 120, 170 would be conducted
`to outer surface(s) of half-shield(s) 120, 170. It is further
`more preferred that, where present, such fringe field can
`celing Zone(s) comprise electrically conductive material
`forming Substantially continuous electrical path(s) consti
`tuting closed electric circuit(s) around the axis of rotation,
`e.g., circumferential path(s) along circle(s) coaxial with
`major circle(s) of the toroidal volume occupied by the
`overall axisymmetric structure. It is still furthermore pre
`ferred that continuous electrical path(s) at fringe field can
`celing Zone(s), where present, be capable of Supporting
`electric current(s) sufficient to induce magnetic field(s)
`capable of Substantially canceling magnetic field(s) due to
`electric current(s) flowing in windings 110, 160 during
`operation of the power coupling device.
`0014. It is furthermore preferred that arrangement of
`windings 110, 160 and/or distribution of reluctance-lower
`ing material at cores 115, 165 be such as to align magnetic
`flux Such that magnetic flux loops lie in meridional planes,
`e.g., planes of minor circle(s) where the overall axisymmet
`ric structure is more or less toroidal. It is furthermore
`preferred in one or more embodiments of the present inven
`tion that E-cores or the like having multiple core recesses be
`employed so as to permit a net instantaneous current in the
`primary windings of Substantially Zero (i.e., Such that
`
`respective magnetization currents at respective primary
`windings mutually cancel). It is furthermore preferred, espe
`cially where core(s) 115, 165 comprise a multiplicity of core
`segments, that there be minimal interruption to axisymme
`try, e.g., due to arrangement, including spacing, of core
`segments, or due to manner in which winding lead wire(s)
`enter and/or exit core recess(es); e.g., passageway(s) are
`preferably employed. It is furthermore preferred that wind
`ing lead wire(s), for example, pass through core(s) in Such
`fashion and at Such location(s) as will Substantially eliminate
`or minimize formation of virtual current loop(s).
`
`BRIEF DESCRIPTION OF DRAWINGS
`0015 These and other features, aspects, and advantages
`of the present invention will become better understood with
`regard to the following description, appended claims, and
`accompanying drawings where:
`0016 FIG. 1 is a perspective view of two windings 110.
`160 in close mutual proximity, the windings 110, 160 being
`centered on an axis of rotation and lying in mutually parallel
`planes that are more or less perpendicular to the axis of
`rotation, which is to say that windings 110, 160 are coaxial
`with the axis of rotation;
`0017 FIG. 2 is a sectional view of windings 110, 160
`shown in FIG. 1, to which has been added in broken line the
`outline of a reluctance-lowering distribution of material 115,
`165 improving mutual inductive coupling between windings
`110, 160 by lowering reluctance of the path taken by
`magnetic flux lines mutually linking windings 110, 160;
`0018 FIG. 3 is a perspective view of windings 110, 160
`shown in FIG. 1 indicating the path of a closed line integral
`around the wires making up windings 110, 160;
`0019 FIG. 4 is a sectional view showing a structure in
`which the winding/core system shown in FIG. 2 is com
`pletely surrounded by a single common shield 104;
`0020 FIG. 5 is a sectional view showing a situation in
`which common shield 104 shown in FIG. 4 has been split
`into two half-shields 120, 170 by shield airgaps 101;
`0021
`FIG. 6 is a sectional view showing a magnetic field
`as would be produced by the winding/core system shown
`and which was used to generate the shield current finite
`element simulation studies of FIGS. 7 through 10;
`0022 FIG. 7 is a sectional view showing a finite element
`simulation to determine where field-canceling currents flow
`when fringing fields emanating from the peripheries of core
`airgaps impinge on either part of a two-part wraparound
`shield having shield airgaps that are adjacent to the core
`airgaps;
`0023 FIG. 8 is a sectional view showing a finite element
`simulation to determine where field-canceling currents flow
`when fringing fields emanating from peripheries of core
