Patents by Inventor Rikio Yoshikawa

Rikio Yoshikawa 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: 8779701
    Abstract: A sinusoidal signal is superimposed on a current command value of a q-axis (torque shaft) supplied from a host, and according to the resulting current command value, the output voltage of a power converter is controlled. For the calculation of the superimposed signal added to the current command value of the q-axis, with the use of the ripple component information of induced voltage coefficients of the d-axis and q-axis of the rotating coordinate system of a permanent magnet motor, the current command values of the d-axis and q-axis, an average value of induced voltage coefficients of the d-axis, and inductance values of the d-axis and q-axis, the sinusoidal superimposed signal is calculated and added to the above-described current command value of the q-axis.
    Type: Grant
    Filed: February 17, 2011
    Date of Patent: July 15, 2014
    Assignee: Kokusan Denki Co., Ltd.
    Inventors: Kazuaki Tobari, Rikio Yoshikawa, Katsuhiro Mochizuki
  • Patent number: 8410735
    Abstract: A torque ripple suppression control device for a permanent magnet motor includes a current command conversion unit that outputs a current command value, a position detector that detects a rotational position of the permanent magnet motor, a current detection unit that detects a current at the permanent magnet motor, an induced voltage coefficient setting unit that outputs an information signal related to an induced voltage coefficient for an induced voltage at the permanent magnet motor, a torque ripple suppression operation unit that outputs a current correction command value for the permanent magnet motor, a current control operation unit that outputs a voltage command value based upon addition results obtained by adding together the current command value and the current correction command value and the current detection value, and a power converter that outputs a voltage with which the permanent magnet motor is to be driven.
    Type: Grant
    Filed: January 19, 2011
    Date of Patent: April 2, 2013
    Assignee: Kokusan Denki Co., Ltd.
    Inventors: Kazuaki Tobari, Yoshitaka Iwaji, Junnosuke Nakatsugawa, Rikio Yoshikawa, Masamichi Yagai
  • Publication number: 20110241586
    Abstract: A sinusoidal signal is superimposed on a current command value of a q-axis (torque shaft) supplied from a host, and according to the resulting current command value, the output voltage of a power converter is controlled. For the calculation of the superimposed signal added to the current command value of the q-axis, with the use of the ripple component information of induced voltage coefficients of the d-axis and q-axis of the rotating coordinate system of a permanent magnet motor, the current command values of the d-axis and q-axis, an average value of induced voltage coefficients of the d-axis, and inductance values of the d-axis and q-axis, the sinusoidal superimposed signal is calculated and added to the above-described current command value of the q-axis.
    Type: Application
    Filed: February 17, 2011
    Publication date: October 6, 2011
    Inventors: Kazuaki TOBARI, Rikio Yoshikawa, Katsuhiro Mochizuki
  • Publication number: 20110175556
    Abstract: A torque ripple suppression control device for a permanent magnet motor includes a current command conversion unit that outputs a current command value, a position detector that detects a rotational position of the permanent magnet motor, a current detection unit that detects a current at the permanent magnet motor, an induced voltage coefficient setting unit that outputs an information signal related to an induced voltage coefficient for an induced voltage at the permanent magnet motor, a torque ripple suppression operation unit that outputs a current correction command value for the permanent magnet motor, a current control operation unit that outputs a voltage command value based upon addition results obtained by adding together the current command value and the current correction command value and the current detection value, and a power converter that outputs a voltage with which the permanent magnet motor is to be driven.
    Type: Application
    Filed: January 19, 2011
    Publication date: July 21, 2011
    Inventors: Kazuaki TOBARI, Yoshitaka Iwaji, Junnosuke Nakatsugawa, Rikio Yoshikawa, Masamichi Yagai
  • Patent number: 6703738
    Abstract: An outer rotor type brushless motor comprising an outer rotor having permanent magnets fixed onto an inner periphery of a rotor yoke, a stator including a stator core having a plural of magnetic pole portions protruded on an outer periphery thereof and coils wound on the magnetic pole portions, a cylindrical boss disposed on an inner periphery of an annular portion of the stator core, a rotational shaft extending along an axis of the boss and rotationally supported on the boss through a bearing with a leading end of the shaft having a center portion of the rotor yoke fixed thereto and a mounting plate fixed onto an outer periphery of the boss wherein the boss is formed of resin mold and extending through a hole in the mounting plate and fixed thereto and the annular portion of the stator core is mounted on and fixed to a rising portion on the inner periphery of the mounting plate.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: March 9, 2004
    Assignee: Kokusan Denki Co., Ltd.
    Inventors: Rikio Yoshikawa, Katsuhiro Mochizuki
  • Publication number: 20020063494
    Abstract: An outer rotor type brushless motor comprising an outer rotor having permanent magnets fixed onto an inner periphery of a rotor yoke, a stator including a stator core having a plural of magnetic pole portions protruded on an outer periphery thereof and coils wound on the magnetic pole portions, a cylindrical boss disposed on an inner periphery of an annular portion of the stator core, a rotational shaft extending along an axis of the boss and rotationally supported on the boss through a bearing with a leading end of the shaft having a center portion of the rotor yoke fixed thereto and a mounting plate fixed onto an outer periphery of the boss wherein the boss is formed of resin mold and extending through a hole in the mounting plate and fixed thereto and the annular portion of the stator core is mounted on and fixed to a rising portion on the inner periphery of the mounting plate.
    Type: Application
    Filed: November 21, 2001
    Publication date: May 30, 2002
    Inventors: Rikio Yoshikawa, Katsuhiro Mochizuki
  • Patent number: 5493188
    Abstract: A control device for a brushless motor capable of stopping the brushless motor without any complicated control. The control device includes a rotation control section to which an output of a position detector detecting a polarity of a magnet field of a rotor on a side of a stator is fed and which generates a driving signal of a predetermined polarity based on the output of the position detector input thereto. Also it includes a motor driving section to which the driving signal is fed and which flows an excitation current through a driving coil for a phase determined depending on a polarity of the driving signal input thereto.
    Type: Grant
    Filed: October 19, 1994
    Date of Patent: February 20, 1996
    Assignee: Kokusan Denki Co., Ltd.
    Inventors: Rikio Yoshikawa, Shuichi Kobayashi