Patents by Inventor Yasutoshi Miki

Yasutoshi Miki 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: 11873039
    Abstract: A motor control device includes a third harmonic calculation unit configured to calculate a first third harmonic on a basis of an average value between a voltage command value of a maximum phase with a maximum duty ratio and a voltage command value of a minimum phase with a minimum duty ratio among three-phase voltage command values; an amplitude calculation unit configured to calculate an amplitude of the three-phase voltage command values; a third harmonic conversion unit configured to convert the first third harmonic into a second third harmonic on a basis of the first third harmonic and the amplitude; a correction unit configured to correct the three-phase voltage command values by subtracting the second third harmonic from the three-phase voltage command values.
    Type: Grant
    Filed: October 2, 2020
    Date of Patent: January 16, 2024
    Assignee: NSK LTD.
    Inventors: Yasutoshi Miki, Masahiro Maeda
  • Patent number: 11827291
    Abstract: A motor control device includes a third harmonic calculation unit configured to calculate a first third harmonic on a basis of an average value between a voltage command value of a maximum phase with a maximum duty ratio and a voltage command value of a minimum phase with a minimum duty ratio among three-phase voltage command values; an amplitude calculation unit configured to calculate an amplitude of the three-phase voltage command values; a third harmonic conversion unit configured to convert the first third harmonic into a second third harmonic on a basis of the first third harmonic and the amplitude; a correction unit configured to correct the three-phase voltage command values by subtracting the second third harmonic from the three-phase voltage command values.
    Type: Grant
    Filed: October 2, 2020
    Date of Patent: November 28, 2023
    Assignee: NSK LTD.
    Inventors: Yasutoshi Miki, Masahiro Maeda
  • Publication number: 20220306186
    Abstract: A motor control device includes a third harmonic calculation unit (60) configured to calculate a first third harmonic on a basis of an average value between a voltage command value of a maximum phase with a maximum duty ratio and a voltage command value of a minimum phase with a minimum duty ratio among three-phase voltage command values; an amplitude calculation unit (61) configured to calculate an amplitude of the three-phase voltage command values; a third harmonic conversion unit (62, 62?, 63, 65-67) configured to convert the first third harmonic into a second third harmonic on a basis of the first third harmonic and the amplitude; a correction unit (64) configured to correct the three-phase voltage command values by subtracting the second third harmonic from the three-phase voltage command values.
    Type: Application
    Filed: October 2, 2020
    Publication date: September 29, 2022
    Applicant: NSK LTD.
    Inventors: Yasutoshi MIKI, Masahiro MAEDA
  • Patent number: 11104374
    Abstract: A motor control device including: a voltage command value calculation unit configured to calculate a voltage command value of voltage applied to a motor, based on a q-axis current command value and a d-axis current command value; a driving circuit configured to output driving power to the motor, based on the voltage command value; a d-axis current command value calculation unit configured to calculate the d-axis current command value limiting the voltage command value to a maximum voltage applicable to the driving circuit or less by field-weakening control; a d-axis current command value limitation unit configured to limit the d-axis current command value; and a q-axis current command value limitation unit configured to limit the q-axis current command value lest the voltage command value exceed the maximum voltage due to limitation of the d-axis current command value by the d-axis current command value limitation unit.
    Type: Grant
    Filed: July 12, 2019
    Date of Patent: August 31, 2021
    Assignee: NSK LTD.
    Inventor: Yasutoshi Miki
  • Patent number: 11104376
    Abstract: A power supply current control device including: a current limit value calculation unit configured to calculate a current limit value on a basis of a difference between a power supply voltage and a predetermined set voltage, a power supply current, and a resistance model representing a resistance component of the power supply circuit; a power supply current limit unit configured to limit a magnitude of the power supply current on a basis of the current limit value; a change rate limit value calculation unit configured to calculate a change rate limit value on a basis of the difference and a change speed of the power supply voltage; and a power supply current change rate limit unit configured to limit a change rate of the power supply current on a basis of the change rate limit value.
    Type: Grant
    Filed: February 7, 2020
    Date of Patent: August 31, 2021
    Assignee: NSK LTD.
