Author
Akiyoshi Uchida
Bio: Akiyoshi Uchida is an academic researcher from Fujitsu. The author has contributed to research in topics: Electromagnetic coil & Power transmission. The author has an hindex of 15, co-authored 105 publications receiving 1408 citations.
Papers published on a yearly basis
Papers
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Patent•
23 Jul 2009TL;DR: In this article, a power transmission device includes a power supply unit configured to supply power by a resonance frequency for magnetic resonance; a temperature detector provided in the power transmission resonance coil; and a control unit that can determine whether a detected temperature detected by the temperature detector at an elapsed time is within the allowable temperature range at the elapsed time.
Abstract: A power transmission device includes a power supply unit configured to supply power by a resonance frequency for magnetic resonance; a power transmission resonance coil capable of magnetic resonance with a power reception resonance coil in the resonance frequency, the power transmission resonance coil being configured to supply the power from the power supply unit as magnetic field energy caused by the magnetic resonance; a temperature detector provided in the power transmission resonance coil; and a control unit configured to refer to a table stored in a memory expressing an allowable temperature range, determine whether a detected temperature detected by the temperature detector at an elapsed time is within the allowable temperature range at the elapsed time, and stop an operation of the power supply unit when the detected temperature is not within the allowable temperature range.
246 citations
Patent•
24 Mar 2010TL;DR: In this article, a distance detector was used to detect a distance between the power transmitting resonant coil and the power receiving resonant coils, and a power transmitting frequency controller was used for changing the first resonant frequency of a power receiving coil from the first resonance frequency to a second resonance frequency on the basis of the distance detected by the distance detector.
Abstract: A wireless power supply includes: a power transmitting coil resonant at a first resonant frequency that generates a magnetic field resonance, a power receiving coil resonant at the first resonant frequency, a power receiving unit that outputs energy received by the power receiving resonant coil; a distance detector that detects a distance between the power transmitting resonant coil and the power receiving resonant coil; a power transmitting frequency controller that changes the first resonant frequency to a second resonant frequency on the basis of the distance detected by the distance detector; and a power receiving frequency controller that changes the first resonant frequency of the power receiving resonant coil from the first resonant frequency to a second resonant frequency on the basis of the distance detected by the distance detector.
200 citations
Patent•
30 Mar 2009TL;DR: A wireless power supply system includes a wireless power transmitting device, a power transmission control unit, and a plurality of wireless power receiving devices configured to include respective unique resonant circuits having different resonant frequency characteristics which are different to each other as discussed by the authors.
Abstract: A wireless power supply system includes: a wireless power transmitting device configured to include a variable resonant circuit having a variable-controllable resonant frequency characteristic, and to transmit electric power wirelessly via the variable resonant circuit; a power transmission control unit configured to variably control the resonant frequency characteristic of the variable resonant circuit; and a plurality of wireless power receiving devices configured to include respective unique resonant circuits having respective unique resonant frequency characteristics which are different to each other, and to wirelessly receive power from the wireless power transmitting device by a magnetic field resonance mode arising as a result of the unique resonant circuit tuning to a resonant frequency of the variable resonant circuit
144 citations
Patent•
29 Mar 2010TL;DR: A wireless electric power supply method includes: supplying electric power from a power supply section to a power-transmission resonance coil at a resonance frequency which causes magnetic field resonance as mentioned in this paper.
Abstract: A wireless electric power supply method includes: supplying electric power from a power supply section to a power-transmission resonance coil at a resonance frequency which causes magnetic field resonance; transmitting the electric power, supplied from the power supply section, as magnetic field energy from the power-transmission resonance coil to a power-reception resonance coil by using the magnetic field resonance, the power-transmission resonance coil being capable of being in magnetic field resonance with the power-reception resonance coil at the resonance frequency; monitoring the electric power supply by using a monitor section; comparing, by using a comparison section, the monitoring result obtained by the monitor section with characteristics data indicating the characteristics of the electric power supply performed by the power supply section; and controlling, by using a control section, the electric power supply performed by the power supply section, on the basis of the comparison result obtained by the comparison section.
111 citations
Patent•
31 Mar 2009TL;DR: In this article, a wireless power supply system capable of preventing a decrease in transmission efficiency of power from a power transmission device to a power reception device is provided, where the distance detection unit 14 detects the distance between the power transmission resonance coil 12 and the power reception resonance coil 22.
