Patents by Inventor Kotaro Higashi
Kotaro Higashi 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: 9812992Abstract: In a power conversion system in which one or more converter cells are connected in series to form an arm for each phase, a control device includes a voltage command generating unit for generating a positive arm voltage command and a negative arm voltage command for each phase. The voltage command generating unit includes an AC current control unit, a circulating current control unit, and a command distributing unit. On the basis of inputted voltage commands, the command distributing unit subtracts voltage drop portions due to inductance values in the arms from respective voltages assigned as outputs of the positive arm and the negative arm, to distribute voltage components, thereby determining the positive arm voltage command and the negative arm voltage command.Type: GrantFiled: December 3, 2014Date of Patent: November 7, 2017Assignees: Mitsubishi Electric Corporation, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Kaho Mukunoki, Toshiyuki Fujii, Osamu Mori, Shinzo Tamai, Sadao Funahashi, Yasuhiko Hosokawa, Kotaro Higashi
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Patent number: 9806630Abstract: A power conversion device performs power conversion between three-phase AC, and DC, and includes a positive arm and a negative arm for each phase, each of which includes one or more converter cells connected in series. A voltage command generating unit in a control device includes an AC current control unit, a circulating current control unit, and a command distributing unit, and generates a positive arm voltage command and a negative arm voltage command for each phase. In the circulating current control unit, a compensator calculates a first control command so that circulating current for each phase approaches a circulating current command value, a suppression unit generates a second control command so as to suppress a 2f component and a 4f component contained in the first control command, and then the first control command and the second control command are combined to generate a circulation control command.Type: GrantFiled: July 23, 2015Date of Patent: October 31, 2017Assignees: Mitsubishi Electric Corporation, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Kaho Mukunoki, Toshiyuki Fujii, Miwako Tanaka, Osamu Mori, Shinzo Tamai, Sadao Funahashi, Yasuhiko Hosokawa, Kotaro Higashi
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Patent number: 9780685Abstract: An electrical power converter includes: AC voltage terminals U, V, and W; DC voltage terminals P and N; a converter cell series unit composed of one or more converter cells connected in series between the AC voltage terminals U, V, and W and the DC voltage terminals P and N, each converter cell including a semiconductor element and a capacitor; and a first inductance connected in series to the converter cell series unit, between, of the DC voltage terminals P and N, a DC voltage terminal at the lowest potential with respect to the ground, and the AC voltage terminals U, V, and W.Type: GrantFiled: July 2, 2013Date of Patent: October 3, 2017Assignees: Mitsubishi Electric Corporation, Toshiba Mitsubishi-Electric Industrial Systems CorporationInventors: Takushi Jimichi, Kimiyuki Koyanagi, Satoshi Azuma, Sadao Funahashi, Shinzo Tamai, Yasuhiko Hosokawa, Kotaro Higashi
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Patent number: 9755542Abstract: In a power converter which performs power conversion between plural-phase AC and DC, variation in voltage of the DC capacitor in each converter cell is detected, and when the variation exceeds a predetermined value, a DC voltage command value as a control target value in a DC voltage control unit which controls DC voltage between DC buses is corrected by being increased or decreased. Thus, when AC grid failure occurs, the capacitor voltage of each converter cell is maintained and the operation continuity is improved.Type: GrantFiled: May 19, 2015Date of Patent: September 5, 2017Assignees: Mitsubishi Electric Corporation, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Toshiyuki Fujii, Kaho Mukunoki, Osamu Mori, Shinzo Tamai, Sadao Funahashi, Yasuhiko Hosokawa, Kotaro Higashi
