Patents by Inventor Takafumi Hara

Takafumi Hara 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: 12199539
    Abstract: An object of the present invention is to sufficiently suppress a vibration and noise generated in a motor. A motor control device includes a first inverter circuit and a second inverter circuit of a redundant system, the first inverter circuit and the second inverter circuit controlling a motor, and a control unit that controls the first inverter circuit and the second inverter circuit. The first inverter circuit converts the DC power into the AC power based on a PWM signal generated by using a first carrier signal. The second inverter circuit converts the DC power into the AC power based on a PWM signal generated by using a second carrier signal. The control unit shifts phases of the first carrier signal and the second carrier signal by using, as a reference, pulsation of an electromagnetic force caused by a magnetic circuit of the motor.
    Type: Grant
    Filed: January 22, 2021
    Date of Patent: January 14, 2025
    Assignee: HITACHI ASTEMO, LTD.
    Inventors: Katsuhiro Hoshino, Takafumi Hara, Takaya Tsukagoshi
  • Patent number: 12170497
    Abstract: An inverter control device 200 includes a PWM control unit 220 that generates a PWM pulse for controlling an inverter 100, and a pulse edge control unit 250 that performs pulse edge control for correcting (shifting) a phase of a pulse edge of the PWM pulse generated by the PWM control unit 220. The PWM control unit 220 generates a PWM pulse by using a modulation rate based on a voltage command (Vd*, Vq*). The pulse edge control unit 250 corrects the PWM pulse so that a phase difference between a zero cross point where the modulation wave changes across 0 and a pulse edge of the PWM pulse falls within a predetermined range.
    Type: Grant
    Filed: January 22, 2021
    Date of Patent: December 17, 2024
    Assignee: Hitachi Astemo, Ltd.
    Inventors: Toshiyuki Ajima, Takafumi Hara, Akihiro Ashida, Hirokazu Matsui, Kiyoshi Kuroda
  • Patent number: 12162298
    Abstract: A manufacturing method of a printed material that stores machine-readable information, includes forming, on a base material, a first layer including a first code symbol that is machine-readable and represents first information, using a first coloring material, and forming, on the first layer, a second layer including a second code symbol that is machine-readable and represents second information, using a second coloring material that is different from the first coloring material and decolorable at a particular temperature, such that the first code symbol is at least partly covered by the second coloring material.
    Type: Grant
    Filed: January 20, 2023
    Date of Patent: December 10, 2024
    Assignee: Toshiba Tec Kabushiki Kaisha
    Inventors: Takafumi Hara, Maiko Miyoshi, Mamoru Nomura
  • Patent number: 12149183
    Abstract: A deviation between a detection result of an output current of an inverter and an actual current is suppressed. A current detection unit 7 detects a three-phase AC current output from an inverter 3 or input to the inverter 3. An inverter control device 1 controls the inverter 3 based on a current detection value based on a detection result of the three-phase AC current by the current detection unit 7 and a predetermined current command value. The inverter control device 1 corrects the current detection value so as to correct a detection error of the three-phase AC current generated due to a delay time of a filter 72 which is a filter element provided in the current detection unit 7.
    Type: Grant
    Filed: December 8, 2020
    Date of Patent: November 19, 2024
    Assignee: HITACHI ASTEMO, LTD.
    Inventors: Takafumi Hara, Toshiyuki Ajima, Akihiro Ashida, Kiyoshi Kuroda, Yoshinori Aoshima
  • Publication number: 20240380337
    Abstract: An inverter control device includes: a carrier wave generation unit that generates a carrier wave; a carrier frequency adjustment unit that adjusts a frequency of the carrier wave; and a PWM control unit that performs pulse width modulation on a voltage command using the carrier wave and generates a PWM pulse signal for controlling an operation of an inverter. The carrier frequency adjustment unit determines a phase shift amount for reducing a voltage amplitude of a specific order component among order components of a voltage ripple superimposed on a DC voltage, and adjusts a frequency of the carrier wave so as to change a phase difference between the voltage command and the carrier wave according to the determined phase shift amount.
