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John Talbot Boys

Bio: John Talbot Boys is an academic researcher. The author has contributed to research in topics: Capacitor & Inductor. The author has an hindex of 11, co-authored 13 publications receiving 1331 citations.

Papers
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Patent
05 Feb 1992
TL;DR: In this paper, a contactless inductive power distribution system operating at 10 KHz has a self tuning resonant power supply connected to a resonant primary conductive path (10110, 10111) comprising a pair of parallel litz wire conductors, each encapsulated within an insulated sheath and supported on a structural monorail beam.
Abstract: A contactless inductive power distribution system operating at 10 KHz has a self tuning resonant power supply connected to a resonant primary conductive path (10110, 10111) comprising a pair of parallel litz wire conductors (10110, 10111) each encapsulated within an insulated sheath and supported on a structural monorail beam (10101) on which a plurality of electric vehicles can run. Each vehicle has an electric motor (not shown) capable of deriving power from a resonant pick-up coil (10115) wound on a ferrite core (10102) mounted on the vehicle in close proximity to the primary conductors (10110, 10111). Each vehicle also has switching means (10116) capable of preventing a lightly loaded vehicle from presenting a reduced load to the resonant primary. As shown, this comprises an isolating coil (10116) having a switch (not shown) to switch the coil between an open circuit and a short circuit, so that when the switch is switched from one state to another state the power coupled between the primary conductive path (10110, 10111) and the pick-up coil (10115) is changed.

409 citations

Patent
20 Oct 1994
TL;DR: In this paper, a loosely coupled inductive power transfer system suitable for transferring power to a mobile conveyer platform or a vehicle has pick-up coils wound on flux concentrator(s).
Abstract: A loosely coupled inductive power transfer system suitable for transferring power to a mobile conveyer platform or a vehicle has pick-up coils wound on flux concentrator(s). One or more large flat horizontal ferrite cores (607, 608) are used to concentrate the horizontal component of magnetic flux from an extended volume into one or more secondary or pick-up coils (613). Each shock-resistant core comprises an array of many individual strips of ferrite held in close contact. One, more usually two, or perhaps more resonant pick-up windings are wound about each core and each winding has a shorting switch (within 602, 603, ...) placed across it. A controller (601) connects a controlled output voltage on to an output bus (605, 606) from the best-placed pick-up winding on any one core at any moment, while holding the others in a shorted hence inactive state.

251 citations

Patent
11 Jul 1995
TL;DR: In this article, an inductive coupling of power to devices having negative resistances, such as gas-filled discharge lamps (fluorescent tubes, neon signs, and the like) from a primary inductive loop, using resonant conditioning of the power provided to the device was discussed.
Abstract: Disclosed is inductive coupling of power to devices having negative resistances, such as gas-filled discharge lamps (fluorescent tubes, neon signs, and the like) from a primary inductive loop, using resonant conditioning of the power provided to the device. A "C" shaped inductor (202) around the loop and a resonating capacitor (406) in parallel with the inductor provide a current source to the lamp (403) from across the capacitor. The circuit is capable of first igniting a lamp using a higher voltage available when the Q of the unloaded circuit is high, then running the lamp or other device at a controlled current. The lamp current is substantially proportional to the primary inductive loop flux, and substantially independent of the lamp resistance. A second inductor (404) in series with the first though not itself a collector of flux acts as a current limit. Applications include lighting, displays (optionally isolated and dimmable), and production of ultraviolet radiation.

148 citations

Patent
12 Feb 2001
TL;DR: An inductively powered lamp unit 806 is fixed onto a substrate and over a position where a primary inductive loop 803 is spread apart (as at 807). At such sites, a horizontal component of alternating magnetic flux is available as discussed by the authors.
Abstract: An inductively powered lamp unit 806 is fixed onto a substrate and over a position where a primary inductive loop 803 is spread apart (as at 807). At such sites, a horizontal (or at least parallel to the surface of the substrate) component of alternating magnetic flux is available. The conductors of the loop 802-803 can be inserted in a slit 804 cut into the substrate. The spreading apart of the conductors may be ensured with a spreader 808. A power supply 801 may be a resonant supply operating at 40 kHz. The lamp unit 806 does use a resonant pickup coil which can be shorted so as to minimize coupling, and provide supply regulation. The lamp unit can be controlled by signals transmitted over the primary loop. Applications include roadway markers and fire escape egress indicators, and underwater lighting.