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Publication number: 20170214334Abstract: A power conversion device performs power conversion between three-phase AC, and DC, and includes a positive arm and a negative arm for each phase, each of which includes one or more converter cells connected in series. A voltage command generating unit in a control device includes an AC current control unit, a circulating current control unit, and a command distributing unit, and generates a positive arm voltage command and a negative arm voltage command for each phase. In the circulating current control unit, a compensator calculates a first control command so that circulating current for each phase approaches a circulating current command value, a suppression unit generates a second control command so as to suppress a 2f component and a 4f component contained in the first control command, and then the first control command and the second control command are combined to generate a circulation control command.Type: ApplicationFiled: July 23, 2015Publication date: July 27, 2017Applicants: Mitsubishi Electric Corporation, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Kaho MUKUNOKI, Toshiyuki FUJII, Miwako TANAKA, Osamu MORI, Shinzo TAMAI, Sadao FUNAHASHI, Yasuhiko HOSOKAWA, Kotaro HIGASHI
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Patent number: 9712084Abstract: An electric power conversion device includes a power conversion unit and a converter control unit. The power conversion unit includes three arms connected to an AC circuit. The converter control unit includes a phase DC voltage control unit, a negative sequence current command value calculation unit, an output current control unit, a circulating current control unit, a voltage command value calculation unit, and a gate signal generation unit, and imbalance of cell DC capacitor voltages among phases due to grid imbalance is controlled by circulating current and negative sequence current.Type: GrantFiled: July 2, 2014Date of Patent: July 18, 2017Assignees: Mitsubishi Electric Corporation, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Takeshi Kikuchi, Kaho Mukunoki, Toshiyuki Fujii, Osamu Mori, Shinzo Tamai, Sadao Funahashi, Yasuhiko Hosokawa, Kotaro Higashi
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Publication number: 20170047860Abstract: In a power converter which performs power conversion between plural-phase AC and DC, variation in voltage of the DC capacitor in each converter cell is detected, and when the variation exceeds a predetermined value, a DC voltage command value as a control target value in a DC voltage control unit which controls DC voltage between DC buses is corrected by being increased or decreased. Thus, when AC grid failure occurs, the capacitor voltage of each converter cell is maintained and the operation continuity is improved.Type: ApplicationFiled: May 19, 2015Publication date: February 16, 2017Applicants: MITSUBISHI ELECTRIC CORPORATION, TOSHIBA MITSUBISHI- ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Toshiyuki FUJII, Kaho MUKUNOKI, Osamu MORI, Shinzo TAMAI, Sadao FUNAHASHI, Yasuhiko HOSOKAWA, Kotaro HIGASHI
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Patent number: 9564827Abstract: A power conversion device includes: a DC current calculation unit for calculating a circulating current component for each phase which circulates between the phases through first arms and/or second arms not via an AC power supply and a DC power supply; and a circulating current control unit for controlling the circulating current component for each phase so as to follow a predetermined circulating current command value, thereby reliably suppressing variation in voltages of DC capacitors of unit cells among the phases even in such a case where an impedance is additionally inserted in a DC circuit.Type: GrantFiled: September 4, 2013Date of Patent: February 7, 2017Assignees: Mitsubishi Electric Corporation, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Kaho Mukunoki, Toshiyuki Fujii, Osamu Mori, Shinzo Tamai, Sadao Funahashi, Yasuhiko Hosokawa, Kotaro Higashi
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Patent number: 9564808Abstract: An electric power conversion device includes a plurality of cell converters connected in cascade and including main circuits, drive circuits, and self-feeding devices for supplying power to the drive circuits by being supplied with power from the main circuits. The drive circuit is supplied with power via a first feed line from the self-feeding device in the corresponding cell converter, and supplied with power from the self-feeding device in another cell converter via a second feed line on which an insulation input/output circuit is provided. When the self-feeding device is abnormal, the drive circuit is supplied with power from the self-feeding device in the other cell converter, whereby the electric power conversion device continuously provides a desired output.Type: GrantFiled: September 2, 2013Date of Patent: February 7, 2017Assignees: Mitsubishi Electric Corporation, Toshiba Mitsubishi-Electric Industrial Systems CorporationInventors: Kimiyuki Koyanagi, Takushi Jimichi, Satoshi Azuma, Yasuhiko Hosokawa, Shinzo Tamai, Sadao Funahashi, Kotaro Higashi
