Patents by Inventor Kimihisa Furukawa

Kimihisa Furukawa 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).

  • Patent number: 11984816
    Abstract: 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: Grant
    Filed: April 16, 2020
    Date of Patent: May 14, 2024
    Assignee: Hitachi Industrial Equipment Systems Co., Ltd.
    Inventors: Mizuki Nakahara, Hirooki Tokoi, Kimihisa Furukawa, Yuki Kawaguchi
  • Publication number: 20240055173
    Abstract: 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: Application
    Filed: September 27, 2021
    Publication date: February 15, 2024
    Applicant: Hitachi, Ltd.
    Inventors: Kimihisa FURUKAWA, Akihiko KANOUDA, Yuuichi MABUCHI, Mizuki NAKAHARA, Hideaki TANAKA
  • Publication number: 20240030824
    Abstract: An aspect of the present disclosure is a power conversion device including: a primary-side transformer to which a primary AC voltage is input from a primary-side circuit; and a secondary-side transformer that outputs a secondary AC voltage lower than the primary AC voltage to a secondary-side circuit. The primary-side transformer includes a primary-side primary winding to which the primary AC voltage is input, and a primary-side secondary winding to which power is transmitted from the primary-side primary winding. The secondary-side transformer includes a secondary-side primary winding constituting a closed circuit together with the primary-side secondary winding, and a secondary-side secondary winding to which power is transmitted from the secondary-side primary winding and which outputs the secondary AC voltage. The primary-side circuit and the closed circuit are connected to a common potential.
    Type: Application
    Filed: July 14, 2023
    Publication date: January 25, 2024
    Inventors: Kimihisa FURUKAWA, Yuuichi MABUCHI, Takae SHIMADA, Mohammed Mosaddique Nawaz HUSSAIN, Hiroshi KAMIZUMA, Yuki KAWAGUCHI, Abhijit CHOUDHURY, Akihiko KANOUDA
  • Publication number: 20230056704
    Abstract: Provided is a power conversion system that can suppress a fault in a short-circuiting switch that bypasses a fault unit and enhance the reliability and redundancy of the system. The power conversion system is provided with a plurality of power converter units that are formed by using semiconductor switch elements and are connected in series, and comprises: switch elements that are provided to input terminals and/or output terminals of the power converter units and bypass the power converter units; and overvoltage suppressing elements which are connected in parallel with the switch elements and in which conducting states are changed by an application of a prescribed voltage.
    Type: Application
    Filed: February 25, 2021
    Publication date: February 23, 2023
    Inventors: Hajime URAI, Hiroshi KAMIZUMA, Kimihisa FURUKAWA, Noriya NAKAO, Kinya NAKATSU
  • Publication number: 20220385204
    Abstract: 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: Application
    Filed: April 16, 2020
    Publication date: December 1, 2022
    Inventors: Mizuki NAKAHARA, Hirooki TOKOI, Kimihisa FURUKAWA, Yuki KAWAGUCHI
  • Patent number: 11296610
    Abstract: 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: Grant
    Filed: December 21, 2016
    Date of Patent: April 5, 2022
    Assignee: Hitachi, Ltd.
    Inventors: Kimihisa Furukawa, Shintaro Tanaka, Takae Shimada, Akihiko Kanouda, Mizuki Nakahara, Yuuichi Mabuchi
  • Patent number: 11201559
    Abstract: The power conversion device includes multiple converter cells. Each converter cell includes a pair of primary-side terminals and a pair of secondary-side terminals. The converter cell transmits power between the pair of primary-side terminals and the pair of secondary-side terminals. The primary-side terminals of the multiple converter cells are connected in series to a primary-side power supply system. The secondary-side terminals of the multiple converter cells are connected in series to a secondary-side power supply system. Among the multiple converter cells, the converter cell in which an absolute value of a ground voltage appearing in the pair of primary-side terminals is the highest is different from the converter cell in which an absolute value of a ground voltage appearing in the pair of secondary-side terminals is the highest.
    Type: Grant
    Filed: June 14, 2017
    Date of Patent: December 14, 2021
    Assignee: Hitachi, Ltd.
    Inventors: Kimihisa Furukawa, Yuuichi Mabuchi, Yuki Kawaguchi, Akihiko Kanouda
  • Patent number: 11152870
    Abstract: 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: Grant
    Filed: October 4, 2018
    Date of Patent: October 19, 2021
    Assignee: Hitachi Industrial Products, Ltd.
    Inventors: Kimihisa Furukawa, Akihiko Kanouda, Yuuichi Mabuchi, Hiroyuki Shoji, Takae Shimada, Mitsuhiro Kadota, Mizuki Nakahara
  • Publication number: 20210305903
    Abstract: 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: Application
    Filed: December 21, 2016
    Publication date: September 30, 2021
    Inventors: Kimihisa FURUKAWA, Shintaro TANAKA, Takae SHIMADA, Akihiko KANOUDA, Mizuki NAKAHARA, Yuuichi MABUCHI
  • Patent number: 11108334
    Abstract: 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: Grant
    Filed: October 18, 2018
    Date of Patent: August 31, 2021
    Assignee: Hitachi Industrial Products, Ltd.
