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).

  • Patent number: 7046155
    Abstract: 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: Grant
    Filed: June 1, 2004
    Date of Patent: May 16, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
  • Publication number: 20040221217
    Abstract: 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: Application
    Filed: June 1, 2004
    Publication date: November 4, 2004
    Applicant: HITACHI, LTD.
    Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
  • Patent number: 6759964
    Abstract: 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: Grant
    Filed: March 18, 2002
    Date of Patent: July 6, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
  • Publication number: 20040103113
    Abstract: The present invention provides a high reliability information transmission system which can continue transmission at the occurrence of multiple failures.
    Type: Application
    Filed: November 19, 2003
    Publication date: May 27, 2004
    Inventors: Yutaka Sato, Masahiro Nagasu, Shigenobu Yanai, Keiji Ishida, Toshiyuki Murakami
  • Patent number: 6724313
    Abstract: 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: Grant
    Filed: August 9, 2002
    Date of Patent: April 20, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
  • Publication number: 20040056702
    Abstract: 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: Application
    Filed: September 24, 2003
    Publication date: March 25, 2004
    Inventors: Masahiro Nagasu, Hideo Kobayashi, Hideki Miyazaki, Shin Kimura, Junichi Sakano, Mutsuhiro Mori
  • Patent number: 6600978
    Abstract: 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: Grant
    Filed: December 13, 2001
    Date of Patent: July 29, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Nagasu, Yutaka Sato, Shin Kimura, Kiyoshi Nakata
  • Publication number: 20030076233
    Abstract: 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: Application
    Filed: August 9, 2002
    Publication date: April 24, 2003
    Applicant: HITACHI, LTD.
    Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
  • Publication number: 20030076232
    Abstract: 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: Application
    Filed: March 18, 2002
    Publication date: April 24, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Yutaka Sato, Masahiro Nagasu, Katsumi Ishikawa, Ryuichi Saito, Satoru Inarida
  • Publication number: 20020161490
    Abstract: 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: Application
    Filed: December 13, 2001
    Publication date: October 31, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Masahiro Nagasu, Yutaka Sato, Shin Kimura, Kiyoshi Nakata
  • Publication number: 20020145188
    Abstract: 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: Application
    Filed: June 5, 2002
    Publication date: October 10, 2002
    Inventors: Hironori Kodama, Masahiro Nagasu, Hirokazu Inoue, Yasuo Osone, Shigeta Ueda, Kazuji Yamada
  • Patent number: 6452261
    Abstract: 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: Grant
    Filed: September 7, 1999
    Date of Patent: September 17, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Hironori Kodama, Masahiro Nagasu, Hirokazu Inoue, Yasuo Osone, Shigeta Ueda, Kazuji Yamada
  • Publication number: 20020125548
    Abstract: 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: Application
    Filed: May 1, 2002
    Publication date: September 12, 2002
    Inventors: Masahiro Nagasu, Hideo Kobayashi, Hideki Miyazaki, Shin Kimura, Junichi Sakano, Mutsuhiro Mori
  • Patent number: 6414370
    Abstract: 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: Grant
    Filed: August 17, 2000
    Date of Patent: July 2, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Nagasu, Hideo Kobayashi, Hideki Miyazaki, Shin Kimura, Junichi Sakano, Mutsuhiro Mori
  • Publication number: 20020062182
    Abstract: 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: Application
    Filed: February 26, 2001
    Publication date: May 23, 2002
    Inventors: Yutaka Sato, Masahiro Nagasu, Dai Watanabe
  • Patent number: 6380796
    Abstract: 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: Grant
    Filed: April 20, 2001
    Date of Patent: April 30, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Hiromitsu Sakai, Hidetoshi Aizawa, Shuji Katoh, Ryuji Iyotani, Masahiro Nagasu
  • Patent number: 6304472
    Abstract: 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: Grant
    Filed: May 12, 2000
    Date of Patent: October 16, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Nagasu, Shin Kimura, Mutsuhiro Mori, Kiyoshi Nakata, Mutsuhiro Terunuma
  • Publication number: 20010015670
    Abstract: 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: Application
    Filed: April 20, 2001
    Publication date: August 23, 2001
    Applicant: Hitachi, Ltd.
    Inventors: Hiromitsu Sakai, Hidetoshi Aizawa, Shuji Katoh, Ryuji Iyotani, Masahiro Nagasu
  • Patent number: 6271709
    Abstract: 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: Grant
    Filed: December 3, 1999
    Date of Patent: August 7, 2001
    Assignee: Hitachi, LTD
    Inventors: Shin Kimura, Masahiro Nagasu, Satoru Inarida, Hideki Miyazaki, Katsunori Suzuki
  • Patent number: 6242968
    Abstract: 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: Grant
    Filed: August 22, 2000
    Date of Patent: June 5, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Hiromitsu Sakai, Hidetoshi Aizawa, Shuji Katoh, Ryuji Iyotani, Masahiro Nagasu