    Type: Application
    Filed: March 4, 2022
    Publication date: November 14, 2024
    Inventors: Takafumi HARA, Takaya TSUKAGOSHI, Katsuhiro HOSHINO, Shigehisa AOYAGI
  • Publication number: 20240364233
    Abstract: An inverter control apparatus includes: a voltage command generating unit that generates a voltage command corresponding to each phase of AC power; a phase difference calculation unit that calculates a voltage difference between the phases of the voltage command; a required phase difference calculation unit that calculates a required phase difference representing a difference of voltages between the phases of the voltage command required to prevent semiconductor switching devices from turning on simultaneously in two phases; a voltage command correction unit that compares the calculated voltage difference and the calculated required phase difference calculated, and corrects the voltage command based on the comparison result; a carrier wave generating unit that generates a carrier wave; and a PWM signal generating unit that compares the voltage command that has been corrected by the voltage command correction unit with the carrier wave.
    Type: Application
    Filed: April 11, 2022
    Publication date: October 31, 2024
    Inventors: Hitoshi TANIGUCHI, Jia LI, Aya TOOYAMA, Takafumi HARA
  • Publication number: 20240291417
    Abstract: An inverter control device performs pulse width modulation by selecting one of a synchronous pulse control mode in which a frequency of a carrier wave used in the pulse width modulation is changed in accordance with a rotation speed of the motor and an asynchronous pulse control mode in which the frequency of the carrier wave is constant regardless of the rotation speed of the motor. At the time of switching from the asynchronous pulse control mode to the synchronous pulse control mode, the inverter control device changes a carrier reference phase that is a reference value of a phase of the carrier wave to a different value before and after the switching.
    Type: Application
    Filed: February 15, 2022
    Publication date: August 29, 2024
    Applicant: HITACHI ASTEMO, LTD.
    Inventors: Shigehisa AOYAGI, Takafumi HARA, Takaya TSUKAGOSHI
  • Patent number: 12074542
    Abstract: Conventionally, there is a problem that switching loss of an inverter increases in a case where a change such as improvement in a switching frequency is involved. The battery voltage E and the torque command T* are input to the first current command generation unit 111. The battery voltage E, the torque command T*, and a voltage utilization rate obtained by dividing a line voltage effective value by a battery voltage (DC voltage) are input to a second current command generation unit 112. A magnet temperature Tmag of a rotor magnet is input to a current command selection unit 113, and a current command output from the first current command generation unit 111 is selected in normal operation, and the second current command generation unit 112 is selected in a case where the magnet temperature exceeds a predetermined value. The second current command generation unit 112 is configured not to obtain the voltage utilization rate of 0.3 to 0.4.
    Type: Grant
    Filed: August 14, 2020
    Date of Patent: August 27, 2024
    Assignee: Hitachi Astemo, Ltd.
    Inventors: Takafumi Hara, Toshiyuki Ajima, Katsuhiro Hoshino, Noriyuki Maekawa
  • Patent number: 12074551
    Abstract: The present invention addresses the problem of properly performing motor control during overmodulation. In a motor control device 1, a carrier wave frequency adjusting unit 16 adjusts a carrier wave frequency fc so as to change a voltage phase error ??v representing the phase difference between three-phase voltage commands Vu*, Vv*, Vw* and a triangular wave signal Tr. When a modulation factor H in accordance with the voltage amplitude ratio between the DC power supplied from a high voltage battery to an inverter and AC power output from the inverter to a motor exceeds a predetermined value, for example, 1.15, a current control unit 14 corrects the amplitudes and phases of a d-axis voltage command Vd* and a q-axis voltage command Vq* on the basis of a carrier wave phase difference ??carr representing the phase of the triangular wave signal Tr.
    Type: Grant
    Filed: January 22, 2021
    Date of Patent: August 27, 2024
    Assignee: HITACHI ASTEMO, LTD.
    Inventors: Takafumi Hara, Toshiyuki Ajima, Takaya Tsukagoshi, Katsuhiro Hoshino
  • Publication number: 20240262413
    Abstract: A motor control device includes: an inverter circuit that drives a motor; and a control unit that generates a current command value on the basis of a torque command to the motor, and outputs a PWM pulse to the inverter circuit on the basis of the current command value to control the inverter circuit, and the control unit sets a phase shift amount of a carrier wave of the PWM pulse, estimates a fluctuating torque according to the phase shift amount, and corrects the current command value on the basis of the fluctuating torque.
    Type: Application
    Filed: February 15, 2022
    Publication date: August 8, 2024
    Applicant: HITACHI ASTEMO, LTD.
