Patents by Inventor Mizuki NAKAHARA
Mizuki NAKAHARA 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: 20240128824Abstract: A dynamo-electric machine comprising: a stator core with plurality of slots, a coil covered with insulated conductor wire, wherein the coil comprising plurality of storages stored in the slots and plurality of coil ends that are outside of the slots, conductor of coil end close to the conductor of the heterophase coil having insulating materials at only one of the surfaces, either the inner diameter surface close to the conductor of the heterophase coil or outer diameter surface of the heterophase coil.Type: ApplicationFiled: December 16, 2021Publication date: April 18, 2024Inventors: Kenji IKEDA, Yuji ENOMOTO, Hirooki TOKOI, Mizuki NAKAHARA, Hiroyuki MIKAMI, Toshifumi SUZUKI, Toru SAKAI, Masaru AMAIKE, Yuji TSUJI
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Publication number: 20240097508Abstract: A rotary electric machine (1000) including: a rotor (200); a stator (100) surrounding a periphery of the rotor (200); a first recessed portion (133) disposed in an inner circumferential surface of a back yoke (130) of the stator (100), and extending in an axial direction of the stator (100); and a tooth (120) having one end fitted in the first recessed portion (133), a clearance formed between the first recessed portion (133) and the one end of the tooth (120) fitted in the first recessed portion (133) being smaller in a circumferential direction of the stator (100) than in a radial direction of the stator (100).Type: ApplicationFiled: November 24, 2021Publication date: March 21, 2024Inventors: Hirooki TOKOI, Mizuki NAKAHARA, Toshifumi SUZUKI, Masaru AMAIKE, Shuuichi TAKAHASHI, Yasuei YONEOKA, Toru SAKAI
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Publication number: 20240055173Abstract: The present invention provides a transformer having a high degree of design freedom for adjusting leakage inductance, while conforming to arrangement constraints between components in order to ensure the insulating properties of the transformer. This transformer has a core formed of a magnetic body, a primary coil wound around the core and being connected to a high-voltage side, the primary coil having two coil layers of an inner primary coil and an outer primary coil arranged more toward an outer peripheral side than the inner primary coil, and a second primary coil wound around the core and connected to a low-voltage side, the outer primary coil being arranged offset with respect to the inner primary coil in the longitudinal direction of the axis of the core.Type: ApplicationFiled: September 27, 2021Publication date: February 15, 2024Applicant: Hitachi, Ltd.Inventors: Kimihisa FURUKAWA, Akihiko KANOUDA, Yuuichi MABUCHI, Mizuki NAKAHARA, Hideaki TANAKA
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Publication number: 20230238897Abstract: A power conversion device capable of shortening the time required for acceleration of a motor and a metal processing device including the power conversion device are provided. Then, a power conversion device 10 includes a converter 100 configured to convert an AC voltage from outside to a DC voltage Vo and a converter controller 107 configured to control the converter 100. The converter 100 includes a voltage doubler circuit 104 configured to boost the DC voltage Vo when activated, and outputs the DC voltage Vo having a voltage value different in accordance with the activation and stop of the voltage doubler circuit 104. The converter controller 107 activates the voltage doubler circuit 104 at a first time that is earlier by a predetermined period than a second time at which a speed command value ?* of the motor 130 rises from a predetermined value.Type: ApplicationFiled: May 27, 2021Publication date: July 27, 2023Inventors: Mizuki NAKAHARA, Hirooki TOKOI, Kenji IKEDA
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Publication number: 20220385204Abstract: A power conversion device and a press apparatus capable of preventing an excessive current in a DC-link capacitor are provided. The power conversion device 10 includes a voltage-doubling rectifier circuit 12. In the voltage-doubling rectifier circuit 12, in a voltage-doubling rectification mode, a common connection node Nc between two capacitors 102a and 102b is connected to a predetermined node. A current detector circuit 107 detects a switching current (IL) flowing in the switching elements SW1 and SW2, and a current detector circuit 108 detects a load current Ild of a load 15. In a mode switching period from a full-wave rectification mode to a voltage-doubling rectification mode, a controller circuit 110 controls the switching of the switching elements SW1 and SW2, based on the switching current (IL) and the load current Ild.Type: ApplicationFiled: April 16, 2020Publication date: December 1, 2022Inventors: Mizuki NAKAHARA, Hirooki TOKOI, Kimihisa FURUKAWA, Yuki KAWAGUCHI
