Patents by Inventor Mitsuo Kashima

Mitsuo Kashima 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).

  • Publication number: 20220294377
    Abstract: An estimation device includes a phase current determination unit, a time difference calculation unit, and an estimation unit. The phase current determination unit performs a determination process for determining values of phase currents based on the value of the bus current detected by a bus current detection unit and states of gate pulse signals. The time difference calculation unit calculates a difference between a detection time of the bus current used in a previous determination process and a detection time of the bus current used in a present determination process. The estimation unit estimates at least one of a position and a speed of an AC motor based on the values of the phase currents determined by the phase current determination unit and the difference calculated by the time difference calculation unit.
    Type: Application
    Filed: August 23, 2019
    Publication date: September 15, 2022
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kenji TAKAHASHI, Shinya TOYODOME, Mitsuo KASHIMA, Tomohiro KUTSUKI
  • Patent number: 11437930
    Abstract: It provides an inverter main circuit converting a DC-voltage into three-phase AC-voltages, a DC-current detection unit detecting the DC-current value of a DC-current flowing in the main circuit, and an inverter control unit generating a drive signal for controlling operation of the main circuit using a voltage command value corresponding to each phase of the three-phase AC-voltages and a triangular-wave carrier. Using a time period during which the triangular-wave carrier monotonically increases or decreases as a unit period, the control unit provides control to alternately use, as the DC-current value for use in computation of the voltage command value, the DC-current value detected in the unit period in which the triangular-wave carrier monotonically increases and the DC-current value detected in the unit period in which the triangular-wave carrier monotonically decreases, for every voltage command value control period set to three times or more and an integer multiple of the unit period.
    Type: Grant
    Filed: September 21, 2018
    Date of Patent: September 6, 2022
    Assignee: Mitsubishi Electric Corporation
    Inventors: Shigeya Okada, Mitsuo Kashima
  • Publication number: 20220200498
    Abstract: A motor drive device: a power conversion unit; a current detection unit that detects a phase current of the alternating-current motor; a position/speed specifying unit that specifies a magnetic pole position and a rotational speed of the alternating-current motor; a d-axis current pulsation generating unit that generates a d-axis current pulsation command based on q-axis current pulsation or a q-axis current pulsation command, which being in synchronization with the q-axis current pulsation or the q-axis current pulsation command and preventing or reducing an increase or decrease in amplitude of the voltage command; and a dq-axis current control unit that generates the voltage command for controlling the phase current on the dq rotating coordinates, which rotate in synchronization with the magnetic pole position, by using the magnetic pole position, the rotational speed, the phase current, the q-axis current pulsation or the q-axis current pulsation command, and the d-axis current pulsation command.
    Type: Application
    Filed: May 20, 2019
    Publication date: June 23, 2022
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kenji TAKAHASHI, Shinya TOYODOME, Mitsuo KASHIMA, Tomohiro KUTSUKI
  • Publication number: 20220149764
    Abstract: A speed estimating device for an AC motor includes: a model deviation computing unit computing a model deviation based on a voltage, a current, and an estimated angular velocity of the AC motor; a first angular velocity estimating unit computing a first estimated angular velocity based on the model deviation; a second angular velocity estimating unit computing a second estimated angular velocity differing from the first estimated angular velocity in frequency, based on the model deviation; a compensation phase computing unit computing a compensation phase based on a disturbance frequency; and an estimated angular velocity calculator computing an estimated angular velocity of the AC motor based on the first estimated angular velocity and the second estimated angular velocity. Either one of the first estimated angular velocity and the second estimated angular velocity is computed based on the compensation phase.
    Type: Application
    Filed: March 22, 2019
    Publication date: May 12, 2022
    Applicant: Mitsubishi Electric Corporation
    Inventors: Yuriko TAKEDA, Kenji TAKAHASHI, Shinya TOYODOME, Mitsuo KASHIMA, Tomohiro KUTSUKI
  • Patent number: 11098928
    Abstract: A speed estimation apparatus for an AC motor includes a model deviation calculation unit, first and second angular velocity estimation units, and an adder. The deviation calculation unit calculates a model deviation based on a voltage, a current, and an estimated angular velocity of the motor. The first angular velocity estimation unit calculates a first estimated angular velocity as a low-frequency component including a DC component of a real angular velocity based on the model deviation. The second angular velocity estimation unit calculates a second estimated angular velocity as a high-frequency component of a real angular velocity based on a specific high-frequency component of the model deviation. The adder adds the first and second estimated angular velocities together. An addition value of the first and second estimated angular velocities is fed back as the estimated angular velocity to the deviation calculation unit.
