Patents by Inventor Youuji Ishida

Youuji Ishida 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).

  • Circuit for controlling an electric power supply apparatus, a method therefor and an uninterruptible power supply
    Patent number: 5115386
    Abstract: A mathematical model for simulating a dynamic characteristic of an electric power supply apparatus, a model control function for controlling an output from the mathematical model in a closed loop fashion and an electric power supply apparatus control function for approximating a control variable for the electric power supply apparatus to a reference value are provided in a control circuit, wherein an output from the mathematical model is output as a pulse width reference signal, and the pulse width reference signal is corrected by an on-delay portion due to switching elements by means of a gain revision circuit, thereby promptly and stably controlling the electric power supply apparatus.
    Type: Grant
    Filed: October 15, 1990
    Date of Patent: May 19, 1992
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Hidefumi Shirahama, Ikuo Yamato, Norikazu Tokunaga, Yasuo Matsuda, Mitsufumi Iwanaka, Takeshi Nagano, Youuji Ishida