Patents by Inventor Keiji Akamatsu

Keiji Akamatsu 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: 10924024
    Abstract: A control unit controls an inverter circuit such that a positive voltage and a negative voltage are alternately applied to a primary winding. The control unit controls a cycloconverter so as to allow no power to be transmitted between the cycloconverter and the inverter circuit in a first period including an inversion period during which a voltage of the primary winding has its polarity inverted. The control unit also controls the cycloconverter so as to allow power to be transmitted either in a first direction from the cycloconverter toward the inverter circuit, or in a second direction opposite from the first direction, in a second period different from the first period.
    Type: Grant
    Filed: August 28, 2017
    Date of Patent: February 16, 2021
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO, LTD.
    Inventors: Takaaki Norisada, Keiji Akamatsu, Fumito Kusama, Go Yamada, Yutaka Kamon, Makoto Ozone
  • Publication number: 20190207527
    Abstract: A control unit controls an inverter circuit such that a positive voltage and a negative voltage are alternately applied to a primary winding. The control unit controls a cycloconverter so as to allow no power to be transmitted between the cycloconverter and the inverter circuit in a first period including an inversion period during which a voltage of the primary winding has its polarity inverted. The control unit also controls the cycloconverter so as to allow power to be transmitted either in a first direction from the cycloconverter toward the inverter circuit, or in a second direction opposite from the first direction, in a second period different from the first period.
    Type: Application
    Filed: August 28, 2017
    Publication date: July 4, 2019
    Inventors: Takaaki NORISADA, Keiji AKAMATSU, Fumito KUSAMA, Go YAMADA, Yutaka KAMON, Makoto OZONE
  • Patent number: 9866129
    Abstract: A power converter includes first to fourth terminals, a transformer including primary and secondary windings, an inverter connected between the first and second terminals and the primary winding, a converter connected between fifth and sixth terminals, and a controller. The converter includes first to eighth switch circuits each including a diode and a switch connected in parallel. When a voltage between the fifth and sixth terminals has first polarity, the controller controls the first switch circuit to be in on-state during a first on-period and controls the fifth switch circuit to be in on-state during a second on-period completely including the first on-period. When the voltage between the fifth and sixth terminals has second polarity, the controller controls the second switch circuit to be in on-state during a third on-period and controls the sixth switch circuit to be in on-state during a fourth on-period completely including the third on-period.
    Type: Grant
    Filed: March 14, 2017
    Date of Patent: January 9, 2018
    Assignee: Panasonic Intellectual Property Management Co., Ltd.
    Inventors: Takaaki Norisada, Fumito Kusama, Go Yamada, Keiji Akamatsu
  • Patent number: 9866135
    Abstract: A power conversion device includes first and second terminals connected to a DC power source, third and fourth terminals connected to a commercial power system or a load, a transformer including a primary winding having seventh and eighth terminals and a secondary winding having fifth and sixth terminals, an inverter circuit connected between the first and second terminals and the seventh and eighth terminals, a converter circuit connected between the fifth and sixth terminals and the third and fourth terminals, a diode bridge including first and second AC input terminals connected to the fifth and sixth terminals, respectively, and first and second DC output terminals, a first capacitor connected between the first and second DC output terminals, and a first resistor connected in parallel with the first capacitor between the first and second DC output terminals.
    Type: Grant
    Filed: March 21, 2017
    Date of Patent: January 9, 2018
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
    Inventors: Fumito Kusama, Takaaki Norisada, Go Yamada, Keiji Akamatsu
  • Publication number: 20170294845
    Abstract: A power conversion device includes first and second terminals connected to a DC power source, third and fourth terminals connected to a commercial power system or a load, a transformer including a primary winding having seventh and eighth terminals and a secondary winding having fifth and sixth terminals, an inverter circuit connected between the first and second terminals and the seventh and eighth terminals, a converter circuit connected between the fifth and sixth terminals and the third and fourth terminals, a diode bridge including first and second AC input terminals connected to the fifth and sixth terminals, respectively, and first and second DC output terminals, a first capacitor connected between the first and second DC output terminals, and a first resistor connected in parallel with the first capacitor between the first and second DC output terminals.
    Type: Application
    Filed: March 21, 2017
    Publication date: October 12, 2017
    Inventors: FUMITO KUSAMA, TAKAAKI NORISADA, GO YAMADA, KEIJI AKAMATSU
  • Publication number: 20170294843
    Abstract: A power converter includes first to fourth terminals, a transformer including primary and secondary windings, an inverter connected between the first and second terminals and the primary winding, a converter connected between fifth and sixth terminals, and a controller. The converter includes first to eighth switch circuits each including a diode and a switch connected in parallel. When a voltage between the fifth and sixth terminals has first polarity, the controller controls the first switch circuit to be in on-state during a first on-period and controls the fifth switch circuit to be in on-state during a second on-period completely including the first on-period. When the voltage between the fifth and sixth terminals has second polarity, the controller controls the second switch circuit to be in on-state during a third on-period and controls the sixth switch circuit to be in on-state during a fourth on-period completely including the third on-period.