    Type: Grant
    Filed: April 18, 2017
    Date of Patent: August 24, 2021
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kenji Takahashi, Koichi Arisawa, Mitsuo Kashima
  • Publication number: 20210242800
    Abstract: It provides an inverter main circuit converting a DC-voltage into three-phase AC-voltages, a DC-current detection unit detecting the DC-current value of a DC-current flowing in the main circuit, and an inverter control unit generating a drive signal for controlling operation of the main circuit using a voltage command value corresponding to each phase of the three-phase AC-voltages and a triangular-wave carrier. Using a time period during which the triangular-wave carrier monotonically increases or decreases as a unit period, the control unit provides control to alternately use, as the DC-current value for use in computation of the voltage command value, the DC-current value detected in the unit period in which the triangular-wave carrier monotonically increases and the DC-current value detected in the unit period in which the triangular-wave carrier monotonically decreases, for every voltage command value control period set to three times or more and an integer multiple of the unit period.
    Type: Application
    Filed: September 21, 2018
    Publication date: August 5, 2021
    Inventors: Shigeya OKADA, Mitsuo KASHIMA
  • Patent number: 11070157
    Abstract: An electric motor drive unit includes a winding switching unit that switches a configuration of windings of an electric motor, a winding switching instruction unit that generates an instruction signal for the winding switching unit, and a winding configuration retention unit to which the instruction signal generated by the winding switching instruction unit is input, and if the input instruction signal has a first value, outputs a signal corresponding to the input instruction signal to the winding switching unit, and if the input instruction signal has a second value different from the first value, continues outputting a signal that has been output to the winding switching unit before the reception of the second value, the first value indicating an instruction on the configuration of the windings.
    Type: Grant
    Filed: July 21, 2017
    Date of Patent: July 20, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Mitsuo Kashima, Keiichiro Shizu, Kazunori Hatakeyama
  • Patent number: 11031896
    Abstract: An electric quantity of a power supply of a connection switching device for switching the connection state of a motor, or at least one electric quantity which varies with the first-mentioned electric quantity is detected, the result of the detection is used to detect or predict a fall of a voltage of the switching power supply. Based on the result of the detection or prediction, an inverter is so controlled as to stop the motor before the voltage of the switching power supply falls below the minimum voltage required for the operation of the connection switching device. Breakdown of the connection switching device can be prevented.
    Type: Grant
    Filed: July 31, 2017
    Date of Patent: June 8, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kazunori Hatakeyama, Keiichiro Shizu, Mitsuo Kashima
  • Publication number: 20200403547
    Abstract: An electric quantity of a power supply of a connection switching device for switching the connection state of a motor, or at least one electric quantity which varies with the first-mentioned electric quantity is detected, the result of the detection is used to detect or predict a fall of a voltage of the switching power supply. Based on the result of the detection or prediction, an inverter is so controlled as to stop the motor before the voltage of the switching power supply falls below the minimum voltage required for the operation of the connection switching device. Breakdown of the connection switching device can be prevented.
    Type: Application
    Filed: July 31, 2017
    Publication date: December 24, 2020
    Inventors: Kazunori HATAKEYAMA, Keiichiro SHIZU, Mitsuo KASHIMA
  • Publication number: 20200321900
    Abstract: An electric motor drive unit includes a winding switching unit that switches a configuration of windings of an electric motor, a winding switching instruction unit that generates an instruction signal for the winding switching unit, and a winding configuration retention unit to which the instruction signal generated by the winding switching instruction unit is input, and if the input instruction signal has a first value, outputs a signal corresponding to the input instruction signal to the winding switching unit, and if the input instruction signal has a second value different from the first value, continues outputting a signal that has been output to the winding switching unit before the reception of the second value, the first value indicating an instruction on the configuration of the windings.
