Patents by Inventor Koji Temma
Koji Temma 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: 7919951Abstract: In a system stabilizing control system of controlling reactive power by a reactive power compensating device according to a voltage variation of an electric power system in which a capacitor is connected to a bus through a breaker, when the bus voltage drops, the capacitor is closed through the breaker to suppress a leading compensation reactive power amount caused by the reactive power compensating device, and when the bus voltage rises, the capacitor is disconnected through the breaker to suppress a lagging compensation reactive power amount caused by the reactive power compensating device.Type: GrantFiled: May 23, 2007Date of Patent: April 5, 2011Assignee: Mitsubishi Electric CorporationInventors: Naohiro Toki, Masatoshi Takeda, Yoshiyuki Kono, Koji Temma
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Patent number: 7688043Abstract: In a conventional reactive-power compensator using a static reactive-power compensator (SVC), there are many cases in which the SVC is operating in a state in which it generates an amount of reactive power equivalent to a large part of its capacity. When an unforeseen large voltage fluctuation occurs in this state, the SVC can not sufficiently generate the amount of reactive power required to mitigate the voltage fluctuation. In some cases, such a voltage fluctuation can not be brought under control. To address this situation, a reactive-power compensator utilizes a reactive-power control apparatus that includes a comparison voltage generator for generating, for a control target voltage and to mitigate voltage fluctuation, a comparison voltage restricted within predetermined limits and obeying a predetermined time-lag characteristic. A differential voltage generator generates a differential voltage that is the difference between the comparison voltage and the control target voltage.Type: GrantFiled: June 25, 2007Date of Patent: March 30, 2010Assignee: Mitsubishi Electric CorporationInventors: Naohiro Toki, Masatoshi Takeda, Yoshiyuki Kono, Koji Temma
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Patent number: 7683589Abstract: A reactive power compensator includes a control block with a limiter and a primary delay-control block with a limiter that set, based on an output of a voltage sensor, reactive power produced by an SVC to a predetermined value. A reactive power controller sets the reactive power produced by the SVC to the predetermined value controls a voltage of a second bus to fall within a predetermined range. This is performed by adjusting an initial value of the reactive power that is output by the SVC, when a bus voltage of the second bus laid at a position apart from a first bus that is laid at a position near the SVC is deviated from a predetermined fixed range.Type: GrantFiled: November 21, 2007Date of Patent: March 23, 2010Assignee: Mitsubishi Electric CorporationInventors: Koji Temma, Yoshiyuki Kono
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Patent number: 7638986Abstract: In a control system for a static var compensator that performs phase control of a current of a reactor for each phase by a thyristor and thus controls reactive power, a detecting unit that detects a tertiary harmonic current flowing through each phase of the static var compensator is provided, and on the basis of the tertiary harmonic current flowing through each phase detected by the detecting unit, the thyristor of each phase is controlled so that the quantity of generated tertiary harmonic current of each phase becomes equal, and therefore an outflow of the tertiary harmonic current toward a system can be restrained by an inexpensive method.Type: GrantFiled: June 1, 2007Date of Patent: December 29, 2009Assignee: Mitsubishi Electric CorporationInventors: Masatoshi Takeda, Koji Temma
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Publication number: 20090001942Abstract: A reactive power compensator includes a control block with a limiter and a primary delay-control block with a limiter that set, based on an output of a voltage sensor, reactive power produced by an SVC to a predetermined value. A reactive power controller sets the reactive power produced by the SVC to the predetermined value controls a voltage of a second bus to fall within a predetermined range. This is performed by adjusting an initial value of the reactive power that is output by the SVC, when a bus voltage of the second bus laid at a position apart from a first bus that is laid at a position near the SVC is deviated from a predetermined fixed range.Type: ApplicationFiled: November 21, 2007Publication date: January 1, 2009Applicant: Mitsubishi Electric CorporationInventors: Koji Temma, Yoshiyuki Kono