143 citations

Patent
05 Aug 1992
TL;DR: A phase-splitting transformer provides, via a decoupling inductor, one connection for a power supply; the return is through the active switches, which are either off or are from time to time driven alternately by the controller as discussed by the authors.
Abstract: This resonant power supply produces a varying magnetic field from a resonant inductor. Two active switches drive, but remain outside, a resonant circuit, also including resonant capacitor. A phase-splitting transformer provides, via a decoupling inductor, one connection for a power supply; the return is through the active switches, which are either off or are from time to time driven alternately by the controller so as to maintain the resonant current in the resonant circuit. Applications include induction heating and induction hobs for cooking, and also a power source for inductively powered vehicles (or other inductively powered devices) adjacent to an inductive pathway.

136 citations


Cited by
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Patent
28 Feb 2001
TL;DR: In this article, radio frequency energy is used to both temporarily stun tissue and to ablate tissue through a common electrode, which can be accomplished by tissue ablation or by the administration of medication.
Abstract: Systems and methods for diagnosing and treating tissue transmit an electrical energy pulse that temporarily stuns a zone of tissue, temporarily rendering it electrically unresponsive. The systems and methods sense an electrophysiological effect due to the transmitted pulse. The systems and methods alter an electrophysiological property of tissue in or near the zone based, at least in part, upon the sensed electrophysiological effect. The alteration of the electrophysiological property can be accomplished, for example, by tissue ablation or by the administration of medication. In a preferred implementation, radio frequency energy is used to both temporarily stun tissue and to ablate tissue through a common electrode.

1,098 citations

Patent
18 Dec 2008
TL;DR: The paper looks at the background to IPT and how its development was based on sound engineering principles leading on to factory automation and growing to a $1 billion industry in the process.
Abstract: A detection method for use in a primary unit of an inductive power transfer system, the primary unit being operable to transmit power wirelessly by electromagnetic induction to at least one secondary unit of the system located in proximity to the primary unit and/or to a foreign object located in said proximity, the method comprising: driving the primary unit so that in a driven state the magnitude of an electrical drive signal supplied to one or more primary coils of the primary unit changes from a first value to a second value; assessing the effect of such driving on an electrical characteristic of the primary unit; and detecting in dependence upon the assessed effect the presence of a said secondary unit and/or a foreign object located in proximity to said primary unit.

969 citations

Patent
13 May 2003
TL;DR: In this paper, a system and method for transferring power without requiring direct electrical conductive contacts is described, where a primary unit having a power supply and a substantially laminar charging surface having at least one conductor that generates an electromagnetic field when a current flows there through and having an charging area defined within a perimeter of the surface, the at least conductor being arranged such that electromagnetic field lines generated by the at most one conductor are substantially parallel to the plane of the ground surface or at least subtend an angle of 45° or less to the surface within the charging area.
Abstract: There is disclosed a system and method for transferring power without requiring direct electrical conductive contacts. There is provided a primary unit having a power supply and a substantially laminar charging surface having at least one conductor that generates an electromagnetic field when a current flows therethrough and having an charging area defined within a perimeter of the surface, the at least one conductor being arranged such that electromagnetic field lines generated by the at least one conductor are substantially parallel to the plane of the surface or at least subtend an angle of 45° or less to the surface within the charging area; and at least one secondary device including at least one conductor that may be wound about a core. Because the electromagnetic field is spread over the charging area and is generally parallel or near-parallel thereto, coupling with flat secondary devices such as mobile telephones and the like is significantly improved in various orientations thereof.

886 citations

Patent
11 Jun 2007
TL;DR: In this paper, a first resonator structure configured to transfer energy non-radiatively with a second resonance structure over a distance greater than a characteristic size of the second resonator.
Abstract: Disclosed is an apparatus for use in wireless energy transfer, which includes a first resonator structure configured to transfer energy non-radiatively with a second resonator structure over a distance greater than a characteristic size of the second resonator structure. The non-radiative energy transfer is mediated by a coupling of a resonant field evanescent tail of the first resonator structure and a resonant field evanescent tail of the second resonator structure.

856 citations

Patent
05 Jul 2006
TL;DR: In this paper, the authors proposed an electromagnetic energy transfer device that includes a first resonator structure receiving energy from an external power supply, and a second resonance structure is positioned distal from the first, and supplies useful working power to an external load.
Abstract: The electromagnetic energy transfer device includes a first resonator structure receiving energy from an external power supply. The first resonator structure has a first Q-factor. A second resonator structure is positioned distal from the first resonator structure, and supplies useful working power to an external load. The second resonator structure has a second Q-factor. The distance between the two resonators can be larger than the characteristic size of each resonator. Non-radiative energy transfer between the first resonator structure and the second resonator structure is mediated through coupling of their resonant-field evanescent tails.

730 citations