Patents by Inventor Nobuki Kitano

Nobuki Kitano 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: 11218107
    Abstract: A power converter converts a DC voltage including a pulsation component into an AC voltage and outputs the AC voltage to a synchronous electrical motor. A control device for controlling the power converter includes a pulsation component detection unit and a control circuit. The pulsation component detection unit detects a pulsation component. The control circuit controls the power converter so that a load angle of the synchronous electrical motor is increased in accordance with increase in an instantaneous value of the pulsation component.
    Type: Grant
    Filed: August 24, 2017
    Date of Patent: January 4, 2022
    Assignee: DAIKIN INDUSTRIES, LTD.
    Inventors: Ryuuji Yasumoto, Nobuki Kitano, Naoto Kobayashi, Minoru Kitou
  • Patent number: 10651757
    Abstract: An inverter device includes a converter section, an inverter section, and a control device. The converter section full-wave rectifies a three-phase AC voltage and outputs a DC voltage including a ripple component having a frequency six times the frequency of the three-phase AC voltage. The inverter section converts the DC voltage including the ripple component from the converter section into an AC voltage and outputs the AC voltage to a motor. The control device, in a rotating coordinate in which an N-pole direction of a permanent magnet embedded in a rotor of the motor is taken as a d-axis and a direction orthogonal to the d-axis is taken as a q-axis, controls the inverter section so that a phase of a d-axis voltage Vd of the ripple component included in the DC voltage leads a phase of a q-axis voltage Vq.
    Type: Grant
    Filed: June 20, 2017
    Date of Patent: May 12, 2020
    Assignee: Daikin Industries, Ltd.
    Inventors: Nobuki Kitano, Tatsuki Inoue
  • Patent number: 10615704
    Abstract: An inverter device includes a converter section, an inverter section, and a control device. The converter section full-wave rectifies a three-phase AC voltage and outputs a DC voltage including a ripple component having a frequency six times the frequency of the three-phase AC voltage. The inverter section converts the DC voltage including the ripple component from the converter section into an AC voltage and outputs the AC voltage to a motor. The control device, in a rotating coordinate in which an N-pole direction of a permanent magnet embedded in a rotor of the motor is taken as a d-axis and a direction orthogonal to the d-axis is taken as a q-axis, controls the inverter section so that a phase of a d-axis voltage Vd of the ripple component included in the DC voltage leads a phase of a q-axis voltage Vq.
    Type: Grant
    Filed: June 20, 2017
    Date of Patent: April 7, 2020
    Assignee: Daikin Industries, Ltd.
    Inventors: Nobuki Kitano, Tatsuki Inoue
  • Publication number: 20200036316
    Abstract: A power converter converts a DC voltage including a pulsation component into an AC voltage and outputs the AC voltage to a synchronous electrical motor. A control device for controlling the power converter includes a pulsation component detection unit and a control circuit. The pulsation component detection unit detects a pulsation component. The control circuit controls the power converter so that a load angle of the synchronous electrical motor is increased in accordance with increase in an instantaneous value of the pulsation component.
    Type: Application
    Filed: August 24, 2017
    Publication date: January 30, 2020
    Applicant: DAIKIN INDUSTRIES, LTD.
    Inventors: Ryuuji YASUMOTO, Nobuki KITANO, Naoto KOBAYASHI, Minoru KITOU
  • Publication number: 20200007049
    Abstract: An inverter device includes a converter section, an inverter section, and a control device. The converter section full-wave rectifies a three-phase AC voltage and outputs a DC voltage including a ripple component having a frequency six times the frequency of the three-phase AC voltage. The inverter section converts the DC voltage including the ripple component from the converter section into an AC voltage and outputs the AC voltage to a motor. The control device, in a rotating coordinate in which an N-pole direction of a permanent magnet embedded in a rotor of the motor is taken as a d-axis and a direction orthogonal to the d-axis is taken as a q-axis, controls the inverter section so that a phase of a d-axis voltage Vd of the ripple component included in the DC voltage leads a phase of a q-axis voltage Vq.
    Type: Application
    Filed: June 20, 2017
    Publication date: January 2, 2020
    Inventors: Nobuki KITANO, Tatsuki INOUE
  • Patent number: 10305405
    Abstract: A subtractor subtracts an angular speed correction amount from a rotational speed command to obtain a corrected rotational speed command. An adder adds a second-axis current correction value to a ?c-axis current to obtain a corrected second-axis current. An angular ripple extraction unit obtains, from a rotational angle on a mechanical angle of a synchronous motor, a rotational angle difference being a ripple component of the rotational angle. An nth-order component extraction unit extracts nth-order components of a fundamental frequency of the rotational angle from the rotational angle difference. A torque conversion unit obtains nth-order components of an estimated value of vibration torque. A correction amount calculation unit obtains the second-axis current correction value using the nth-order components.
    Type: Grant
    Filed: October 27, 2016
    Date of Patent: May 28, 2019
    Assignee: DAIKIN INDUSTRIES, LTD.
