Patents by Inventor Kikuo Izumi

Kikuo Izumi 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: 11025086
    Abstract: The power conversion device includes common DC buses, AC buses, DC connection terminals, AC connection terminals, N pairs of distributed power supply connection terminals, N DC/DC converters for transferring power between the common DC buses and the distributed power supply connection terminals, M DC/AC converters for transferring power between the AC buses and the common DC buses, and a control unit for controlling each converter on the basis of a high-order control command. The DC connection terminals are connected to the common DC buses and connected to an external DC power distribution grid, the AC connection terminals are connected to the AC buses and connected to an external AC power distribution grid, and the distributed power supply connection terminals are connected to the DC/DC converters and connected to external DC distributed power supplies.
    Type: Grant
    Filed: April 16, 2020
    Date of Patent: June 1, 2021
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Akiko Tabuchi, Kikuo Izumi, Naohisa Kawahara, Daigo Takemura
  • Patent number: 10971991
    Abstract: A controller of each power conversion device in a power conversion system controls a switching element unit, based on a detected value of reactor current flowing through a filter reactor, a detected value of output voltage output between the terminals of a filter capacitor, and a detected value of output current flowing through an output reactor. The controller generates a voltage command based on the output current and the output voltage and generates a correction amount of the voltage command based on the output current in which a reference frequency component is removed. The controller generates a current command based on the addition value of the voltage command and the correction amount and controls the switching element unit such that the reactor current matches the current command.
    Type: Grant
    Filed: February 19, 2018
    Date of Patent: April 6, 2021
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Takahiro Kato, Kikuo Izumi, Akiko Tabuchi
  • Patent number: 10924035
    Abstract: A power conversion device includes a power converter connected to an electrical storage device that stores DC power, and having a function to convert the DC power stored in the electrical storage device into AC power, and also having a function to output the AC power to one or both of a customer load and a power system; a detection unit that detects voltage and current at a first point on a power line that connects the power converter with the power system; and a control unit that generates a drive command for controlling the power converter based on the voltage and the current detected by the detection unit. The customer load is connected to a second point, on the power line, between the power converter and the first point. The power converter operates on the basis of the drive command generated by the control unit.
    Type: Grant
    Filed: December 14, 2017
    Date of Patent: February 16, 2021
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kikuo Izumi, Takahiro Kato, Yutaka Kuboyama
  • Publication number: 20210013796
    Abstract: A power conversion device converts a direct-current power on the DC side of the power conversion device to an alternating-current power by an inverter circuit having a plurality of semiconductor switching elements, and outputs the AC power from the AC side of the power conversion device. A current detector detects a reactor current output from the inverter circuit. As overcurrent detector detects overcurrent in a control mode in which the reactor current is caused to follow a reactor current command value, control circuit starts an overcurrent mode in which a time period where the reactor current monotonically decreases is provided. In the overcurrent mode, whether to switch the overcurrent mode to the normal control mode is determined based on the reactor current or in accordance with a timing corresponding to a zero-cross point of a voltage or current on the AC side.
    Type: Application
    Filed: January 9, 2019
    Publication date: January 14, 2021
    Applicant: Mitsubishi Electric Corporation
    Inventors: Takeshi AMIMOTO, Kikuo IZUMI, Tatsuya OKUDA, Tomoaki KIMURA
  • Publication number: 20200395782
    Abstract: A power conversion device includes: a power converter connected to an electrical storage device that stores direct current power, the power converter being capable of converting the direct current power stored in the electrical storage device to alternating current power and outputting the alternating current power to a power system and to a customer load; and a control unit to control the power converter on a basis of a first active power command value and a first reactive power command value provided from an external controller, of a power consumption of the customer load, of a current root-mean-square value of a power flow current supplied to the power system, and a current upper limit that is set on a basis of a rated current of a molded case circuit breaker connected between the power converter and the power system.
    Type: Application
    Filed: March 23, 2018
    Publication date: December 17, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Yutaka KUBOYAMA, Kikuo IZUMI, Takahiro KATO
  • Publication number: 20200389100
    Abstract: A power conversion device includes a power converter connected to an electrical storage device that stores DC power, and having a function to convert the DC power stored in the electrical storage device into AC power, and also having a function to output the AC power to one or both of a customer load and a power system; a detection unit that detects voltage and current at a first point on a power line that connects the power converter with the power system; and a control unit that generates a drive command for controlling the power converter based on the voltage and the current detected by the detection unit. The customer load is connected to a second point, on the power line, between the power converter and the first point. The power converter operates on the basis of the drive command generated by the control unit.
    Type: Application
    Filed: December 14, 2017
    Publication date: December 10, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kikuo IZUMI, Takahiro KATO, Yutaka KUBOYAMA
  • Patent number: 10855084
    Abstract: A power system and a power conversion device are interconnected via an interconnection switch. A user load is provided between the power conversion device and the interconnection switch. In parallel with the interconnection switch, a series circuit composed of a load disconnection switch and a voltage maintenance load for maintaining voltage of the user load at the time of system momentary power interruption is connected. Control is performed such that, when momentary power interruption occurs, the interconnection switch is turned off and the power system and the power conversion device are connected via the voltage maintenance load, and at the time of recovery from the momentary power interruption, the interconnection switch is turned on, further the power system and the power conversion device are connected.
