Patents by Inventor Hirohiko Tsutsumi

Hirohiko Tsutsumi 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).

  • Method and apparatus for protecting switching element of inverter from being overheated
    Patent number: 5875414
    Abstract: In a method and apparatus for protecting a plurality of same semiconductor switching elements used in a PWM inverter from being overheated, a junction temperature rise T.sub.n of one of the switching elements is derived on the basis of an output frequency of the inverter (.omega. c), an output current (I) of the inverter, and a control factor (a) and when T.sub.n >T.sub.nref, the overheat in the corresponding switching element occurs so that a gate signal for each switching element is not inputted or an PWM off duty ratio on a pulse duty ratio of the gate signal is increased to limit the output current of the inverter.
    Type: Grant
    Filed: February 20, 1997
    Date of Patent: February 23, 1999
    Assignee: Kabushiki Kaisha Meidensha
    Inventor: Hirohiko Tsutsumi