Patents by Inventor Naoto Ohnuma

Naoto Ohnuma 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).

  • Publication number: 20220024720
    Abstract: An elevator according to an aspect of the present invention includes a car speed detection device that measures car speed, an emergency braking device that comes into press contact with a guiderail and emergently stops a car when the car speed exceeds a threshold, an electric actuating unit that electrically actuates the emergency braking device, a battery that supplies electric power when commercial power supply is interrupted, and a safety control unit that monitors abnormality of the elevator and controls operation of the electric actuating unit. The safety control unit measures remaining power of the battery when the electric power is supplied from the battery, determines operation propriety of the emergency braking device at commercial power supply restoration time based on transition of battery remaining power, and controls operation of the electric actuating unit at the commercial power supply restoration time based on content of the determination.
    Type: Application
    Filed: October 17, 2019
    Publication date: January 27, 2022
    Inventors: Takeshi KONDO, Shinsuke INOUE, Naoto OHNUMA, Yasutaka SUZUKI, Kohichiroh IDE
  • Patent number: 7199547
    Abstract: In order to control the position of a mobile body without using a position detector, a magnetic pole position of a rotor of a synchronous motor is estimated based on electrical quantities in relation to electric power supplied to the synchronous motor and then the mobile body position is estimated based on the estimated magnetic pole position.
    Type: Grant
    Filed: October 19, 2001
    Date of Patent: April 3, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Daigo Kaneko, Hiromi Inaba, Tsunehiro Endo, Ikuo Yamato, Naoto Ohnuma
  • Patent number: 6492790
    Abstract: A driving system for driving an AC motor, which is capable of promptly switching to an individual inverter operation mode, wherein a control instruction for each of a plurality of power converters is generated by summing outputs of a plurality of current compensation units connected in parallel, and each of the plurality of current compensation units makes compensation to reduce a deviation of a detected output current value of an associated power converter from a current instruction value to be outputted from the power converter to zero.
    Type: Grant
    Filed: February 26, 2001
    Date of Patent: December 10, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Toshifumi Yoshikawa, Naoto Ohnuma, Toshisuke Mine, Takao Kishikawa, Sadao Hokari
  • Publication number: 20020175651
    Abstract: In order to control the position of a mobile body without using a position detector, a magnetic pole position of a rotor of a synchronous motor is estimated based on electrical quantities in relation to electric power supplied to the synchronous motor and then the mobile body position is estimated based on the estimated magnetic pole position.
    Type: Application
    Filed: October 19, 2001
    Publication date: November 28, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Daigo Kaneko, Hiromi Inaba, Tsunehiro Endo, Ikuo Yamato, Naoto Ohnuma
  • Publication number: 20020005704
    Abstract: A driving system for driving an AC motor, which is capable of promptly switching to an individual inverter operation mode, wherein a control instruction for each of a plurality of power converters is generated by summing outputs of a plurality of current compensation units connected in parallel, and each of the plurality of current compensation units makes compensation to reduce a deviation of a detected output current value of an associated power converter from a current instruction value to be outputted from the power converter to zero.
    Type: Application
    Filed: February 26, 2001
    Publication date: January 17, 2002
    Inventors: Toshifumi Yoshikawa, Naoto Ohnuma, Toshisuke Mine, Takao Kishikawa, Sadao Hokari