    Type: Grant
    Filed: May 12, 2017
    Date of Patent: December 1, 2020
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kikuo Izumi, Tatsuya Okuda, Masahiro Sugahara
  • Publication number: 20200244096
    Abstract: The power conversion device includes common DC buses, AC buses, DC connection terminals, AC connection terminals, N pairs of distributed power supply connection terminals, N DC/DC converters for transferring power between the common DC buses and the distributed power supply connection terminals, M DC/AC converters for transferring power between the AC buses and the common DC buses, and a control unit for controlling each converter on the basis of a high-order control command. The DC connection terminals are connected to the common DC buses and connected to an external DC power distribution grid, the AC connection terminals are connected to the AC buses and connected to an external AC power distribution grid, and the distributed power supply connection terminals are connected to the DC/DC converters and connected to external DC distributed power supplies.
    Type: Application
    Filed: April 16, 2020
    Publication date: July 30, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Akiko TABUCHI, Kikuo IZUMI, Naohisa KAWAHARA, Daigo TAKEMURA
  • Publication number: 20200204057
    Abstract: A controller of each power conversion device in a power conversion system controls a switching element unit, based on a detected value of reactor current flowing through a filter reactor, a detected value of output voltage output between the terminals of a filter capacitor, and a detected value of output current flowing through an output reactor. The controller generates a voltage command based on the output current and the output voltage and generates a correction amount of the voltage command based on the output current in which a reference frequency component is removed. The controller generates a current command based on the addition value of the voltage command and the correction amount and controls the switching element unit such that the reactor current matches the current command.
    Type: Application
    Filed: February 19, 2018
    Publication date: June 25, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Takahiro KATO, Kikuo IZUMI, Akiko TABUCHI
  • Publication number: 20200059103
    Abstract: A power system and a power conversion device are interconnected via an interconnection switch. A user load is provided between the power conversion device and the interconnection switch. In parallel with the interconnection switch, a series circuit composed of a load disconnection switch and a voltage maintenance load for maintaining voltage of the user load at the time of system momentary power interruption is connected. Control is performed such that, when momentary power interruption occurs, the interconnection switch is turned off and the power system and the power conversion device are connected via the voltage maintenance load, and at the time of recovery from the momentary power interruption, the interconnection switch is turned on, further the power system and the power conversion device are connected.
    Type: Application
    Filed: May 12, 2017
    Publication date: February 20, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kikuo IZUMI, Tatsuya OKUDA, Masahiro SUGAHARA
  • Patent number: 10320310
    Abstract: A power conversion device includes: a power conversion unit composed of a power conversion circuit having switching elements, an output current measurement unit, an output voltage measurement unit, and reactor; a voltage command generating unit for generating a voltage command; a dead time correction unit for calculating a dead time correction amount for correcting voltage error, between the voltage command and output voltage, caused due to dead time; and a PWM signal generating unit for generating switching signals according to the voltage command and the dead time correction amount, wherein the dead time correction unit calculates the dead time correction amount from the voltage command, the measured output voltage, and the measured output current.
    Type: Grant
    Filed: June 24, 2014
    Date of Patent: June 11, 2019
    Assignee: Mitsubishi Electric Corporation
    Inventors: Takahiro Kato, Kikuo Izumi
  • Patent number: 10256713
    Abstract: A power conversion device which converts power between a power grid and a DC power supply, includes: AC/DC converters for performing conversion from AC power to DC power or from DC power to AC power between the power grid and the DC power supply; a capacitor provided on the DC power supply side of the AC/DC converters and storing DC power; and a step-up unit for charging the capacitor.
    Type: Grant
    Filed: May 30, 2016
    Date of Patent: April 9, 2019
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Tomohito Fukuda, Hitoshi Kawaguchi, Kikuo Izumi, Masanori Kageyama
  • Patent number: 10256747
    Abstract: In a control unit for drive-controlling a switching element unit of each power conversion device, a voltage correction amount calculation unit calculates a correction amount corresponding to voltage drop due to impedance between the switching element unit and filter reactor. A voltage command correcting unit corrects a voltage command generated by the voltage command generation unit, using the correction amount. Thus, for a power conversion device 21 that has a small output impedance, correction is performed so as to increase the output impedance, and a PLL unit changes the frequency in accordance with active power calculated from output voltage and output current of the power conversion device, so as to uniform power allocations.
    Type: Grant
    Filed: November 16, 2016
    Date of Patent: April 9, 2019
    Assignee: Mitsubishi Electric Corporation
    Inventors: Takahiro Kato, Yu Kawai, Kenji Fujiwara, Kikuo Izumi, Tatsuya Okuda
  • Publication number: 20180358907
    Abstract: In a control unit for drive-controlling a switching element unit of each power conversion device, a voltage correction amount calculation unit calculates a correction amount corresponding to voltage drop due to impedance between the switching element unit and filter reactor. A voltage command correcting unit corrects a voltage command generated by the voltage command generation unit, using the correction amount. Thus, for a power conversion device 21 that has a small output impedance, correction is performed so as to increase the output impedance, and a PLL unit changes the frequency in accordance with active power calculated from output voltage and output current of the power conversion device, so as to uniform power allocations.