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Publication number: 20080157728Abstract: In a conventional reactive-power compensator using a static reactive-power compensator (SVC), there are many cases in which the SVC is operating in a state in which it generates an amount of reactive power equivalent to a large part of its capacity. When an unforeseen large voltage fluctuation occurs in this state, the SVC can not sufficiently generate the amount of reactive power required to mitigate the voltage fluctuation. In some cases, such a voltage fluctuation can not be brought under control. To address this situation, a reactive-power compensator utilizes a reactive-power control apparatus that includes a comparison voltage generator for generating, for a control target voltage and to mitigate voltage fluctuation, a comparison voltage restricted within predetermined limits and obeying a predetermined time-lag characteristic. A differential voltage generator generates a differential voltage that is the difference between the comparison voltage and the control target voltage.Type: ApplicationFiled: June 25, 2007Publication date: July 3, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Naohiro Toki, Masatoshi Takeda, Yoshiyuki Kono, Koji Temma
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Publication number: 20080001581Abstract: In a control system for a static var compensator that performs phase control of a current of a reactor for each phase by a thyristor and thus controls reactive power, a detecting unit that detects a tertiary harmonic current flowing through each phase of the static var compensator is provided, and on the basis of the tertiary harmonic current flowing through each phase detected by the detecting unit, the thyristor of each phase is controlled so that the quantity of generated tertiary harmonic current of each phase becomes equal, and therefore an outflow of the tertiary harmonic current toward a system can be restrained by an inexpensive method.Type: ApplicationFiled: June 1, 2007Publication date: January 3, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Masatoshi Takeda, Koji Temma
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Publication number: 20070279016Abstract: In a system stabilizing control system of controlling reactive power by a reactive power compensating device according to a voltage variation of an electric power system in which a capacitor is connected to a bus through a breaker, when the bus voltage drops, the capacitor is closed through the breaker to suppress a leading compensation reactive power amount caused by the reactive power compensating device, and when the bus voltage rises, the capacitor is disconnected through the breaker to suppress a lagging compensation reactive power amount caused by the reactive power compensating device.Type: ApplicationFiled: May 23, 2007Publication date: December 6, 2007Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Naohiro Toki, Masatoshi Takeda, Yoshiyuki Kono, Koji Temma
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Patent number: 6680602Abstract: When a voltage of a system is stabilized by connecting the system with two types of voltage regulators, i.e., a slow-response tap-changing transformer and a quick-response reactive power regulator, it is not always clear how characteristics of the reactive power regulator should be regulated. Moreover, the regulation takes much time. In a range where voltage fluctuation of the system is small and a tap-changing transformer can cope with the change, gain of a reactive power regulator is set to be low, and its output is restrained. In a range where voltage fluctuation of the system is large and the voltage deviates from a width of a dead zone of the tap-changing transformer, gain of the reactive power regulator is set to be high, and regulating current is fully utilized.Type: GrantFiled: July 22, 2002Date of Patent: January 20, 2004Assignees: Mitsubishi Denki Kabushiki Kaisha, The Kansai Electric Power Co., Inc.Inventors: Isao Iyoda, Koji Temma, Katsuhiko Matsuno, Yoshinao Matsushita
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Publication number: 20030122528Abstract: When a voltage of a system is stabilized by connecting the system with two types of voltage regulators, i.e., a slow-response tap-changing transformer and a quick-response reactive power regulator, it is not always clear how characteristics of the reactive power regulator should be regulated, and moreover, the regulation takes much time. In a range where voltage fluctuation of the system is small and a tap-changing transformer 17 can cope with the change, gain of a reactive power regulator 1 is set to be low, and its output is restrained. In a range where voltage fluctuation of the system is large and the voltage deviates from a width of a dead zone of the tap-changing transformer, gain of the reactive power regulator 1 is set to be high, and a regulating current is fully utilized.Type: ApplicationFiled: July 22, 2002Publication date: July 3, 2003Applicant: Mitsubishi Denki Kabushiki KaishaInventors: Isao Iyoda, Koji Temma, Katsuhiko Matsuno, Yoshinao Matsushita