    Inventors: Katsuhiro HOSHINO, Takafumi HARA, Takaya TSUKAGOSHI
  • Publication number: 20240227771
    Abstract: A motor control device controls driving of an AC motor that is connected to a power transformer that performs power transform from DC power to AC power and outputs a rotational driving force generated by driving using the AC power via a speed reducer, and includes a carrier generator that generates a carrier wave, a carrier frequency adjuster that adjusts a frequency of the carrier wave, and a gate signal generator that performs pulse width modulation on a voltage command according to a torque command using the carrier wave and generates a gate signal for controlling an operation of the power transformer, wherein the carrier frequency adjuster changes a phase difference between the voltage command and the carrier wave based on the torque command and a rotational speed of the AC motor, and adjusts the frequency of the carrier wave such that a difference between a meshing frequency of the speed reducer and a harmonic component of a fundamental harmonic current according to the voltage command falls within a pre
    Type: Application
    Filed: February 9, 2022
    Publication date: July 11, 2024
    Applicant: HITACHI ASTEMO, LTD.
    Inventors: Takaya TSUKAGOSHI, Takafumi HARA, Katsuhiro HOSHINO, Shigehisa AOYAGI
  • Patent number: 11984821
    Abstract: An inverter control device 200 includes a current control unit 210 that outputs a voltage commands (Vd*, Vq*), a modulation wave control unit 220 that generates a modulation wave based on the voltage commands (Vd*, Vq*), a pulse generation unit 230 that generates a PWM pulse for controlling an inverter 100 using a modulation wave and a carrier wave of a predetermined frequency, and a pulse shift unit 250 that corrects the phase of the PWM pulse such that the PWM pulse is output in a phase corresponding to a harmonic of a predetermined order of the modulation wave in the near-zero-cross region including the zero-cross point at which the modulation wave changes across 0.
    Type: Grant
    Filed: July 31, 2020
    Date of Patent: May 14, 2024
    Assignee: Hitachi Astemo, Ltd.
    Inventors: Toshiyuki Ajima, Takafumi Hara, Akihiro Ashida, Hirokazu Matsui
  • Patent number: 11967915
    Abstract: The vibration and noise generated in a permanent magnet synchronous motor are effectively suppressed. A motor control device 1 comprises: a triangular wave generation unit 17 which generates a triangular wave signal Tr that is a carrier wave, a carrier frequency adjustment unit 16 which adjusts a carrier frequency fc that represents a frequency of the triangular wave signal Tr, and a gate signal generation unit 18 which performs pulse-width modulation on three-phase voltage commands Vu*, Vv*, Vw* according to a torque command T* using the triangular wave signal Tr, thereby generating a gate signal for controlling an operation of an inverter. The carrier frequency adjustment unit 16 adjusts the carrier frequency fc so as to change a voltage phase error ??v representing a phase difference of the three-phase voltage commands Vu*, Vv*, Vw* and the triangular wave signal Tr based on the torque command T*, and a rotation speed ?r of a motor.
    Type: Grant
    Filed: November 4, 2020
    Date of Patent: April 23, 2024
    Assignee: Hitachi Astemo, Ltd.
    Inventors: Takaya Tsukagoshi, Takafumi Hara, Katsuhiro Hoshino, Toshiyuki Ajima
  • Publication number: 20240042867
    Abstract: A motor control device connected to a power converter that performs power conversion from DC power to AC power and controls driving of an AC motor that is driven by using the AC power includes a voltage command generation unit that generates a three-phase voltage command; and a gate signal generation unit that performs pulse width modulation on the three-phase voltage command and generates a gate signal for controlling an operation of the power converter, in which the voltage command generation unit adjusts the three-phase voltage command by using a zero-phase voltage based on a power factor of the AC power in an overmodulation region in which a modulation factor according to a voltage amplitude ratio between the DC power and the AC power exceeds a predetermined threshold value, and the gate signal generation unit generates the gate signal by performing pulse width modulation on the adjusted three-phase voltage command.
    Type: Application
    Filed: September 29, 2021
    Publication date: February 8, 2024
    Inventors: Takafumi HARA, Toshiyuki AJIMA, Kyoshiro ITAKURA, Takeshi TOKUYAMA, Takahiro ARAKI, Shigehisa AOYAGI
  • Publication number: 20230402953
    Abstract: A motor control device is connected to a power converter that performs power conversion from DC power to AC power and controls driving of an AC motor driven using the AC power, and the motor control device includes a carrier wave generation unit that generates a carrier wave, a carrier wave frequency adjustment unit that adjusts a frequency of the carrier wave, and a gate signal generation unit that performs pulse width modulation on a voltage command according to a torque command using the carrier wave and generates a gate signal for controlling an operation of the power converter, in which a phase difference between the voltage command and the carrier wave is randomly changed.