    Inventors: Mizuki Nakahara, Takae Shimada, Kimihisa Furukawa, Mitsuhiro Kadota
  • Publication number: 20210167690
    Abstract: 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: Application
    Filed: October 18, 2018
    Publication date: June 3, 2021
    Inventors: Mizuki NAKAHARA, Takae SHIMADA, Kimihisa FURUKAWA, Mitsuhiro KADOTA
  • Patent number: 11016138
    Abstract: A diagnostic system for a power conversion apparatus including a semiconductor device and performing a switching operation for carrying and interrupting a main current to a main current is disclosed. This system includes a trigger circuit that acquires reference time for the switching operation; and a delay time calculation circuit that acquires first time at which the main current takes a first main current set value and second time at which the main current takes a second main current set value, and that detects numerical data about a difference between the first time and the reference time and numerical data about a difference between the second time and the reference time.
    Type: Grant
    Filed: May 9, 2016
    Date of Patent: May 25, 2021
    Assignee: Hitachi, Ltd.
    Inventors: Yoshinobu Kimura, Junichi Sakano, Kimihisa Furukawa, Takashi Ogawa, Renichi Yamada
  • Publication number: 20210143744
    Abstract: The power conversion device includes multiple converter cells. Each converter cell includes a pair of primary-side terminals and a pair of secondary-side terminals. The converter cell transmits power between the pair of primary-side terminals and the pair of secondary-side terminals. The primary-side terminals of the multiple converter cells are connected in series to a primary-side power supply system. The secondary-side terminals of the multiple converter cells are connected in series to a secondary-side power supply system. Among the multiple converter cells, the converter cell in which an absolute value of a ground voltage appearing in the pair of primary-side terminals is the highest is different from the converter cell in which an absolute value of a ground voltage appearing in the pair of secondary-side terminals is the highest.
    Type: Application
    Filed: June 14, 2017
    Publication date: May 13, 2021
    Inventors: Kimihisa FURUKAWA, Yuuichi MABUCHI, Yuki KAWAGUCHI, Akihiko KANOUDA
  • Publication number: 20210044212
    Abstract: 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: Application
    Filed: October 4, 2018
    Publication date: February 11, 2021
    Inventors: Kimihisa FURUKAWA, Akihiko KANOUDA, Yuuichi MABUCHI, Hiroyuki SHOJI, Takae SHIMADA, Mitsuhiro KADOTA, Mizuki NAKAHARA
  • Patent number: 10425025
    Abstract: Magnetic flux generated when a current flows through a main circuit wiring serves as disturbance of a magnetic sensor, and accurate rotor position information is obtained.
    Type: Grant
    Filed: June 27, 2016
    Date of Patent: September 24, 2019
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Takuro Kanazawa, Kimihisa Furukawa
  • Patent number: 10348218
    Abstract: An object of the invention is to simultaneously solve a miniaturization and an improvement of productivity of a power conversion device, a temperature rise suppression of a smoothing capacitor, and a reduction of motor noises. The power conversion device of the invention includes a smoothing capacitor, a first power conversion unit and a second power conversion unit which are connected in parallel, and a control unit which generates a PWM pulse on the basis of an output voltage vector and a PWM carrier. The control unit includes a correction unit which corrects a predetermined output voltage vector value to two or more different output voltage vector values such that an average value in one period of the PWM carrier becomes the predetermined output voltage vector value. The correction unit corrects a first output voltage vector value in a first period, and corrects a second output voltage vector value in a second period different from the first period.
    Type: Grant
    Filed: September 16, 2015
    Date of Patent: July 9, 2019
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Takuro Kanazawa, Kimihisa Furukawa, Shigehisa Aoyagi
  • Publication number: 20190146026
    Abstract: A diagnostic system for a power conversion apparatus including a semiconductor device and performing a switching operation for carrying and interrupting a main current to a main current is disclosed. This system includes a trigger circuit that acquires reference time for the switching operation; and a delay time calculation circuit that acquires first time at which the main current takes a first main current set value and second time at which the main current takes a second main current set value, and that detects numerical data about a difference between the first time and the reference time and numerical data about a difference between the second time and the reference time.
    Type: Application
    Filed: May 9, 2016
    Publication date: May 16, 2019
    Inventors: Yoshinobu KIMURA, Junichi SAKANO, Kimihisa FURUKAWA, Takashi OGAWA, Renichi YAMADA
  • Patent number: 10122296
    Abstract: A diagnostic system for a power converter which includes a semiconductor device, and which performs a switching operation between conduction and interruption of the principal current flowing through a main circuit. The diagnostic system includes a current change amount calculation circuit for obtaining numeric data which reflects a current change amount of the principal current per unit time, a determination circuit for determining a state of the power converter by comparing the numeric data with a reference value, and an output circuit for outputting a determination result of the determination circuit.
    Type: Grant
    Filed: June 22, 2015
    Date of Patent: November 6, 2018
    Assignee: HITACHI, LTD.
    Inventors: Junichi Sakano, Kimihisa Furukawa, Takashi Ogawa, Hisashi Endou
  • Patent number: 10122299
    Abstract: The present invention relates to a power conversion device in the power electronics field. An object of the present invention is to provide a technique of determining whether a switching element operates normally or not from a gate monitor signal of a power conversion device, and predicting a sign of a failure by obtaining the temperature of the switching element from a transient state of the switching voltage of the power conversion circuit as a component of the power conversion device without using a new signal path.
    Type: Grant
    Filed: April 8, 2015
    Date of Patent: November 6, 2018
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Ogawa, Kimihisa Furukawa, Junichi Sakano
  • Publication number: 20180183369
    Abstract: Magnetic flux generated when a current flows through a main circuit wiring serves as disturbance of a magnetic sensor, and accurate rotor position information is obtained.
    Type: Application
    Filed: June 27, 2016
    Publication date: June 28, 2018
    Inventors: Takuro KANAZAWA, Kimihisa FURUKAWA