    Type: Application
    Filed: July 21, 2017
    Publication date: October 8, 2020
    Inventors: Mitsuo KASHIMA, Keiichiro SHIZU, Kazunori HATAKEYAMA
  • Patent number: 10696141
    Abstract: A synchronous motor control device includes: a DC power supply; an inverter main circuit; a three-phase synchronous motor; and an inverter control unit that outputs a PWM signal used to control the inverter main circuit. The inverter control unit includes: a PWM signal generation unit; a start-up control unit that outputs a start-up voltage command value to the PWM signal generation unit at the time of start-up; a steady state control unit that calculates a steady state voltage command value in a steady state and outputs the value to the PWM signal generation unit; and a steady state control parameter initial value calculation unit that outputs an initial value of a control parameter to the steady state control unit such that an output voltage vector from the inverter main circuit to the three-phase synchronous motor is consistent before and after switching from the start-up to the steady state.
    Type: Grant
    Filed: August 4, 2015
    Date of Patent: June 30, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Mitsuo Kashima, Tomohiro Kutsuki, Tomomi Higashikawa, Akiyoshi Muramatsu
  • Patent number: 10690370
    Abstract: The present invention includes a plurality of fan motors, first and second inverters for individually driving the fan motors, respectively, and one and a common control unit that performs a control arithmetic for each of the fan motors and generates an individual driving signal given to each of the inverters.
    Type: Grant
    Filed: September 26, 2014
    Date of Patent: June 23, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Keisuke Uemura, Kazunori Hatakeyama, Yosuke Shinomoto, Mitsuo Kashima, Takashi Matsumoto
  • Patent number: 10476423
    Abstract: A synchronous motor control device includes a voltage detector, a current detector, an inverter main circuit, and an inverter control unit. The inverter control unit includes: a phase current reproduction unit that reproduces a direct current into phase currents flowing to a permanent magnet synchronous motor; a current coordinate transformation unit that transforms the reproduced phase current into current on a control coordinate axis of a rotating coordinate system; a current control unit that calculates a voltage command value of the permanent magnet synchronous motor in such a manner that the current on the control coordinate axis equals a specific value; and a limiter unit that limits the value of the voltage command value.
    Type: Grant
    Filed: August 4, 2015
    Date of Patent: November 12, 2019
    Assignee: Mitsubishi Electric Corporation
    Inventors: Mitsuo Kashima, Tomohiro Kutsuki, Tomomi Higashikawa, Akiyoshi Muramatsu
  • Publication number: 20190334456
    Abstract: There are included an inverter main circuit which converts DC power into three-phase AC power by using a plurality of semiconductor switching elements, a DC current detection circuit which detects a current flowing through the DC bus bar, and an inverter control unit which outputs PWM drive signals for controlling the inverter main circuit based on a detected DC current. A wide band gap semiconductor element is used as each of the semiconductor switching elements, and a parasitic diode of the wide band gap semiconductor element is used as a reflux diode. When it is defined that a short-circuit prevention time for preventing short-circuit between the upper arm switching element and the lower arm switching element be td, a semiconductor switching element is set in which a reverse recovery time trr of the parasitic diode has characteristics of (td/100)?trr?(td/10).
    Type: Application
    Filed: September 2, 2016
    Publication date: October 31, 2019
    Inventor: Mitsuo KASHIMA
  • Publication number: 20190145668
    Abstract: A speed estimation apparatus for an AC motor includes a model deviation calculation unit, first and second angular velocity estimation units, and an adder. The deviation calculation unit calculates a model deviation based on a voltage, a current, and an estimated angular velocity of the motor. The first angular velocity estimation unit calculates a first estimated angular velocity as a low-frequency component including a DC component of a real angular velocity based on the model deviation. The second angular velocity estimation unit calculates a second estimated angular velocity as a high-frequency component of a real angular velocity based on a specific high-frequency component of the model deviation. The adder adds the first and second estimated angular velocities together. An addition value of the first and second estimated angular velocities is fed back as the estimated angular velocity to the deviation calculation unit.