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Publication number: 20160336874Abstract: An electric power conversion device includes a power conversion unit and a converter control unit. The power conversion unit includes three arms connected to an AC circuit. The converter control unit includes a phase DC voltage control unit, a negative sequence current command value calculation unit, an output current control unit, a circulating current control unit, a voltage command value calculation unit, and a gate signal generation unit, and imbalance of cell DC capacitor voltages among phases due to grid imbalance is controlled by circulating current and negative sequence current.Type: ApplicationFiled: July 2, 2014Publication date: November 17, 2016Applicants: MITSUBISHI ELECTRIC CORPORATION, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Takeshi KIKUCHI, Kaho MUKUNOKI, Toshiyuki FUJII, Osamu MORI, Shinzo TAMAI, Sadao FUNAHASHI, Yasuhiko HOSOKAWA, Kotaro HIGASHI
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Publication number: 20160329831Abstract: In a power conversion system in which one or more converter cells are connected in series to form an arm for each phase, a control device includes a voltage command generating unit for generating a positive arm voltage command and a negative arm voltage command for each phase. The voltage command generating unit includes an AC current control unit, a circulating current control unit, and a command distributing unit. On the basis of inputted voltage commands, the command distributing unit subtracts voltage drop portions due to inductance values in the arms from respective voltages assigned as outputs of the positive arm and the negative arm, to distribute voltage components, thereby determining the positive arm voltage command and the negative arm voltage command.Type: ApplicationFiled: December 3, 2014Publication date: November 10, 2016Applicants: Mitsubishi Electric Corporation, Toshiba Mitsubishi-Electric Industrial Systems CorporationInventors: Kaho MUKUNOKI, Toshiyuki FUJI, Osamu MORI, Shinzo TAMAI, Sadao FUNAHASHI, Yasuhiko HOSOKAWA, Kotaro HIGASHI
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Publication number: 20160190924Abstract: An electric power conversion device includes a plurality of cell converters connected in cascade and including main circuits, drive circuits, and self-feeding devices for supplying power to the drive circuits by being supplied with power from the main circuits. The drive circuit is supplied with power via a first feed line from the self-feeding device in the corresponding cell converter, and supplied with power from the self-feeding device in another cell converter via a second feed line on which an insulation input/output circuit is provided. When the self-feeding device is abnormal, the drive circuit is supplied with power from the self-feeding device in the other cell converter, whereby the electric power conversion device continuously provides a desired output.Type: ApplicationFiled: September 2, 2013Publication date: June 30, 2016Applicants: Mitsubishi Electric Corporation, Toshiba Mitsubishi-Electric Industrial Systems CorporationInventors: Kimiyuki KOYANAGI, Takushi JIMICHI, Satoshi AZUMA, Yasuhiko HOSOKAWA, Shinzo TAMAI, Sadao FUNAHASHI, Kotaro HIGASHI
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Publication number: 20160056727Abstract: A power conversion device includes: a DC current calculation unit for calculating a circulating current component for each phase which circulates between the phases through first arms and/or second arms not via an AC power supply and a DC power supply; and a circulating current control unit for controlling the circulating current component for each phase so as to follow a predetermined circulating current command value, thereby reliably suppressing variation in voltages of DC capacitors of unit cells among the phases even in such a case where an impedance is additionally inserted in a DC circuit.Type: ApplicationFiled: September 4, 2013Publication date: February 25, 2016Applicants: Mitsubishi Electric Corporation, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Kaho MUKUNOKI, Toshiyuki FUJII, Osamu MORI, Shinzo TAMAI, Sadao FUNAHASHI, Yasuhiko HOSOKAWA, Kotaro HIGASHI
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Publication number: 20160036314Abstract: A cell block including a plurality of cell converters connected in cascade and each including switching elements and a capacitor is provided. The cell block includes external connection terminals for connecting to another cell block in cascade, and a bypass circuit is connected to the external connection terminals.Type: ApplicationFiled: January 23, 2014Publication date: February 4, 2016Applicants: Mitsubishi Electric Corporation, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Kimiyuki KOYANAGI, Takushi JIMICHI, Satoshi AZUMA, Sadao FUNAHASHI, Yasuhiko HOSOKAWA, Shinzo TAMAI, Kotaro HIGASHI
