Patents by Inventor Yuji Yamasawa

Yuji Yamasawa 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).

  • Motor speed control method and apparatus with drooping compensation independent of acceleration or deceleration current and time constant of motor
    Patent number: 5256944
    Abstract: A speed control method and apparatus for a motor driven by output of a power conversion unit, wherein a first current command value is inputted to derive a drooping variable, a deviation between a detected speed value of the motor and a speed command value is derived, the first current command value is derived on the basis of a value obtained by compensating the deviation with the drooping variable, the speed command value is inputted to derive an acceleration or deceleration current value for accelerating or decelerating the motor, and the first current command value and the acceleration or deceleration current value are added together to derive a second current command value and control the output current of the power conversion unit on the basis of the second current command value.
    Type: Grant
    Filed: September 9, 1991
    Date of Patent: October 26, 1993
    Assignees: Hitachi, Ltd., Kawasaki Steel Corporation
    Inventors: Masahiro Tobise, Itsuo Shimizu, Yuji Yamasawa, Toshihiko Chino