Patents by Inventor Koroku NISHIZAWA

Koroku NISHIZAWA 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).

  • Three-phase inverter with reduced DC bus capacitor ripple
    Patent number: 10778116
    Abstract: A three-phase inverter includes three series circuits that are connected in parallel to a capacitor connected in parallel to a DC voltage source. Each of the three series circuits includes two semiconductor switching elements connected in series. A connection point between the two semiconductor switching elements is used as an AC output terminal for each phase. The three-phase inverter generates PWM pulses of three phases including a PWM pulse of one phase, whose pulse width of a positive side pulse in one switching cycle is the largest, and including PWM pulses of the other two phases such that a positional relationship between positive side pulses of the other two phases is a positional relationship in which an overlapping range on a time axis is smaller as compared with a state in which a positive side pulse of one phase encompasses a positive side pulse of the other pulse.
    Type: Grant
    Filed: February 19, 2019
    Date of Patent: September 15, 2020
    Assignees: National University Corporation Nagaoka University of Technology, FUJI ELECTRIC CO., LTD.
    Inventors: Junichi Itoh, Koroku Nishizawa, Akio Toba, Akihiro Odaka
  • THREE-PHASE INVERTER
    Publication number: 20190334454
    Abstract: A three-phase inverter includes three series circuits that are connected in parallel to a capacitor connected in parallel to a DC voltage source. Each of the three series circuits includes two semiconductor switching elements connected in series. A connection point between the two semiconductor switching elements is used as an AC output terminal for each phase. The three-phase inverter generates PWM pulses of three phases including a PWM pulse of one phase, whose pulse width of a positive side pulse in one switching cycle is the largest, and including PWM pulses of the other two phases such that a positional relationship between positive side pulses of the other two phases is a positional relationship in which an overlapping range on a time axis is smaller as compared with a state in which a positive side pulse of one phase encompasses a positive side pulse of the other pulse.
    Type: Application
    Filed: February 19, 2019
    Publication date: October 31, 2019
    Inventors: Junichi ITOH, Koroku NISHIZAWA, Akio TOBA, Akihiro ODAKA