    Type: Application
    Filed: November 16, 2016
    Publication date: December 13, 2018
    Applicant: Mitsubishi Electric Corporation
    Inventors: Takahiro KATO, Yu KAWAI, Kenji FUJIWARA, Kikuo IZUMI, Tatsuya OKUDA
  • Patent number: 10084315
    Abstract: A power conversion circuit for converting DC power supplied from a DC power supply to AC power; and a power conversion control section for controlling operation of the power conversion circuit so as to generate autonomous operation power as an AC voltage source in a parallel-off state from a power grid. The power conversion control section includes: an AC voltage control section for controlling AC voltage; an AC current suppression section for limiting AC current to a predetermined current limit value or smaller; and a DC voltage shortage suppression section for, when DC voltage of the power conversion circuit reduces, in response thereto, reducing the current limit value to be given to the AC current suppression section.
    Type: Grant
    Filed: July 4, 2014
    Date of Patent: September 25, 2018
    Assignee: Mitsubishi Electric Corporation
    Inventors: Tatsuya Okuda, Kikuo Izumi, Takahiro Kato
  • Publication number: 20180083527
    Abstract: A power conversion device which converts power between a power grid and a DC power supply, includes: AC/DC converters for performing conversion from AC power to DC power or from DC power to AC power between the power grid and the DC power supply; a capacitor provided on the DC power supply side of the AC/DC converters and storing DC power; and a step-up unit for charging the capacitor.
    Type: Application
    Filed: May 30, 2016
    Publication date: March 22, 2018
    Applicant: Mitsubishi Electric Corporation
    Inventors: Tomohito FUKUDA, Hitoshi KAWAGUCHI, Kikuo IZUMI, Masanori KAGEYAMA
  • Patent number: 9912150
    Abstract: In a power control system which connects power from the power storage device to a power grid and supplies power to a load, the power from the power storage device is connected to the load and the power grid via a DC/DC converter, a smoothing capacitor, and a DC/AC converter. By a first power control unit for controlling flow power of the power grid to be a power command value, and by a second power control unit for suppressing reverse flow power, an output power command for the DC/AC converter is generated, an output power command for the DC/DC converter is generated so that voltage of the smoothing capacitor becomes target voltage, and the output power command is corrected so as to suppress voltage variation in the smoothing capacitor.
    Type: Grant
    Filed: May 21, 2014
    Date of Patent: March 6, 2018
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kikuo Izumi, Tatsuya Okuda, Tsutomu Shimazaki, Naohide Tsuchimoto
  • Publication number: 20170117821
    Abstract: A power conversion device includes: a power conversion unit composed of a power conversion circuit having switching elements, an output current measurement unit, an output voltage measurement unit, and reactor; a voltage command generating unit for generating a voltage command; a dead time correction unit for calculating a dead time correction amount for correcting voltage error, between the voltage command and output voltage, caused due to dead time; and a PWM signal generating unit for generating switching signals according to the voltage command and the dead time correction amount, wherein the dead time correction unit calculates the dead time correction amount from the voltage command, the measured output voltage, and the measured output current.
    Type: Application
    Filed: June 24, 2014
    Publication date: April 27, 2017
    Applicant: Mitsubishi Electric Corporation
    Inventors: Takahiro KATO, Kikuo IZUMI
  • Publication number: 20160204691
    Abstract: A power conversion circuit for converting DC power supplied from a DC power supply to AC power; and a power conversion control section for controlling operation of the power conversion circuit so as to generate autonomous operation power as an AC voltage source in a parallel-off state from a power grid. The power conversion control section includes: an AC voltage control section for controlling AC voltage; an AC current suppression section for limiting AC current to a predetermined current limit value or smaller; and a DC voltage shortage suppression section for, when DC voltage of the power conversion circuit reduces, in response thereto, reducing the current limit value to be given to the AC current suppression section.
    Type: Application
    Filed: July 4, 2014
    Publication date: July 14, 2016
    Applicant: Mitsubishi Electric Corporation
    Inventors: Tatsuya OKUDA, Kikuo IZUMI, Takahiro KATO
  • Publication number: 20160072281
    Abstract: In a power control system which connects power from the power storage device to a power grid and supplies power to a load, the power from the power storage device is connected to the load and the power grid via a DC/DC converter, a smoothing capacitor, and a DC/AC converter. By a first power control unit for controlling flow power of the power grid to be a power command value, and by a second power control unit for suppressing reverse flow power, an output power command for the DC/AC converter is generated, an output power command for the DC/DC converter is generated so that voltage of the smoothing capacitor becomes target voltage, and the output power command is corrected so as to suppress voltage variation in the smoothing capacitor.
    Type: Application
    Filed: May 21, 2014
    Publication date: March 10, 2016
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kikuo IZUMI, Tatsuya OKUDA, Tsutomu SHIMAZAKI, Naohide TSUCHIMOTO