`airgaps impinge on the same part of a two-part wraparound
`shield having shield airgaps that are nonadjacent with
`respect to the core airgaps;
`0024 FIG. 9 is a sectional view showing a finite element
`simulation to determine where field-canceling currents flow
`when fringing fields emanating from the periphery of a core
`airgap impinge on a two-part cutback shield having shield
`airgaps that are nonadjacent with respect to the core airgaps;
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 026
`
`

`

`US 2007/0188284 A1
`
`Aug. 16, 2007
`
`FIG. 10 is a sectional view showing a finite element
`0.025
`simulation to determine where field-canceling currents flow
`when fringing fields emanating from peripheries of core
`airgaps impinge on a one-part wraparound shield having a
`shield airgap that is nonadjacent with respect to the core
`airgaps;
`0026 FIG. 11 shows several representative cross-sec
`tional profiles that might be used to generate axisymmetric
`solids of revolution to which the structure of rotary trans
`formers in accordance with embodiments of the present
`invention might conform;
`0027 FIG. 12 is a perspective view of an idealized
`representation of cylindrical configuration 200 such as might
`be constituted or approximated by rotary transformers in
`accordance with embodiments of the present invention;
`0028 FIG. 13 is a meridional section of cylindrical
`configuration 200 shown in FIG. 12;
`0029 FIG. 14 is a perspective view of an idealized
`representation of a planar configuration 300 Such as might
`be constituted or approximated by rotary transformers in
`accordance with embodiments of the present invention;
`0030 FIG. 15 is a meridional section of planar configu
`ration 300 shown in FIG. 14;
`0031
`FIG. 16 is a perspective view of an idealized
`representation of a conical configuration 400 Such as might
`be constituted or approximated by rotary transformers in
`accordance with embodiments of the present invention;
`0032 FIG. 17 is a sectional view of a practical example
`showing how a shielded power coupling device having
`cylindrical configuration may be fabricated through arrange
`ment of multiplicities of ferrite core segments 230, 280 in
`mutually adjacent fashion so as to collectively approximate
`mutually opposed cores which are substantially annular
`and/or semitoroidal;
`0033 FIG. 18 is a side view of a practical example
`showing how a shielded power coupling device having
`planar configuration may be fabricated through arrangement
`of a multiplicity of ferrite core segments 330, 380 in
`mutually adjacent fashion so as to collectively approximate
`mutually opposed cores which are substantially annular
`and/or semitoroidal;
`0034 FIG. 19, in which a power coupling device of
`planar configuration having mutually opposed cores respec
`tively made up of multiplicities of ferrite core segments 330,
`380 as shown in FIG. 18 is drawn as would be seen if viewed
`edge-on within the plane of the paper at FIG. 18, shows how
`lines of magnetic flux bridging core airgap 302 might
`alternately become aligned and misaligned during rotation
`of the power coupling device;
`0035 FIG. 20, in which a power coupling device of
`planar configuration having mutually opposed cores respec
`tively made up of multiplicities of ferrite core segments 330,
`380 as shown in FIG. 18 is drawn in cutaway fashion to
`reveal the windings 310,360 therewithin as would be seen
`if viewed edge-on within the plane of the paper at FIG. 18.
`shows how a virtual current loop 197 might beformed where
`winding lead wires enter and exit a core recess;
`0.036
`FIG. 21, in which ferrite core segments 280 making
`up a portion of the inner core of the power coupling device
`
`having cylindrical configuration shown in FIG. 17 are drawn
`as would be seen if viewed edge-on within the plane of the
`paper at FIG. 17, shows a pair of passageways 277 permit
`ting passage of winding lead wires and disposed in kitty
`corner fashion on mutually adjacent core segments;
`0037 FIG. 22, in which core segments 330 making up a
`portion of the core of one half-couple of the power coupling
`device having planar configuration shown in FIG. 18 are
`drawn in side view as at FIG. 18 except that the core at FIG.