    Type: Application
    Filed: March 14, 2017
    Publication date: October 12, 2017
    Inventors: TAKAAKI NORISADA, FUMITO KUSAMA, GO YAMADA, KEIJI AKAMATSU
  • Patent number: 9667159
    Abstract: A control unit controls the amplitude of at least either an output voltage or an output current by shifting at least either a first on time or a second on time.
    Type: Grant
    Filed: July 28, 2015
    Date of Patent: May 30, 2017
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
    Inventors: Keiji Akamatsu, Takaaki Norisada, Sohei Okamoto, Daisuke Fukuda, Goh Yamada
  • Patent number: 9548676
    Abstract: A power conversion apparatus that switches, with a relay unit, from a disconnected state to a connected state between a connector and at least one of a commercial power system and a load while a switching device is in an off state.
    Type: Grant
    Filed: October 19, 2015
    Date of Patent: January 17, 2017
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
    Inventors: Daisuke Fukuda, Keiji Akamatsu, Takaaki Norisada
  • Patent number: 9543858
    Abstract: A semiconductor device includes a gate pad, a first source pad and a second source pad insulated from each other, a drain pad, a main region, and a sense region for detecting a forward current and a reverse current. The main region and the sense region each include a plurality of unit cells which are in parallel connection, the number of unit cells in the sense region being smaller than the number of unit cells in the main region. A source electrode of any unit cell in the main region is connected to the first source pad, and a source electrode of any unit cell in the sense region is connected to the second source pad.
    Type: Grant
    Filed: July 4, 2014
    Date of Patent: January 10, 2017
    Assignee: Panasonic Intellectual Property Management Co., Ltd.
    Inventors: Osamu Kusumoto, Hideki Nakata, Keiji Akamatsu, Masao Uchida
  • Patent number: 9543823
    Abstract: A power conversion apparatus includes an inductor inserted between a secondary winding and a switching device, and an auxiliary switching device inserted between the secondary winding and the switching device in parallel to the inductor. The auxiliary switching device is in an off state in a power supply mode in which an output voltage and an output current of a connector have the same polarity. The auxiliary switching device is in an on state in a power regeneration mode in which the output voltage and the output current of the connector have different polarities.
    Type: Grant
    Filed: October 20, 2015
    Date of Patent: January 10, 2017
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
    Inventors: Goh Yamada, Sohei Okamoto, Keiji Akamatsu, Daisuke Fukuda, Takaaki Norisada
  • Patent number: 9487098
    Abstract: A power conversion apparatus according to one aspect of the present disclosure comprises a bridge circuit including a first switch and a second switch, a first auxiliary switch, a first auxiliary inductor, a control device, a transformer, a secondary-side inductor, a rectifier circuit, a smoothing circuit, and an output detection circuit. The control device performs an on/off operation on the first auxiliary switch if a value detected by the output detection circuit is smaller than or equal to a setting value, and maintains the first auxiliary switch in an off state if the detected value exceeds the setting value.
    Type: Grant
    Filed: February 20, 2015
    Date of Patent: November 8, 2016
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
    Inventors: Goh Yamada, Takaaki Norisada, Hajime Hida, Sohei Okamoto, Keiji Akamatsu
  • Patent number: 9431917
    Abstract: An electric power converter includes a bridge circuit, a transformer, a rectifier circuit, and a smoothing circuit. The rectifier circuit includes a first secondary-side diode disposed in a first current path extending between one end of a secondary winding and a first terminal of the smoothing circuit, a second secondary-side diode disposed in a second current path extending between the other end of the secondary winding and the first terminal of the smoothing circuit, a third secondary-side diode, a fourth secondary-side diode, a first secondary-side switching element, and a second secondary-side switching element. The first secondary-side switching element and the second secondary-side switching element are connected in common to a first node at which the first current path and the second current path are connected to each other.
    Type: Grant
    Filed: January 8, 2015
    Date of Patent: August 30, 2016
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
    Inventors: Sohei Okamoto, Goh Yamada, Daisuke Fukuda, Takaaki Norisada, Keiji Akamatsu
  • Publication number: 20160141972
    Abstract: A power conversion apparatus includes an inductor inserted between a secondary winding and a switching device, and an auxiliary switching device inserted between the secondary winding and the switching device in parallel to the inductor. The auxiliary switching device is in an off state in a power supply mode in which an output voltage and an output current of a connector have the same polarity. The auxiliary switching device is in an on state in a power regeneration mode in which the output voltage and the output current of the connector have different polarities.