    Inventors: Minoru Kitou, Nobuki Kitano, Naoto Kobayashi, Hiroshi Hibino, Ryou Matsuyama
  • Patent number: 10298158
    Abstract: A feedback amount calculation unit uses a deviation of a current from its command value or a deviation of an air-gap flux from its command value to calculate a feedback amount. A voltage error calculation unit calculates a variation range of a voltage error between a voltage value based on a voltage equation of the electric motor and a voltage command. The presence or absence of step-out of the electric motor is determined by comparison between the variation range of the voltage error and the feedback amount.
    Type: Grant
    Filed: January 6, 2015
    Date of Patent: May 21, 2019
    Assignee: Daikin Industries, Ltd.
    Inventors: Hiroshi Hibino, Nobuki Kitano
  • Publication number: 20180309398
    Abstract: A subtractor subtracts an angular speed correction amount from a rotational speed command to obtain a corrected rotational speed command. An adder adds a second-axis current correction value to a ?c-axis current to obtain a corrected second-axis current. An angular ripple extraction unit obtains, from a rotational angle on a mechanical angle of a synchronous motor, a rotational angle difference being a ripple component of the rotational angle. An nth-order component extraction unit extracts nth-order components of a fundamental frequency of the rotational angle from the rotational angle difference. A torque conversion unit obtains nth-order components of an estimated value of vibration torque. A correction amount calculation unit obtains the second-axis current correction value using the nth-order components.
    Type: Application
    Filed: October 27, 2016
    Publication date: October 25, 2018
    Applicant: DAIKIN INDUSTRIES, LTD.
    Inventors: Minoru KITOU, Nobuki KITANO, Naoto KOBAYASHI, Hiroshi HIBINO, Ryou MATSUYAMA
  • Patent number: 10110150
    Abstract: A primary magnetic flux command value is changed in accordance with a torque of a rotary electric motor to control a current phase of an armature current with respect to a q axis that advances by ?/2 with respect to a d axis in phase with a field flux to be a desired phase in accordance with the torque.
    Type: Grant
    Filed: October 8, 2013
    Date of Patent: October 23, 2018
    Assignee: DAIKIN INDUSTRIES, LTD.
    Inventors: Takeshi Araki, Naoto Kobayashi, Nobuki Kitano
  • Patent number: 9634580
    Abstract: A difference command generator generates a difference command equivalent to a time integral of three-phase voltage applied to an inductive load in a predetermined cycle in a complex plane. A vector command generator generates vector commands that are respectively time integrals of voltage vectors and compose the difference command. A switching signal generator generates switching signals for controlling three pairs of switches in an inverter on the basis of the vector commands. A phase-current computing unit obtains an estimated value for the three-phase current on the basis of a current flowing DC buses and the vector commands. At least two of the vector commands that are time integrals of different ones of the non-zero voltage vectors have magnitudes greater than or equal to a predetermined value corresponding to a minimum required amount of time to maintain switching patterns in order for the phase-current computing unit to detect the current.
    Type: Grant
    Filed: March 4, 2014
    Date of Patent: April 25, 2017
    Assignee: DAIKIN INDUSTRIES, LTD.
    Inventors: Michihiro Nakagawa, Nobuki Kitano, Naoto Kobayashi
  • Publication number: 20170005603
    Abstract: A feedback amount calculation unit uses a deviation of a current from its command value or a deviation of an air-gap flux from its command value to calculate a feedback amount. A voltage error calculation unit calculates a variation range of a voltage error between a voltage value based on a voltage equation of the electric motor and a voltage command. The presence or absence of step-out of the electric motor is determined by comparison between the variation range of the voltage error and the feedback amount.
    Type: Application
    Filed: January 6, 2015
    Publication date: January 5, 2017
    Applicant: DAIKIN INDUSTRIES, LTD.
    Inventors: Hiroshi HIBINO, Nobuki KITANO
  • Patent number: 9479100
    Abstract: An electric motor controller includes a first coordinate conversion unit that converts a three-phase current into a current in a ?c-?c rotating coordinate system, a first calculation unit that obtains a first term, a second calculation unit that obtains a voltage command value in the ?c-?c rotating coordinate system as a sum of the first term and a second term, a second coordinate conversion unit that coordinate-converts the voltage command value into a voltage command value of a voltage to be applied to a rotary electric motor in another coordinate system.
    Type: Grant
    Filed: July 11, 2013
    Date of Patent: October 25, 2016
    Assignee: DAIKIN INDUSTRIES, LTD.
    Inventors: Takeshi Araki, Naoto Kobayashi, Nobuki Kitano
  • Publication number: 20160020708
    Abstract: A difference command generator generates a difference command equivalent to a time integral of three-phase voltage applied to an inductive load in a predetermined cycle in a complex plane. A vector command generator generates vector commands that are respectively time integrals of voltage vectors and compose the difference command. A switching signal generator generates switching signals for controlling three pairs of switches in an inverter on the basis of the vector commands. A phase-current computing unit obtains an estimated value for the three-phase current on the basis of a current flowing DC buses and the vector commands. At least two of the vector commands that are time integrals of different ones of the non-zero voltage vectors have magnitudes greater than or equal to a predetermined value corresponding to a minimum required amount of time to maintain switching patterns in order for the phase-current computing unit to detect the current.
