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).
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Patent number: 10924024Abstract: 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: GrantFiled: August 28, 2017Date of Patent: February 16, 2021Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO, LTD.Inventors: Takaaki Norisada, Keiji Akamatsu, Fumito Kusama, Go Yamada, Yutaka Kamon, Makoto Ozone
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Publication number: 20190207527Abstract: 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: ApplicationFiled: August 28, 2017Publication date: July 4, 2019Inventors: Takaaki NORISADA, Keiji AKAMATSU, Fumito KUSAMA, Go YAMADA, Yutaka KAMON, Makoto OZONE
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Patent number: 9866135Abstract: 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: GrantFiled: March 21, 2017Date of Patent: January 9, 2018Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.Inventors: Fumito Kusama, Takaaki Norisada, Go Yamada, Keiji Akamatsu
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Power conversion device including primary inverter, transformer, secondary converter, and controller
Patent number: 9866129Abstract: 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: GrantFiled: March 14, 2017Date of Patent: January 9, 2018Assignee: Panasonic Intellectual Property Management Co., Ltd.Inventors: Takaaki Norisada, Fumito Kusama, Go Yamada, Keiji Akamatsu -
POWER CONVERSION DEVICE INCLUDING PRIMARY INVERTER, TRANSFORMER, SECONDARY CONVERTER, AND CONTROLLER
Publication number: 20170294843Abstract: 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: ApplicationFiled: March 14, 2017Publication date: October 12, 2017Inventors: TAKAAKI NORISADA, FUMITO KUSAMA, GO YAMADA, KEIJI AKAMATSU -
Publication number: 20170294845Abstract: 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: ApplicationFiled: March 21, 2017Publication date: October 12, 2017Inventors: FUMITO KUSAMA, TAKAAKI NORISADA, GO YAMADA, KEIJI AKAMATSU
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Patent number: 9667159Abstract: 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: GrantFiled: July 28, 2015Date of Patent: May 30, 2017Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.Inventors: Keiji Akamatsu, Takaaki Norisada, Sohei Okamoto, Daisuke Fukuda, Goh Yamada
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Patent number: 9548676Abstract: 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: GrantFiled: October 19, 2015Date of Patent: January 17, 2017Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.Inventors: Daisuke Fukuda, Keiji Akamatsu, Takaaki Norisada
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Patent number: 9543858Abstract: 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: GrantFiled: July 4, 2014Date of Patent: January 10, 2017Assignee: Panasonic Intellectual Property Management Co., Ltd.Inventors: Osamu Kusumoto, Hideki Nakata, Keiji Akamatsu, Masao Uchida
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Patent number: 9543823Abstract: 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: GrantFiled: October 20, 2015Date of Patent: January 10, 2017Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.Inventors: Goh Yamada, Sohei Okamoto, Keiji Akamatsu, Daisuke Fukuda, Takaaki Norisada
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Patent number: 9487098Abstract: 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: GrantFiled: February 20, 2015Date of Patent: November 8, 2016Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.Inventors: Goh Yamada, Takaaki Norisada, Hajime Hida, Sohei Okamoto, Keiji Akamatsu
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Patent number: 9431917Abstract: 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: GrantFiled: January 8, 2015Date of Patent: August 30, 2016Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.Inventors: Sohei Okamoto, Goh Yamada, Daisuke Fukuda, Takaaki Norisada, Keiji Akamatsu
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Publication number: 20160141972Abstract: 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: ApplicationFiled: October 20, 2015Publication date: May 19, 2016Inventors: GOH YAMADA, SOHEI OKAMOTO, KEIJI AKAMATSU, DAISUKE FUKUDA, TAKAAKI NORISADA
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Publication number: 20160141970Abstract: 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: ApplicationFiled: October 19, 2015Publication date: May 19, 2016Inventors: DAISUKE FUKUDA, KEIJI AKAMATSU, TAKAAKI NORISADA
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Publication number: 20160105119Abstract: 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: ApplicationFiled: July 28, 2015Publication date: April 14, 2016Inventors: KEIJI AKAMATSU, TAKAAKI NORISADA, SOHEI OKAMOTO, DAISUKE FUKUDA, GOH YAMADA
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Patent number: 9287790Abstract: 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: GrantFiled: December 10, 2014Date of Patent: March 15, 2016Assignee: Panasonic Intellectual Property Management Co., Ltd.Inventors: Takaaki Norisada, Keiji Akamatsu
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Publication number: 20150280611Abstract: 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: ApplicationFiled: July 4, 2014Publication date: October 1, 2015Inventors: Osamu Kusumoto, Hideki Nakata, Keiji Akamatsu, Masao Uchida
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Publication number: 20150256089Abstract: 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: ApplicationFiled: February 20, 2015Publication date: September 10, 2015Inventors: GOH YAMADA, TAKAAKI NORISADA, HAJIME HIDA, SOHEI OKAMOTO, KEIJI AKAMATSU
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Publication number: 20150207424Abstract: 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: ApplicationFiled: January 8, 2015Publication date: July 23, 2015Inventors: SOHEI OKAMOTO, GOH YAMADA, DAISUKE FUKUDA, TAKAAKI NORISADA, KEIJI AKAMATSU
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Publication number: 20150180356Abstract: 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: ApplicationFiled: December 10, 2014Publication date: June 25, 2015Inventors: TAKAAKI NORISADA, KEIJI AKAMATSU