    Type: Application
    Filed: April 18, 2017
    Publication date: May 16, 2019
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kenji TAKAHASHI, Koichi ARISAWA, Mitsuo KASHIMA
  • Publication number: 20180208023
    Abstract: A synchronous motor control device includes: a DC power supply; an inverter main circuit; a three-phase synchronous motor; and an inverter control unit that outputs a PWM signal used to control the inverter main circuit. The inverter control unit includes: a PWM signal generation unit; a start-up control unit that outputs a start-up voltage command value to the PWM signal generation unit at the time of start-up; a steady state control unit that calculates a steady state voltage command value in a steady state and outputs the value to the PWM signal generation unit; and a steady state control parameter initial value calculation unit that outputs an initial value of a control parameter to the steady state control unit such that an output voltage vector from the inverter main circuit to the three-phase synchronous motor is consistent before and after switching from the start-up to the steady state.
    Type: Application
    Filed: August 4, 2015
    Publication date: July 26, 2018
    Inventors: Mitsuo KASHIMA, Tomohiro KUTSUKI, Tomomi HIGASHIKAWA, Akiyoshi MURAMATSU
  • Patent number: 9998049
    Abstract: An inverter control device includes an inverter main circuit, a current detector, a voltage detector that detects a DC voltage between DC bus lines, and an inverter control unit that generates PWM signals to perform on/off control of a plurality of semiconductor switching elements respectively with a DC current and a DC voltage. The unit sets a carrier period of PWM signals to be 1/N times a calculation period in which the PWM signals are generated, performs detection of a DC current detected by the current detector in a 1/2 calculation period immediately before a calculation start timing for generating PWM signals, calculates an output voltage vector based on the detected DC current, and reflects PWM signals generated from the output voltage vector in one calculation period from a 1/2 calculation period after the calculation start timing to 3/2 control calculation periods after the same.
    Type: Grant
    Filed: August 4, 2015
    Date of Patent: June 12, 2018
    Assignee: Mitsubishi Electric Corporation
    Inventors: Mitsuo Kashima, Shigeo Umehara
  • Publication number: 20180131308
    Abstract: A synchronous motor control device includes a voltage detector, a current detector, an inverter main circuit, and an inverter control unit. The inverter control unit includes: a phase current reproduction unit that reproduces a direct current into phase currents flowing to a permanent magnet synchronous motor; a current coordinate transformation unit that transforms the reproduced phase current into current on a control coordinate axis of a rotating coordinate system; a current control unit that calculates a voltage command value of the permanent magnet synchronous motor in such a manner that the current on the control coordinate axis equals a specific value; and a limiter unit that limits the value of the voltage command value.
    Type: Application
    Filed: August 4, 2015
    Publication date: May 10, 2018
    Inventors: Mitsuo KASHIMA, Tomohiro KUTSUKI, Tomomi HIGASHIKAWA, Akiyoshi MURAMATSU
  • Publication number: 20180091079
    Abstract: An inverter control device includes an inverter main circuit, a current detector, a voltage detector that detects a DC voltage between DC bus lines, and an inverter control unit that generates PWM signals to perform on/off control of a plurality of semiconductor switching elements respectively with a DC current and a DC voltage. The unit sets a carrier period of PWM signals to be 1/N times a calculation period in which the PWM signals are generated, performs detection of a DC current detected by the current detector in a 1/2 calculation period immediately before a calculation start timing for generating PWM signals, calculates an output voltage vector based on the detected DC current, and reflects PWM signals generated from the output voltage vector in one calculation period from a 1/2 calculation period after the calculation start timing to 3/2 control calculation periods after the same.
    Type: Application
    Filed: August 4, 2015
    Publication date: March 29, 2018
    Inventors: Mitsuo KASHIMA, Shigeo UMEHARA
  • Patent number: 9929670
    Abstract: A power conversion device is configured to have reactors and is configured to have chopper circuit units, connected in series, that chop the output of a rectifier configured to rectify an AC voltage from an AC power supply. The power conversion device includes: an AC switch disposed on a side closer to the AC power supply than the chopper circuit units; an AC reactor that is connected in parallel to the AC switch; and a switching control unit that stops the switching of the switching elements when the contact of the AC switch is open.
    Type: Grant
    Filed: May 26, 2014
    Date of Patent: March 27, 2018
    Assignee: Mitsubishi Electric Corporation
    Inventors: Michio Yamada, Takuya Shimomugi, Yosuke Shinomoto, Mitsuo Kashima, Shigeo Umehara