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Patent number: 9154049Abstract: When switching control signals of self-excited semiconductor devices from OFF-control to ON-control, a control circuit controls the self-excited semiconductor device to be ON after a lapse of a turn-ON time from when a control voltage is applied to the self-excited semiconductor device. When switching the control signals of the self-excited semiconductor devices from ON-control to OFF-control, the control circuit controls the control signal of the self-excited semiconductor device to be OFF after a lapse of a turn-OFF time from when the control voltage is applied to the self-excited semiconductor device.Type: GrantFiled: May 10, 2012Date of Patent: October 6, 2015Assignee: TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventor: Kotaro Higashi
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Publication number: 20150188447Abstract: An electrical power converter includes: AC voltage terminals U, V, and W; DC voltage terminals P and N; a converter cell series unit composed of one or more converter cells connected in series between the AC voltage terminals U, V, and W and the DC voltage terminals P and N, each converter cell including a semiconductor element and a capacitor; and a first inductance connected in series to the converter cell series unit, between, of the DC voltage terminals P and N, a DC voltage terminal at the lowest potential with respect to the ground, and the AC voltage terminals U, V, and W.Type: ApplicationFiled: July 2, 2013Publication date: July 2, 2015Applicants: Mitsubishi Electric Corporation, Toshiba Mitsubishi-Electric Industrial Systems CorporationInventors: Takushi Jimichi, Kimiyuki Koyanagi, Satoshi Azuma, Sadao Funahashi, Shinzo Tamai, Yasuhiko Hosokawa, Kotaro Higashi
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Publication number: 20150124504Abstract: When switching control signals of self-excited semiconductor devices from OFF-control to ON-control, a control circuit controls the self-excited semiconductor device to be ON after a lapse of a turn-ON time from when a control voltage is applied to the self-excited semiconductor device. When switching the control signals of the self-excited semiconductor devices from ON-control to OFF-control, the control circuit controls the control signal of the self-excited semiconductor device to be OFF after a lapse of a turn-OFF time from when the control voltage is applied to the self-excited semiconductor device.Type: ApplicationFiled: May 10, 2012Publication date: May 7, 2015Applicant: TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventor: Kotaro Higashi
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Patent number: 8552696Abstract: A control device of a self-excited reactive power compensation apparatus controls a reactive current output from a self-excited converter to a power system. The control device includes a first reference generating unit, a second reference generating unit, and a selecting unit. The first reference generating unit generates a first voltage reference of an output voltage output from the self-excited converter, such that the reactive current detected by a reactive current detecting unit follows a current reference. The second reference generating unit generates a second voltage reference of the output voltage output from the self-excited converter, such that a value of the reactive current becomes a predetermined value. The selecting unit selects a maximum value from the first and second voltage references.Type: GrantFiled: November 12, 2008Date of Patent: October 8, 2013Assignee: Toshiba Mitsubishi-Electric Industrial Systems CorporationInventors: Naoki Morishima, Kotaro Higashi
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Publication number: 20110254517Abstract: A control device of a self-excited reactive power compensation apparatus controls a reactive current output from a self-excited converter to a power system. The control device includes a first reference generating unit, a second reference generating unit, and a selecting unit. The first reference generating unit generates a first voltage reference of an output voltage output from the self-excited converter, such that the reactive current detected by a reactive current detecting unit follows a current reference. The second reference generating unit generates a second voltage reference of the output voltage output from the self-excited converter, such that a value of the reactive current becomes a predetermined value. The selecting unit selects a maximum value from the first and second voltage references.Type: ApplicationFiled: November 12, 2008Publication date: October 20, 2011Applicant: TOSHIBA MITSUBISHI-ELECTRIC INDUS. SYS. CORP.Inventors: Naoki Morishima, Kotaro Higashi