Patents by Inventor Ryuusei FUJITA
Ryuusei FUJITA has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20230369628Abstract: A preferred aspect of the present invention is a fuel cell stack provided with a plurality of fuel cells each including a solid electrolyte layer and first and second electrode layers formed across the solid electrolyte layer. The fuel cells are stacked with the first or second electrode layers of adjacent cells facing each other. A common flow path for supplying a first gas to both of the first electrode layers facing each other is formed in an area where the first electrode layers face each other. A common flow path for supplying a second gas to both of the second electrode layers facing each other is formed in an area where the second electrode layers face each other. A connection electrode is formed at the end of the fuel cell. At least some of the stacked cells are connected in series via the connection electrode.Type: ApplicationFiled: April 26, 2023Publication date: November 16, 2023Inventors: Yoshitaka SASAGO, Noriyuki SAKUMA, Natsuki YOKOYAMA, Ryuusei FUJITA
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Publication number: 20230327164Abstract: An object of the present invention is to provide a fuel cell that obtains high output density and prevents stress application to the cell during stack assembling and breakage. The fuel cell is equipped with a unit cell including a structure in which an electrolyte layer is sandwiched between an anode electrode layer and a cathode electrode layer. The unit cell is disposed between a first member and a second member. An intermediate substrate is disposed between the first member and the second member. The unit cell is supported at the outer peripheral portion thereof by the intermediate substrate. The width of the electrolyte layer is the maximum width or less of a hollow portion formed between at least one of the first member and the second member and the unit cell.Type: ApplicationFiled: February 22, 2023Publication date: October 12, 2023Inventors: Ryuusei FUJITA, Yoshitaka SASAGO, Noriyuki SAKUMA, Natsuki YOKOYAMA
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Patent number: 11296191Abstract: Dielectric breakdown resistance of a power module including a SiC-IGBT and a SiC diode is improved. The power module includes a SiC-IGBT 110 and a SiC diode 111, and a film thickness of a resin layer 323 covering an upper portion of an electric field relaxation region 320 of the SiC-IGBT 110 is larger than a chip thickness of the SiC-IGBT 110, that is, for example, 200 ?m or more.Type: GrantFiled: October 2, 2017Date of Patent: April 5, 2022Assignee: HITACHI, LTD.Inventors: Ryuusei Fujita, Naoki Watanabe, Yuan Bu
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Publication number: 20210351271Abstract: Dielectric breakdown resistance of a power module including a SiC-IGBT and a SiC diode is improved. The power module includes a SiC-IGBT 110 and a SiC diode 111, and a film thickness of a resin layer 323 covering an upper portion of an electric field relaxation region 320 of the SiC-IGBT 110 is larger than a chip thickness of the SiC-IGBT 110, that is, for example, 200 ?m or more.Type: ApplicationFiled: October 2, 2017Publication date: November 11, 2021Inventors: Ryuusei FUJITA, Naoki WATANABE, Yuan BU
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Patent number: 10692860Abstract: An object of the present invention is to increase the reliability of a power module and a power converter and to extend their life. In order to achieve this, a power module includes: two switching devices each including a diode and a transistor, the two switching devices being electrically connected in parallel; and an insulating substrate on which the two switching devices are mounted. Further, a gate electrode of MOFET that each of the two switching device has is electrically connected to a gate resistance. Further, of the two switching devices, the gate resistance that is electrically connected to the switching device, whose current value is smaller when a predetermined voltage is applied in the forward direction of the body diode, is greater than the gate resistance that is electrically connected to the switching device whose current value is larger.Type: GrantFiled: December 12, 2018Date of Patent: June 23, 2020Assignee: HITACHI, LTD.Inventors: Ryuusei Fujita, Kumiko Konishi, Akio Shima
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Patent number: 10511301Abstract: A gate drive circuit to prevent a false turn-on phenomenon includes a first, second, third and fourth switching element, and a capacitor. A source of the first switching element is connected to a first voltage, and a drain of the same is connected to the main switching element's gate electrode. A source of the second switching element is connected to a second voltage, and a drain of the same is connected to the gate electrode. A source of the third switching element is connected to the first voltage, and a drain of the same is connected to a first electrode of the capacitor. A source of the fourth switching element is connected to the second voltage, and a drain of the same is connected to the first electrode and to the drain of the third switching element. A second electrode of the capacitor is connected to the gate electrode.Type: GrantFiled: June 24, 2016Date of Patent: December 17, 2019Assignee: Hitachi, Ltd.Inventors: Satoru Akiyama, Ryuusei Fujita