    Type: Application
    Filed: September 21, 2021
    Publication date: December 14, 2023
    Applicant: HITACHI ASTEMO, LTD.
    Inventors: Takaya TSUKAGOSHI, Shun TANIGUCHI, Takafumi HARA
  • Patent number: 11831265
    Abstract: A motor control device includes a PWM control unit, a carrier frequency setting unit, and a carrier frequency switching calculation unit. The PWM unite generates a signal to drive an inverter by pulse width modulation. The carrier frequency setting unit sets a carrier frequency used for pulse width modulation according to a number of rotations of a motor. The carrier frequency switching calculation unit calculates a frequency switching speed of the carrier frequency and is configured to perform a calculation method. The calculation method includes setting at least one of an emergency mode, a response priority mode, or a fluctuation suppression priority mode in response to various operating conditions.
    Type: Grant
    Filed: November 14, 2019
    Date of Patent: November 28, 2023
    Assignee: Hitachi Astemo, Ltd.
    Inventors: Midori Takaoka, Takafumi Hara, Shigehisa Aoyagi, Hirokazu Matsui, Shigeyuki Nonomura
  • Publication number: 20230373228
    Abstract: A manufacturing method of a printed material that stores machine-readable information, includes forming, on a base material, a first layer including a first code symbol that is machine-readable and represents first information, using a first coloring material, and forming, on the first layer, a second layer including a second code symbol that is machine-readable and represents second information, using a second coloring material that is different from the first coloring material and decolorable at a particular temperature, such that the first code symbol is at least partly covered by the second coloring material.
    Type: Application
    Filed: January 20, 2023
    Publication date: November 23, 2023
    Inventors: Takafumi HARA, Maiko MIYOSHI, Mamoru NOMURA
  • Publication number: 20230223824
    Abstract: A motor control device of the present invention is connected to a power converter for converting power from direct current power to alternating current power, and controls the drive of an alternating current motor that is driven using said alternating current power, and the motor control device is provided with: a carrier wave generator; a carrier wave frequency adjuster that adjusts the frequency of the carrier wave; and a gate signal generator that uses the carrier wave to pulse width modulate a voltage command according to a torque command, and generates a gate signal for controlling operation of the power converter, wherein the carrier wave frequency adjuster adjusts the voltage command and carrier wave phase difference to reduce eddy current loss generated in rotor magnets of the alternating current motor according to a d-axis current flowing to the alternating current motor and the rotational speed of the alternating current motor.
    Type: Application
    Filed: March 1, 2021
    Publication date: July 13, 2023
    Applicant: Hitachi, Ltd.
    Inventors: Takafumi HARA, Makoto ITO, Akeshi TAKAHASHI, Toshiyuki AJIMA
  • Publication number: 20230155533
    Abstract: An object of the present invention is to sufficiently suppress a vibration and noise generated in a motor. A motor control device includes a first inverter circuit and a second inverter circuit of a redundant system, the first inverter circuit and the second inverter circuit controlling a motor, and a control unit that controls the first inverter circuit and the second inverter circuit. The first inverter circuit converts the DC power into the AC power based on a PWM signal generated by using a first carrier signal. The second inverter circuit converts the DC power into the AC power based on a PWM signal generated by using a second carrier signal. The control unit shifts phases of the first carrier signal and the second carrier signal by using, as a reference, pulsation of an electromagnetic force caused by a magnetic circuit of the motor.
    Type: Application
    Filed: January 22, 2021
    Publication date: May 18, 2023
    Applicant: Hitachi Astemo, Ltd.
    Inventors: Katsuhiro HOSHINO, Takafumi HARA, Takaya TSUKAGOSHI
  • Publication number: 20230155534
    Abstract: An inverter control device 200 includes a PWM control unit 220 that generates a PWM pulse for controlling an inverter 100, and a pulse edge control unit 250 that performs pulse edge control for correcting (shifting) a phase of a pulse edge of the PWM pulse generated by the PWM control unit 220. The PWM control unit 220 generates a PWM pulse by using a modulation rate based on a voltage command (Vd*, Vq*). The pulse edge control unit 250 corrects the PWM pulse so that a phase difference between a zero cross point where the modulation wave changes across 0 and a pulse edge of the PWM pulse falls within a predetermined range.
    Type: Application
    Filed: January 22, 2021
    Publication date: May 18, 2023
    Applicant: Hitachi Astemo, Ltd.
    Inventors: Toshiyuki AJIMA, Takafumi HARA, Akihiro ASHIDA, Hirokazu MATSUI, Kiyoshi KURODA