`22 employs E-core segments instead of the C-core segments
`employed in the core at FIG. 18, shows how a three-turn
`winding 310 (here, referring to the winding 310 in the upper
`portion of the drawing) might be routed along a core recess
`such that the winding lead wires enter and exit the core
`recess by way of passageways disposed in kitty-corner
`fashion on mutually adjacent core segments 330;
`0038 FIG. 23 shows several representative cross-sec
`tional profiles that might be used to generate axisymmetric
`solids of revolution to which the structure of rotary trans
`formers in accordance with embodiments of the present
`invention might conform, this drawing in particular demon
`strating how multiple ganged or nested sets of rotary trans
`former half-couples might be incorporated into various
`integral structures.
`
`DETAILED DESCRIPTION
`0039 The present disclosure relates to a shielded power
`coupling device; more particularly, to a shielded power
`coupling device capable of reducing RF emission and/or
`other electromagnetic interference, reducing leakage induc
`tance, and/or improving efficiency during inductive transfer
`of electric power in the context, for example, of a computed
`tomography (CT) scanner Such as might be used in medical
`or security applications or the like, or in the context of other
`such applications where transfer of electric power between
`or among bodies capable of engaging in relative rotation is
`desired.
`0040. As used herein, the terms “electromagnetic inter
`ference.”“radio frequency (RF) emission, and the like can
`in their most general senses include interference from Sur
`rounding equipment as it affects operation of power cou
`pling device(s) in accordance with embodiment(s) of the
`present invention, but such terms are especially intended to
`refer to interference generated by power coupling device(s)
`in accordance with embodiment(s) of the present invention,
`particularly as it would affect sensitive electronic equipment
`Such as might comprise portion(s) of CT scanner(s) or Such
`as might be used in conjunction with CT scanner(s) or other
`Such system(s) in the context of which power coupling
`device(s) in accordance with embodiment(s) of the present
`invention may be used.
`0041 Although the singular may be used herein for
`convenience in introducing terms such as “body.'"object,
`“stator.”“rotor.”“airgap.”“shield,”“core,”“winding,”“cen
`ter.'"axis, etc., a similar situation will of course exist, and
`the present invention should be understood to in general be
`applicable, where plurality or pluralities of one or more of
`Such features is or are present. Conversely, where plurality
`or pluralities are discussed, this is not to necessarily exclude
`the singular. Also, with regard to usage of prepositions
`“between” and “among, except where otherwise clear from
`context, use of “between is not intended to necessarily
`
`Momentum Dynamics Corporation
`Exhibit 1026
`Page 027
`
`

`

`US 2007/0188284 A1
`
`Aug. 16, 2007
`
`imply limitation to two objects, and use of “among is not
`intended to necessarily imply limitation to more than two
`objects.
`0042. Note that the term “noncontact” is used herein to
`refer to the ability to transfer power in inductive fashion
`between or among bodies capable of relative rotation, and
`should not be understood to necessarily preclude possible
`contact between or among such bodies for other purposes,
`including, e.g., electrostatic discharge, exchange or trans
`mission of data, mechanical drive or Support, braking and
`safety mechanisms, low-voltage power transfer, or even
`high-voltage power transfer Such as might be desired in
`addition to power transferred inductively by of the types of
`power coupling device(s) disclosed herein.
`0.043
`Referring to FIG. 1, two more or less circular coils
`of more or less equal diameter comprising electrically
`conductive wire or the like (hereinafter “windings’) 110.
`160 are shown in close mutual proximity, these windings
`110, 160 being centered on an axis of rotation and lying in
`mutually parallel planes that are more or less perpendicular
`to the axis of rotation, which is to say that windings 110, 160
`are coaxial with the axis of rotation. If a torus is imagined
`that is centered on the axis of rotation and that has major
`radius equal to the radius of curvature of the windings, flow
`of electric current along a major circle of the torus will cause
`flow of loops of magnetic flux along minor circles of the
`torus in accordance with the so-called right hand rule (if wire
`is grasped with right hand such that thumb points in direc
`tion of electric current flow, induced magnetic flux will be
`in direction of curl of fingers around wire). Note that no
`attempt has been made in the drawings to accurately portray
`the sense or sign of current or flux flow, i.e., forward/
`backward or clockwise/counterclockwise, the intention here
`only being to indicate paths respectively traversed by elec
`tric current on the one hand and magnetic flux on the other;
`furthermore, where the electric current flowing therethrough
`is an alternating electric current, direction of current and flux
`flow will alternate in time-varying fashion, but no attempt
`has been made to portray this as well. Note that, except
`where otherwise clear from context, “current(s) as used
`herein refers to alternating electric current(s).