Abstract: A wireless power supply system capable of preventing a decrease in transmission efficiency of power from a power transmission device to a power reception device is provided. A power transmission resonance coil transmits power as magnetic field energy using magnetic field resonance. The power receiving resonance coil 22 receives the magnetic field energy transmitted from the power transmission resonance coil 12 using magnetic field resonance. The distance detection unit 14 detects the distance between the power transmission resonance coil 12 and the power reception resonance coil 22. The power transmission frequency control unit 13 changes the resonance frequency of the power transmission resonance coil 12 to a value determined based on the distance detected by the distance detection unit 14. The power receiving frequency control unit 23 determines a resonance frequency of the power receiving resonance coil 22 based on the distance detected by the distance detection unit 14, and is the same value as the changed resonance frequency value of the power transmission resonance coil 12. change. [Selection] Figure 1
37 citations
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Patent•
25 Sep 2009
TL;DR: In this paper, improved capabilities for a source resonator having a Q-factor Q 1 >100 and a characteristic size x 1 coupled to an energy source, and a second resonator with a Q -factor Q 2 >100 coupled to a drain located a distance D from the source, where the source and the second resonators are coupled to exchange energy wirelessly among the source this paper.
Abstract: Described herein are improved capabilities for a source resonator having a Q-factor Q 1 >100 and a characteristic size x 1 coupled to an energy source, and a second resonator having a Q-factor Q 2 >100 and a characteristic size x 2 coupled to an energy drain located a distance D from the source resonator, where the source resonator and the second resonator are coupled to exchange energy wirelessly among the source resonator and the second resonator.
535 citations
Patent•
19 Jul 2013
TL;DR: In this article, the authors describe improved configurations for a wireless power converter that includes at least one receiving magnetic resonator configured to capture electrical energy received wirelessly through a first oscillating magnetic field characterized by a first plurality of parameters.
Abstract: Described herein are improved configurations for a wireless power converter that includes at least one receiving magnetic resonator configured to capture electrical energy received wirelessly through a first oscillating magnetic field characterized by a first plurality of parameters, and at least one transferring magnetic resonator configured to generate a second oscillating magnetic field characterized by a second plurality of parameters different from the first plurality of parameters, wherein the electrical energy from the at least one receiving magnetic resonator is used to energize the at least one transferring magnetic resonator to generate the second oscillating magnetic field.
471 citations
Patent•
14 May 2009TL;DR: In this paper, an apparatus for use in wireless energy transfer is described, which includes a first resonator structure configured for energy transfer with a second resonance structure over a distance D larger than characteristic sizes of the first and second resonator structures.
Abstract: Disclosed is an apparatus for use in wireless energy transfer, which includes a first resonator structure configured for energy transfer with a second resonator structure over a distance D larger than characteristic sizes, [insert formula] and [insert formula], of the first and second resonator structures. A power generator is coupled to the first structure and configured to drive the first resonator structure or the second resonator structure at an angular frequency away from the resonance angular frequencies and shifted towards a frequency corresponding to an odd normal mode for the resonator structures to reduce radiation from the resonator structures by destructive far-field interference.
442 citations
Patent•
21 Jun 2013
TL;DR: A variable type magnetic resonator as discussed by the authors includes an array of resonators each having one of at least two substantially different magnetic dipole moment orientations and at least one power and control circuit configured to selectively connect to and energize one of the resonators.
Abstract: A variable type magnetic resonator includes an array of resonators each having one of at least two substantially different magnetic dipole moment orientations and at least one power and control circuit configured to selectively connect to and energize at least one of the array of resonators.
415 citations
Patent•
10 Mar 2010
TL;DR: In this article, improved configurations for a device for wireless power transfer that includes a conductor forming at least one loop of a high-Q resonator, a capacitive part electrically coupled to the conductor, and a power and control circuit was presented.
Abstract: Described herein are improved configurations for a device for wireless power transfer that includes a conductor forming at least one loop of a high-Q resonator, a capacitive part electrically coupled to the conductor, and a power and control circuit electrically coupled to the conductor, the power and control circuit providing two or more modes of operation and the power and control circuit selecting how the high-Q resonator receives and generates an oscillating magnetic field.
410 citations