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Patent number: 11296610Abstract: An object of the present invention is to sufficiently reduce a switching loss. A control device causes a positive electrode of a first voltage to appear at a second connection point by switching second and third switching elements to an ON state. Next, the control device causes the positive electrode of the first voltage to appear at a first connection point by switching the second and third switching elements to an OFF state. After that, fifth and eighth switching elements are switched to the OFF state, and sixth and seventh switching elements are switched to the ON state.Type: GrantFiled: December 21, 2016Date of Patent: April 5, 2022Assignee: Hitachi, Ltd.Inventors: Kimihisa Furukawa, Shintaro Tanaka, Takae Shimada, Akihiko Kanouda, Mizuki Nakahara, Yuuichi Mabuchi
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Patent number: 11152870Abstract: A power conversion device that suppresses voltage pulsation of a capacitor of a power converter with respect to a control target whose effective power is to be controlled is provided. The power conversion device includes a plurality of power conversion cells that are connected to each other, and convert a primary-side system voltage into a secondary-side system voltage, a capacitor that is connected to each of the plurality of power conversion cells, and a power conversion cell driver that drives the power conversion cells to add a 3N order higher-harmonic-wave voltage of each of alternating voltages of the plurality of power conversion cells to the each of alternating voltages, and output a voltage made by adding the each of alternating voltages and the 3N order higher-harmonic-wave voltage, when N is a natural number.Type: GrantFiled: October 4, 2018Date of Patent: October 19, 2021Assignee: Hitachi Industrial Products, Ltd.Inventors: Kimihisa Furukawa, Akihiko Kanouda, Yuuichi Mabuchi, Hiroyuki Shoji, Takae Shimada, Mitsuhiro Kadota, Mizuki Nakahara
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Publication number: 20210305903Abstract: An object of the present invention is to sufficiently reduce a switching loss. A control device causes a positive electrode of a first voltage to appear at a second connection point by switching second and third switching elements to an ON state. Next, the control device causes the positive electrode of the first voltage to appear at a first connection point by switching the second and third switching elements to an OFF state. After that, fifth and eighth switching elements are switched to the OFF state, and sixth and seventh switching elements are switched to the ON state.Type: ApplicationFiled: December 21, 2016Publication date: September 30, 2021Inventors: Kimihisa FURUKAWA, Shintaro TANAKA, Takae SHIMADA, Akihiko KANOUDA, Mizuki NAKAHARA, Yuuichi MABUCHI
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Patent number: 11108334Abstract: Provided is a power conversion device which can be configured inexpensively and in which initial charging can be performed quickly. Accordingly, the power conversion device is provided with: a power conversion device cell having a first converter for converting a first AC voltage to a first DC voltage, a second converter for converting the first DC voltage to another voltage, and a first capacitor charged by the first DC voltage; and a control circuit for allowing charging of the first capacitor while changing the operational state of the first converter in accordance with the first DC voltage.Type: GrantFiled: October 18, 2018Date of Patent: August 31, 2021Assignee: Hitachi Industrial Products, Ltd.Inventors: Mizuki Nakahara, Takae Shimada, Kimihisa Furukawa, Mitsuhiro Kadota
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Publication number: 20210167690Abstract: Provided is a power conversion device which can be configured inexpensively and in which initial charging can be performed quickly. Accordingly, the power conversion device is provided with: a power conversion device cell having a first converter for converting a first AC voltage to a first DC voltage, a second converter for converting the first DC voltage to another voltage, and a first capacitor charged by the first DC voltage; and a control circuit for allowing charging of the first capacitor while changing the operational state of the first converter in accordance with the first DC voltage.Type: ApplicationFiled: October 18, 2018Publication date: June 3, 2021Inventors: Mizuki NAKAHARA, Takae SHIMADA, Kimihisa FURUKAWA, Mitsuhiro KADOTA
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Publication number: 20210044212Abstract: A power conversion device that suppresses voltage pulsation of a capacitor of a power converter with respect to a control target whose effective power is to be controlled is provided. The power conversion device includes a plurality of power conversion cells that are connected to each other, and convert a primary-side system voltage into a secondary-side system voltage, a capacitor that is connected to each of the plurality of power conversion cells, and a power conversion cell driver that drives the power conversion cells to add a 3N order higher-harmonic-wave voltage of each of alternating voltages of the plurality of power conversion cells to the each of alternating voltages, and output a voltage made by adding the each of alternating voltages and the 3N order higher-harmonic-wave voltage, when N is a natural number.Type: ApplicationFiled: October 4, 2018Publication date: February 11, 2021Inventors: Kimihisa FURUKAWA, Akihiko KANOUDA, Yuuichi MABUCHI, Hiroyuki SHOJI, Takae SHIMADA, Mitsuhiro KADOTA, Mizuki NAKAHARA