`0044 Single-turn windings 110, 160 are shown, but
`either or both of these windings 110, 160 may instead have
`multiple turns or fractional turn(s) (“fractional turn” mean
`ing a turn of less than 360° or having such a fractional
`remainder in addition to a single turn or multiple turns).
`Where windings 110, 160 are in relative rotation with
`respect to each other, a frame of reference may be imagined
`Such that one of the windings appears to be stationary, in
`which case the assembly can be viewed as having a station
`ary side (e.g., at winding 110) and a rotating side (e.g., at
`winding 160) with an airgap therebetween to allow for
`relative motion.
`0045. Note that in the present specification, except where
`otherwise clear from context, the terms 'gap' and “airgap'
`are used more or less interchangeably; although the term
`“airgap' may be used herein, as this should be understood to
`be mere deference to convention, it should be understood
`that Such gaps are not limited to air, it being possible for
`vacuum, oil, and/or other fluid, and/or sliding and/or roller
`bearings or other such contrivance(s) permitting relative
`movement to completely or partially fill Such space(s).
`
`0046 For example, in applications where power must be
`transferred to or from a rotating part, instead of, or in
`addition to, using sliding or rubbing contact(s) (e.g.,
`brush(es) or the like) for electrical connection between
`stationary and rotating sides, it may be convenient to employ
`Such a pair of windings, making electrical connection to
`stationary electronic circuitry via the stationary side, making
`electrical connection to rotating electronic circuitry via the
`rotating side, and transferring power across the airgap ther
`ebetween by mutual induction after the fashion of a trans
`former. In such a case, the two windings 110, 160 will be
`mutually inductively coupled by magnetic flux lines Such
`that when an oscillating electric current is applied to one of
`the windings an electromotive force appears on the other of
`the windings.
`0047 Referring now to FIG. 2, this is a sectional view of
`windings 110, 160 shown in FIG. 1, to which has been added
`in broken line the outline of C-shaped ferromagnetic half
`cores 115, 165 or other such reluctance-lowering distribu
`tion of material improving mutual inductive coupling
`between windings 110, 160 by lowering reluctance of the
`path taken by magnetic flux lines mutually linking windings
`110, 160. Stating this another way, a toroidal shell of ferrite
`(an electrically nonconductive ferromagnetic ceramic mate
`rial) or the like might be placed around windings 110, 160
`in order to increase coupling therebetween; and where it is
`desired that the two windings 110, 160 be capable of moving
`with respect to each other, it will be convenient if this ferrite
`shell is split to allow movement between the one half-core
`which is fixed to the stationary winding 110 and the other
`half-core which moves with the rotating winding 160. In
`Such case, the path taken by a loop of magnetic flux mutually
`linking the two windings 110, 160 will have two segments
`through ferrite and two segments through air.
`0048. Note that as used herein, terms such as “half
`couple.”“half-shell,”“half-core,”“half-shield,” and the like
`are used as shorthand to refer to one of multiple (e.g., two)
`parts making up a whole constituting an inductive couple,
`shell, or the like, and as such should not be interpreted
`overly literally to mean that there must be exactly two such
`components or that such components must be of equal size,
`Volume, mass, or the like; nor should similar implication that
`there must be exactly two such components be drawn from
`use of the term “couple.” Rather, as used herein, except
`where otherwise clear from context, such terms should be
`understood to be representative of the more general case in
`which multiple parts may make up such a whole. Note th