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Patent number: 10367090Abstract: Provided is a silicon carbide semiconductor device in which SiC-MOSFETs are formed within an active region of an n-type silicon carbide semiconductor substrate, and a p+-type semiconductor region is formed on an upper surface of an epitaxial layer so as to surround the active region.Type: GrantFiled: July 2, 2018Date of Patent: July 30, 2019Assignee: Hitachi, Ltd.Inventors: Kumiko Konishi, Ryuusei Fujita, Kazuki Tani, Akio Shima
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Publication number: 20190198495Abstract: An object of the present invention is to increase the reliability of a power module and a power converter and to extend their life. In order to achieve this, a power module includes: two switching devices each including a diode and a transistor, the two switching devices being electrically connected in parallel; and an insulating substrate on which the two switching devices are mounted. Further, a gate electrode of MOFET that each of the two switching device has is electrically connected to a gate resistance. Further, of the two switching devices, the gate resistance that is electrically connected to the switching device, whose current value is smaller when a predetermined voltage is applied in the forward direction of the body diode, is greater than the gate resistance that is electrically connected to the switching device whose current value is larger.Type: ApplicationFiled: December 12, 2018Publication date: June 27, 2019Inventors: Ryuusei FUJITA, Kumiko KONISHI, Akio SHIMA
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Publication number: 20190115465Abstract: Provided is a silicon carbide semiconductor device in which SiC-MOSFETs are formed within an active region of an n-type silicon carbide semiconductor substrate, and a p+-type semiconductor region is formed on an upper surface of an epitaxial layer so as to surround the active region.Type: ApplicationFiled: July 2, 2018Publication date: April 18, 2019Applicant: HITACHI, LTD.Inventors: Kumiko KONISHI, Ryuusei FUJITA, Kazuki TANI, Akio SHIMA
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Publication number: 20180375509Abstract: A gate drive circuit to prevent a false turn-on phenomenon includes a first, second, third and fourth switching element, and a capacitor. A source of the first switching element is connected to a first voltage, and a drain of the same is connected to the main switching element's gate electrode. A source of the second switching element is connected to a second voltage, and a drain of the same is connected to the gate electrode. A source of the third switching element is connected to the first voltage, and a drain of the same is connected to a first electrode of the capacitor. A source of the fourth switching element is connected to the second voltage, and a drain of the same is connected to the first electrode and to the drain of the third switching element. A second electrode of the capacitor is connected to the gate electrode.Type: ApplicationFiled: June 24, 2016Publication date: December 27, 2018Applicant: HITACHI, LTD.Inventors: Satoru AKIYAMA, Ryuusei FUJITA
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Patent number: 10115700Abstract: The object of the present invention is to compensate for a difference in threshold voltage between a plurality of switching devices incorporated in a power module. The present invention solves the subject described above by mounting a switching device having a high threshold voltage in comparison with a different switching device at a location at which the temperature of the power module during operation is higher than that at another location at which the different switching device is mounted. Eventually, a power conversion apparatus of a high performance and a vehicle drive apparatus of a high performance can be provided.Type: GrantFiled: March 13, 2015Date of Patent: October 30, 2018Assignee: Hitachi, Ltd.Inventors: Ryuusei Fujita, Satoru Akiyama, Hiroshi Kageyama, Toru Masuda, Ayumu Hatanaka, Akio Shima
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Publication number: 20180026009Abstract: The object of the present invention is to compensate for a difference in threshold voltage between a plurality of switching devices incorporated in a power module. The present invention solves the subject described above by mounting a switching device having a high threshold voltage in comparison with a different switching device at a location at which the temperature of the power module during operation is higher than that at another location at which the different switching device is mounted. Eventually, a power conversion apparatus of a high performance and a vehicle drive apparatus of a high performance can be provided.Type: ApplicationFiled: March 13, 2015Publication date: January 25, 2018Inventors: Ryuusei FUJITA, Satoru AKIYAMA, Hiroshi KAGEYAMA, Toru MASUDA, Ayumu HATANAKA, Akio SHIMA