Patents by Inventor Masahiro Nagasu
Masahiro Nagasu 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: 7046155Abstract: A fault detection system detecting malfunctions or deteriorations, which may result in an inverter fault, is provided. The system has a temperature sensor installed on a semiconductor module to monitor a temperature rise rate. It is judged that an abnormal condition has occurred if the thermal resistance is increased by the deterioration of a soldering layer of the semiconductor module or by drive circuit malfunctions and, as a result, the relation between an operation mode and the temperature rise rate falls outside a predetermined range.Type: GrantFiled: June 1, 2004Date of Patent: May 16, 2006Assignee: Hitachi, Ltd.Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
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Publication number: 20040221217Abstract: A fault detection system detecting malfunctions or deteriorations, which may result in an inverter fault, is provided. The system has a temperature sensor installed on a semiconductor module to monitor a temperature rise rate. It is judged that an abnormal condition has occurred if the thermal resistance is increased by the deterioration of a soldering layer of the semiconductor module or by drive circuit malfunctions and, as a result, the relation between an operation mode and the temperature rise rate falls outside a predetermined range.Type: ApplicationFiled: June 1, 2004Publication date: November 4, 2004Applicant: HITACHI, LTD.Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
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Patent number: 6759964Abstract: A fault detection system detecting malfunctions or deteriorations, which may result in an inverter fault, is provided. The system has a temperature sensor installed on a semiconductor module to monitor a temperature rise rate. It is judged that an abnormal condition has occurred if the thermal resistance is increased by the deterioration of a soldering layer of the semiconductor module or by drive circuit malfunctions and, as a result, the relation between an operation mode and the temperature rise rate falls outside a predetermined range.Type: GrantFiled: March 18, 2002Date of Patent: July 6, 2004Assignee: Hitachi, Ltd.Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
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Publication number: 20040103113Abstract: The present invention provides a high reliability information transmission system which can continue transmission at the occurrence of multiple failures.Type: ApplicationFiled: November 19, 2003Publication date: May 27, 2004Inventors: Yutaka Sato, Masahiro Nagasu, Shigenobu Yanai, Keiji Ishida, Toshiyuki Murakami
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Patent number: 6724313Abstract: A fault detection system detecting malfunctions or deteriorations, which may result in an inverter fault, is provided. The system has a temperature sensor installed on a semiconductor module to monitor a temperature rise rate. It is judged that an abnormal condition has occurred if the thermal resistance is increased by the deterioration of a soldering layer of the semiconductor module or by drive circuit malfunctions and, as a result, the relation between an operation mode and the temperature rise rate falls outside a predetermined range.Type: GrantFiled: August 9, 2002Date of Patent: April 20, 2004Assignee: Hitachi, Ltd.Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
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Publication number: 20040056702Abstract: A semiconductor circuit or a semiconductor device has the current-voltage characteristic that, in a blocking state of the semiconductor circuit or the semiconductor device, a current gently flows for values of a voltage equal to or greater than a first voltage value but equal to or smaller than a second voltage value, whereas a current abruptly flows for values of a voltage greater than the second voltage value. Due to the current-voltage characteristic, energy accumulated in an inductance provided within the circuit is consumed by a differential resistance of the semiconductor circuit or a semiconductor, thereby preventing the occurrence of the electromagnetic noise and an excessively large voltage.Type: ApplicationFiled: September 24, 2003Publication date: March 25, 2004Inventors: Masahiro Nagasu, Hideo Kobayashi, Hideki Miyazaki, Shin Kimura, Junichi Sakano, Mutsuhiro Mori
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Patent number: 6600978Abstract: A railway vehicle operation-control system includes at least one central processing unit being connected to a plurality of devices, which are connected in parallel, via information communication means, the plurality of the devices having at least one operational state-monitoring function which transmits information on operational states of each device to the central processing unit; wherein a total controlled-variable necessary for the system is attained by allocating the total control variable to each device based on operational states determined from results of monitoring performed by the operational state-monitoring function, and a performance margin which is defined as a difference between a permissible power-output value and a current power-output value for each device while monitoring and reflecting the performance margin of each device.Type: GrantFiled: December 13, 2001Date of Patent: July 29, 2003Assignee: Hitachi, Ltd.Inventors: Masahiro Nagasu, Yutaka Sato, Shin Kimura, Kiyoshi Nakata
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Publication number: 20030076233Abstract: A fault detection system detecting malfunctions or deteriorations, which may result in an inverter fault, is provided. The system has a temperature sensor installed on a semiconductor module to monitor a temperature rise rate. It is judged that an abnormal condition has occurred if the thermal resistance is increased by the deterioration of a soldering layer of the semiconductor module or by drive circuit malfunctions and, as a result, the relation between an operation mode and the temperature rise rate falls outside a predetermined range.Type: ApplicationFiled: August 9, 2002Publication date: April 24, 2003Applicant: HITACHI, LTD.Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