    Type: Application
    Filed: October 20, 2015
    Publication date: May 19, 2016
    Inventors: GOH YAMADA, SOHEI OKAMOTO, KEIJI AKAMATSU, DAISUKE FUKUDA, TAKAAKI NORISADA
  • Publication number: 20160141970
    Abstract: A power conversion apparatus that switches, with a relay unit, from a disconnected state to a connected state between a connector and at least one of a commercial power system and a load while a switching device is in an off state.
    Type: Application
    Filed: October 19, 2015
    Publication date: May 19, 2016
    Inventors: DAISUKE FUKUDA, KEIJI AKAMATSU, TAKAAKI NORISADA
  • Publication number: 20160105119
    Abstract: A control unit controls the amplitude of at least either an output voltage or an output current by shifting at least either a first on time or a second on time.
    Type: Application
    Filed: July 28, 2015
    Publication date: April 14, 2016
    Inventors: KEIJI AKAMATSU, TAKAAKI NORISADA, SOHEI OKAMOTO, DAISUKE FUKUDA, GOH YAMADA
  • Patent number: 9287790
    Abstract: An electric power converter includes a capacitor, a bridge circuit that includes a plurality of switching elements, a transformer, a secondary side rectifier circuit, a smoothing circuit, a detector that detects a value based on at least one of a capacitor voltage and a current flowing from the capacitor, and a control device that outputs a primary side drive signal to turns on/off each of the plurality of switching elements at a switching frequency, the control device increasing the switching frequency when the detected value increases, the control device reducing the switching frequency when the detected value decreases.
    Type: Grant
    Filed: December 10, 2014
    Date of Patent: March 15, 2016
    Assignee: Panasonic Intellectual Property Management Co., Ltd.
    Inventors: Takaaki Norisada, Keiji Akamatsu
  • Publication number: 20150280611
    Abstract: A semiconductor device includes a gate pad, a first source pad and a second source pad insulated from each other, a drain pad, a main region, and a sense region for detecting a forward current and a reverse current. The main region and the sense region each include a plurality of unit cells which are in parallel connection, the number of unit cells in the sense region being smaller than the number of unit cells in the main region. A source electrode of any unit cell in the main region is connected to the first source pad, and a source electrode of any unit cell in the sense region is connected to the second source pad.
    Type: Application
    Filed: July 4, 2014
    Publication date: October 1, 2015
    Inventors: Osamu Kusumoto, Hideki Nakata, Keiji Akamatsu, Masao Uchida
  • Publication number: 20150256089
    Abstract: A power conversion apparatus according to one aspect of the present disclosure comprises a bridge circuit including a first switch and a second switch, a first auxiliary switch, a first auxiliary inductor, a control device, a transformer, a secondary-side inductor, a rectifier circuit, a smoothing circuit, and an output detection circuit. The control device performs an on/off operation on the first auxiliary switch if a value detected by the output detection circuit is smaller than or equal to a setting value, and maintains the first auxiliary switch in an off state if the detected value exceeds the setting value.
    Type: Application
    Filed: February 20, 2015
    Publication date: September 10, 2015
    Inventors: GOH YAMADA, TAKAAKI NORISADA, HAJIME HIDA, SOHEI OKAMOTO, KEIJI AKAMATSU
  • Publication number: 20150207424
    Abstract: An electric power converter includes a bridge circuit, a transformer, a rectifier circuit, and a smoothing circuit. The rectifier circuit includes a first secondary-side diode disposed in a first current path extending between one end of a secondary winding and a first terminal of the smoothing circuit, a second secondary-side diode disposed in a second current path extending between the other end of the secondary winding and the first terminal of the smoothing circuit, a third secondary-side diode, a fourth secondary-side diode, a first secondary-side switching element, and a second secondary-side switching element. The first secondary-side switching element and the second secondary-side switching element are connected in common to a first node at which the first current path and the second current path are connected to each other.
    Type: Application
    Filed: January 8, 2015
    Publication date: July 23, 2015
    Inventors: SOHEI OKAMOTO, GOH YAMADA, DAISUKE FUKUDA, TAKAAKI NORISADA, KEIJI AKAMATSU
  • Publication number: 20150180356
    Abstract: An electric power converter includes a capacitor, a bridge circuit that includes a plurality of switching elements, a transformer, a secondary side rectifier circuit, a smoothing circuit, a detector that detects a value based on at least one of a capacitor voltage and a current flowing from the capacitor, and a control device that outputs a primary side drive signal to turns on/off each of the plurality of switching elements at a switching frequency, the control device increasing the switching frequency when the detected value increases, the control device reducing the switching frequency when the detected value decreases.
    Type: Application
    Filed: December 10, 2014
    Publication date: June 25, 2015
    Inventors: TAKAAKI NORISADA, KEIJI AKAMATSU