    Type: Application
    Filed: March 4, 2014
    Publication date: January 21, 2016
    Applicant: DAIKIN INDUSTRIES, LTD.
    Inventors: Michihiro NAKAGAWA, Nobuki KITANO, Naoto KOBAYASHI
  • Publication number: 20150311846
    Abstract: A primary magnetic flux command value is changed in accordance with a torque of a rotary electric motor to control a current phase of an armature current with respect to a q axis that advances by ?/2 with respect to a d axis in phase with a field flux to be a desired phase in accordance with the torque.
    Type: Application
    Filed: October 8, 2013
    Publication date: October 29, 2015
    Applicant: DAIKIN INDUSTRIES, LTD.
    Inventors: Takeshi ARAKI, Naoto KOBAYASHI, Nobuki KITANO
  • Publication number: 20150229258
    Abstract: An electric motor controller includes a first coordinate conversion unit that converts a three-phase current into a current in a ?c-?c rotating coordinate system, a first calculation unit that obtains a first term, a second calculation unit that obtains a voltage command value in the ?c-?c rotating coordinate system as a sum of the first term and a second term, a second coordinate conversion unit that coordinate-converts the voltage command value into a voltage command value of a voltage to be applied to a rotary electric motor in another coordinate system.
    Type: Application
    Filed: July 11, 2013
    Publication date: August 13, 2015
    Applicant: DAIKIN INDUSTRIES, LTD.
    Inventors: Takeshi Araki, Naoto Kobayashi, Nobuki Kitano
  • Patent number: 9018871
    Abstract: A carrier generating unit applies a carrier that monotonically decreases to a switching control unit during either one of a first period that is a period immediately following a period in which a voltage command value is a value not more than a minimum value of the carrier, the voltage command value taking a first predetermined value larger than the minimum value of the carrier in the first period, and a second period that is a period immediately preceding a period in which the voltage command value is not less than a maximum value of the carrier, the voltage command value taking a second predetermined value smaller than the maximum value in the second period.
    Type: Grant
    Filed: October 26, 2011
    Date of Patent: April 28, 2015
    Assignee: Daikin Industries, Ltd.
    Inventors: Takeshi Ashida, Hiroshi Hibino, Naoto Kobayashi, Michihiro Nakagawa, Nobuki Kitano, Masaki Kouno
  • Publication number: 20130221884
    Abstract: A carrier generating unit applies a carrier that monotonically decreases to a switching control unit during either one of a first period that is a period immediately following a period in which a voltage command value is a value not more than a minimum value of the carrier, the voltage command value taking a first predetermined value larger than the minimum value of the carrier in the first period, and a second period that is a period immediately preceding a period in which the voltage command value is not less than a maximum value of the carrier, the voltage command value taking a second predetermined value smaller than the maximum value in the second period.
    Type: Application
    Filed: October 26, 2011
    Publication date: August 29, 2013
    Applicant: DAIKIN INDUSTRIES, LTD.
    Inventors: Takeshi Ashida, Hiroshi Hibino, Naoto Kobayashi, Michihiro Nakagawa, Nobuki Kitano, Masaki Kouno
  • Patent number: 8182245
    Abstract: A boot capacitor that functions as an operating power supply for a high-arm-side transistor provided in an inverter has to be charged prior to normal operation of a motor. This operation of charging the boot capacitor is performed at a carrier frequency that is lower than a carrier frequency for the normal operation.
    Type: Grant
    Filed: January 7, 2008
    Date of Patent: May 22, 2012
    Assignee: Daikin Industries, Ltd.
    Inventors: Hirohito Maeda, Keisuke Shimatani, Masakazu Katou, Takeomi Ukai, Hironobu Mizobe, Nobuki Kitano
  • Publication number: 20100232983
    Abstract: A boot capacitor that functions as an operating power supply for a high-arm-side transistor provided in an inverter has to be charged prior to normal operation of a motor. This operation of charging the boot capacitor is performed at a carrier frequency that is lower than a carrier frequency for the normal operation.
    Type: Application
    Filed: January 7, 2008
    Publication date: September 16, 2010
    Inventors: Hirohito Maeda, Keisuke Shimatani, Masakazu Katou, Takeomi Ukai, Hironobu Mizobe, Nobuki Kitano
  • Patent number: 7579800
    Abstract: A motor control apparatus comprises the amplitude adjustment section and the peak voltage control section so as to adjust the torque control output in correspondence with the output voltage of the inverter. The peak voltage control section detects the peak voltage of the voltage command, and outputs the adjustment command instructing the amplitude adjustment section to suppress the amplitude when the peak voltage possibly exceed the previously determined value which is determined with respect to the maximum output voltage or maximum modulation rate of the inverter. The amplitude adjustment section lowers the gain by carrying out processing such that a constant proportional value is removed from the integration value, for example, in response to the supplying of the adjustment command.
    Type: Grant
    Filed: October 10, 2003
    Date of Patent: August 25, 2009
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Nobuki Kitano