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Publication number: 20030076232Abstract: A fault detection system detecting malfunctions or deteriorations, which may result in an inverter fault, is provided. The system has a temperature sensor installed on a semiconductor module to monitor a temperature rise rate. It is judged that an abnormal condition had occurred if the thermal resistance is increased by the deterioration of a soldering layer of the semiconductor module or by drive circuit malfunctions and, as a result, the relation between an operation mode and the temperature rise rate falls outside a predetermined range.Type: ApplicationFiled: March 18, 2002Publication date: April 24, 2003Applicant: Hitachi, Ltd.Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
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Publication number: 20020161490Abstract: A railway vehicle operation-control system includes at least one central processing unit being connected to a plurality of devices, which are connected in parallel, via information communication means, the plurality of the devices having at least one operational state-monitoring function which transmits information on operational states of each device to the central processing unit; wherein a total controlled-variable necessary for the system is attained by allocating the total control variable to each device based on operational states determined from results of monitoring performed by the operational state-monitoring function, and a performance margin which is defined as a difference between a permissible power-output value and a current power-output value for each device while monitoring and reflecting the performance margin of each device.Type: ApplicationFiled: December 13, 2001Publication date: October 31, 2002Applicant: Hitachi, Ltd.Inventors: Masahiro Nagasu, Yutaka Sato, Shin Kimura, Kiyoshi Nakata
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Publication number: 20020145188Abstract: Control electrode wirings which are led out from control electrodes over a number of chips built in a flat package and insulating members which are provided in order to insulate the control electrode wirings from main electrode wirings are also given function of positioning of the respective semiconductor chips in the flat package. Further, a one-piece control electrode wiring net is housed in the common electrodes of the package and the electrodes which are led out from the control electrodes of the respective semiconductor chips are connected to the net to simplify the processing of a large number of gate signal wirings.Type: ApplicationFiled: June 5, 2002Publication date: October 10, 2002Inventors: Hironori Kodama, Masahiro Nagasu, Hirokazu Inoue, Yasuo Osone, Shigeta Ueda, Kazuji Yamada
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Patent number: 6452261Abstract: Control electrode wirings which are led out from control electrodes over a number of chips built in a flat package and insulating members which are provided in order to insulate the control electrode wirings from main electrode wirings are also given function of positioning of the respective semiconductor chips in the flat package. Further, a one-piece control electrode wiring net is housed in the common electrodes of the package and the electrodes which are led out from the control electrodes of the respective semiconductor chips are connected to the net to simplify the processing of a large number of gate signal wirings.Type: GrantFiled: September 7, 1999Date of Patent: September 17, 2002Assignee: Hitachi, Ltd.Inventors: Hironori Kodama, Masahiro Nagasu, Hirokazu Inoue, Yasuo Osone, Shigeta Ueda, Kazuji Yamada
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Publication number: 20020125548Abstract: A semiconductor circuit or a semiconductor device has the current-voltage characteristic that, in a blocking state of the semiconductor circuit or the semiconductor device, a current gently flows for values of a voltage equal to or greater than a first voltage value but equal to or smaller than a second voltage value, whereas a current abruptly flows for values of a voltage greater than the second voltage value. Due to the current-voltage characteristic, energy accumulated in an inductance provided within the circuit is consumed by a differential resistance of the semiconductor circuit or a semiconductor, thereby preventing the occurrence of the electromagnetic noise and an excessively large voltage.Type: ApplicationFiled: May 1, 2002Publication date: September 12, 2002Inventors: Masahiro Nagasu, Hideo Kobayashi, Hideki Miyazaki, Shin Kimura, Junichi Sakano, Mutsuhiro Mori
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Patent number: 6414370Abstract: A semiconductor circuit or a semiconductor device has the current-voltage characteristic that, in a blocking-state of the semiconductor circuit or the semiconductor device, a current gently flows for values of a voltage equal to or greater than a first voltage value but equal to or smaller than a second voltage value, whereas a current abruptly flows for values of a voltage greater than the second voltage value. Due to the current-voltage characteristic, energy accumulated in an inductance provided within the circuit is consumed by a differential resistance of the semiconductor circuit or a semiconductor, thereby preventing the occurrence of the electromagnetic noise and an excessively large voltage.Type: GrantFiled: August 17, 2000Date of Patent: July 2, 2002Assignee: Hitachi, Ltd.Inventors: Masahiro Nagasu, Hideo Kobayashi, Hideki Miyazaki, Shin Kimura, Junichi Sakano, Mutsuhiro Mori
