Patents by Inventor Jinkoo Choo

Jinkoo Choo 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: 4785225
    Abstract: A control apparatus for an induction motor comprises a variable voltage, variable frequency inverter feeding the motor, which is controlled by the PWM control. A secondary current component and an exciting current component of the motor are obtained by the calculation on the basis of a motor current and an actual slip frequency of the motor. From the thus obtained secondary current component, an actual torque produced by the motor is calculated. A frequency reference for the PWM control is obtained by the comparison result of the actual torque and a torque reference. A modulation factor reference for the PWM control is obtained by the comparison of the exciting current component and an exciting current reference. According to this control apparatus, the torque of the induction motor can be controlled to follow the torque reference with a high accuracy.
    Type: Grant
    Filed: October 7, 1987
    Date of Patent: November 15, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Akira Horie, Yoshiji Jimbo, Kingo Abe, Jinkoo Choo, Seiki Amikura, Yozo Tsuzuki