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Patent number: 10615715Abstract: In a power conversion device, a power conversion unit includes a single-phase inverter on a secondary side of a resonant type converter that has an input of a direct current. A power conversion unit group is configured by connecting outputs of the single-phase inverters of a plurality of power conversion units in series. Respective phases of three phase alternate current are formed with the three power conversion unit groups housed in a power conversion device housing. The plurality of power conversion units constituting the power conversion unit group are disposed along a longitudinal direction of the power conversion device housing. The respective three power conversion unit groups are disposed at an upper stage, a middle stage, and a lower stage in a height direction of the power conversion device housing. The power conversion device housing has one end side in the longitudinal direction as output terminals of the three power conversion unit groups.Type: GrantFiled: September 6, 2016Date of Patent: April 7, 2020Assignee: Hitachi, Ltd.Inventors: Yasuaki Norimatsu, Akihiko Kanouda, Yuuichi Mabuchi, Takae Shimada, Mitsuhiro Kadota, Yuki Kawaguchi, Mizuki Nakahara, Akira Yonekawa
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Patent number: 10530271Abstract: In a power conversion device in a configuration in which a plurality of power converter cells has serially connected outputs and includes a converter and an inverter as components, when a load is light, the cells also operate with a light load, and efficiency is reduced. A power conversion device has a plurality of power converter cells. The outputs of the cells are connected in series. The device has a controller that controls the cells. The cells each have a converter that converts an externally inputted power supply voltage and generates a DC link voltage and an inverter that converts the DC link voltage into an alternating current voltage and outputs the current. The controller stops a converter in some of the cells depending on power supply electric power or load electric power. The inverter continues to operate using a link capacitor as a power supply.Type: GrantFiled: April 10, 2017Date of Patent: January 7, 2020Assignee: Hitachi, Ltd.Inventors: Mizuki Nakahara, Yasuaki Norimatsu, Takae Shimada, Mitsuhiro Kadota, Yuki Kawaguchi
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Publication number: 20190319548Abstract: In a power conversion device in a configuration in which a plurality of power converter cells has serially connected outputs and includes a converter and an inverter as components, when a load is light, the cells also operate with a light load, and efficiency is reduced. A power conversion device has a plurality of power converter cells. The outputs of the cells are connected in series. The device has a controller that controls the cells. The cells each have a converter that converts an externally inputted power supply voltage and generates a DC link voltage and an inverter that converts the DC link voltage into an alternating current voltage and outputs the current. The controller stops a converter in some of the cells depending on power supply electric power or load electric power. The inverter continues to operate using a link capacitor as a power supply.Type: ApplicationFiled: April 10, 2017Publication date: October 17, 2019Inventors: Mizuki NAKAHARA, Yasuaki NORIMATSU, Takae SHIMADA, Mitsuhiro KADOTA, Yuki KAWAGUCHI
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Publication number: 20190199238Abstract: In a power conversion device, a power conversion unit includes a single-phase inverter on a secondary side of a resonant type converter that has an input of a direct current. A power conversion unit group is configured by connecting outputs of the single-phase inverters of a plurality of power conversion units in series. Respective phases of three phase alternate current are formed with the three power conversion unit groups housed in a power conversion device housing. The plurality of power conversion units constituting the power conversion unit group are disposed along a longitudinal direction of the power conversion device housing. The respective three power conversion unit groups are disposed at an upper stage, a middle stage, and a lower stage in a height direction of the power conversion device housing. The power conversion device housing has one end side in the longitudinal direction as output terminals of the three power conversion unit groups.Type: ApplicationFiled: September 6, 2016Publication date: June 27, 2019Inventors: Yasuaki NORIMATSU, Akihiko KANOUDA, Yuuichi MABUCHI, Takae SHIMADA, Mitsuhiro KADOTA, Yuki KAWAGUCHI, Mizuki NAKAHARA, Akira YONEKAWA