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Publication number: 20020062182Abstract: A support system for recovering a train in which the amount of information to be transmitted from the train to a train-running management system and maintenance factory can be reduced. At the time of transmitting information on a failure from the train to a plurality of ground facilities, information is analyzed and processed in the train according to different transmission destinations, and necessary information is transmitted to the ground facilities. Thereby the amount of communication between the ground facilities and train can be made small and the amount of information to be processed in the ground facilities can be reduced.Type: ApplicationFiled: February 26, 2001Publication date: May 23, 2002Inventors: Yutaka Sato, Masahiro Nagasu, Dai Watanabe
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Patent number: 6380796Abstract: A semiconductor power converting apparatus includes a semiconductor element for controlling a current flowing between a collector and an emitter in response to a gate condition, a driving device connected to the gate, for driving the gate in response to a drive signal entered thereinto, a voltage applying device for applying both a forward bias and a reverse bias to the gate so as to set the emitter of the semiconductor element to a neutral potential, and a voltage dividing device for dividing a voltage appearing between the collector and the emitter of the semiconductor element, in which the drive signal is under OFF state, a voltage produced based upon the divided voltage by the voltage dividing device is applied to the gate, and the gate voltage is controlled in response to the voltage appearing between the collector and the emitter of the semiconductor element, thereby reducing the snubbed loss.Type: GrantFiled: April 20, 2001Date of Patent: April 30, 2002Assignee: Hitachi, Ltd.Inventors: Hiromitsu Sakai, Hidetoshi Aizawa, Shuji Katoh, Ryuji Iyotani, Masahiro Nagasu
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Patent number: 6304472Abstract: In order to detect a current with high accuracy in an electric power converting system, an inductor is connected to a main terminal of a switching element in series, and a voltage generated in both ends of the inductor during switching period is integrated using an integrating circuit to detect the current.Type: GrantFiled: May 12, 2000Date of Patent: October 16, 2001Assignee: Hitachi, Ltd.Inventors: Masahiro Nagasu, Shin Kimura, Mutsuhiro Mori, Kiyoshi Nakata, Mutsuhiro Terunuma
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Publication number: 20010015670Abstract: A semiconductor power converting apparatus includes a semiconductor element for controlling a current flowing between a collector and an emitter in response to a gate condition, a driving device connected to the gate, for driving the gate in response to a drive signal entered thereinto, a voltage applying device for applying both a forward bias and a reverse bias to the gate so as to set the emitter of the semiconductor element to a neutral potential, and a voltage dividing device for dividing a voltage appearing between the collector and the emitter of the semiconductor element, in which the drive signal is under OFF state, a voltage produced based upon the divided voltage by the voltage dividing device is applied to the gate, and the gate voltage is controlled in response to the voltage appearing between the collector and the emitter of the semiconductor element, thereby reducing the snubbed loss.Type: ApplicationFiled: April 20, 2001Publication date: August 23, 2001Applicant: Hitachi, Ltd.Inventors: Hiromitsu Sakai, Hidetoshi Aizawa, Shuji Katoh, Ryuji Iyotani, Masahiro Nagasu
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Patent number: 6271709Abstract: A gate drive circuit of a voltage drive switching element, which is characterized by control of di/dt and dv/dt when an IGBT is switched by controlling increases in the switching time and loss of the IGBT, includes a drive means for amplifying a signal for controlling the switching operation of a voltage drive switching device including the IGBT, a means for detecting the gate voltage of the IGBT, a voltage decrease (increase) means for slowly decreasing (increasing) the output voltage when the drive means is turned on (off) in the course of time, and a voltage increase (decrease) means for slowly increasing (decreasing) the output voltage. By switching from the voltage decrease (increase) means to the voltage increase (decrease) means according to the detected value of the gate voltage of the IGBT, di/dt and dv/dt are controlled when the IGBT is turned on (off).Type: GrantFiled: December 3, 1999Date of Patent: August 7, 2001Assignee: Hitachi, LTDInventors: Shin Kimura, Masahiro Nagasu, Satoru Inarida, Hideki Miyazaki, Katsunori Suzuki
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Patent number: 6242968Abstract: A semiconductor power converting apparatus includes a semiconductor element for controlling a current flowing between a collector and an emitter in response to a gate condition, a driving device connected to the gate, for driving the gate in response to a drive signal entered thereinto, a voltage applying device for applying both a forward bias and a reverse bias to the gate so as to set the emitter of the semiconductor element to a neutral potential, and a voltage dividing device for dividing a voltage appearing between the collector and the emitter of the semiconductor element, in which the drive signal is under OFF state, a voltage produced based upon the divided voltage by the voltage dividing device is applied to the gate, and the gate voltage is controlled in response to the voltage appearing between the collector and the emitter of the semiconductor element, thereby reducing the snubbed loss.Type: GrantFiled: August 22, 2000Date of Patent: June 5, 2001Assignee: Hitachi, Ltd.Inventors: Hiromitsu Sakai, Hidetoshi Aizawa, Shuji Katoh, Ryuji Iyotani, Masahiro Nagasu