    Inventor: Yasutoshi Miki
  • Publication number: 20210245799
    Abstract: A power supply current control device including: a current limit value calculation unit configured to calculate a current limit value on a basis of a difference between a power supply voltage and a predetermined set voltage, a power supply current, and a resistance model representing a resistance component of the power supply circuit; a power supply current limit unit configured to limit a magnitude of the power supply current on a basis of the current limit value; a change rate limit value calculation unit configured to calculate a change rate limit value on a basis of the difference and a change speed of the power supply voltage; and a power supply current change rate limit unit configured to limit a change rate of the power supply current on a basis of the change rate limit value.
    Type: Application
    Filed: February 7, 2020
    Publication date: August 12, 2021
    Applicant: NSK LTD.
    Inventor: Yasutoshi MIKI
  • Publication number: 20210214000
    Abstract: To limit d-axis current to an arbitrary value while avoiding duty saturation of a motor.
    Type: Application
    Filed: July 12, 2019
    Publication date: July 15, 2021
    Applicant: NSK LTD.
    Inventor: Yasutoshi MIKI
  • Patent number: 10972033
    Abstract: A motor control device including: a power supply voltage detection unit configured to detect a power supply voltage; a rotational angular velocity detection unit configured to detect a rotational angular velocity of the motor; a command value calculation unit configured to calculate a q-axis and d-axis current command values; a gain computation unit configured to compute, based on an upper limit value of power supply current supplied from a power supply to the motor, the power supply voltage, the rotational angular velocity, the q-axis current command value, and the d-axis current command value, a limit gain reducing the power supply current to the upper limit value or lower by limiting the q-axis current command value and the d-axis current command value; and a driving circuit configured to drive the motor, based on the q-axis current command value and the d-axis current command value limited by the limit gain.
    Type: Grant
    Filed: July 12, 2019
    Date of Patent: April 6, 2021
    Assignee: NSK LTD.
    Inventor: Yasutoshi Miki
  • Publication number: 20200274473
    Abstract: A motor control device including: a power supply voltage detection unit configured to detect a power supply voltage; a rotational angular velocity detection unit configured to detect a rotational angular velocity of the motor; a command value calculation unit configured to calculate a q-axis and d-axis current command values; a gain computation unit configured to compute, based on an upper limit value of power supply current supplied from a power supply to the motor, the power supply voltage, the rotational angular velocity, the q-axis current command value, and the d-axis current command value, a limit gain reducing the power supply current to the upper limit value or lower by limiting the q-axis current command value and the d-axis current command value; and a driving circuit configured to drive the motor, based on the q-axis current command value and the d-axis current command value limited by the limit gain.
    Type: Application
    Filed: July 12, 2019
    Publication date: August 27, 2020
    Applicant: NSK LTD.
    Inventor: Yasutoshi MIKI
  • Patent number: 8054340
    Abstract: An imaging device detects an occurrence of a trigger event, stores images before and after the trigger event occurrence for a specified time and transmits them to an image management server. The image management server stores the image file and key information associated with the image file, the key information including information related to timing of the trigger event occurrence related to the image in an image DB. When the image management server receives a search condition, the image management server obtains an image file stored in association with the key information satisfying the designated search condition from the image DB.
    Type: Grant
    Filed: January 22, 2008
    Date of Patent: November 8, 2011
    Assignee: Seiko Precision Inc.
    Inventors: Yasutoshi Miki, Hisanaga Tamura
  • Publication number: 20080174675
    Abstract: An imaging device detects an occurrence of a trigger event, stores images before and after the trigger event occurrence for a specified time and transmits them to an image management server. The image management server stores the image file and key information associated with the image file, the key information including information related to timing of the trigger event occurrence related to the image in an image DB. When the image management server receives a search condition, the image management server obtains an image file stored in association with the key information satisfying the designated search condition from the image DB.
    Type: Application
    Filed: January 22, 2008
    Publication date: July 24, 2008
    Applicant: SEIKO PRECISION INC.
    Inventors: Yasutoshi Miki, Hisanaga Tamura