Patents by Inventor Toshiyuki Ajima

Toshiyuki Ajima 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: 11356037
    Abstract: To improve control characteristics of an inverter while suppressing manufacturing cost. An inverter control device 10 is a device for controlling an inverter device 1 having a plurality of switching elements.
    Type: Grant
    Filed: March 12, 2019
    Date of Patent: June 7, 2022
    Assignee: HITACHI ASTEMO, LTD.
    Inventors: Taizou Miyazaki, Toshiyuki Ajima, Toshisada Mitsui
  • Patent number: 11342863
    Abstract: An inverter performs a power conversion operation for converting DC power into AC power, includes an arithmetic control device provided with a voltage command signal generation unit, a synthesis processing unit, and a carrier wave comparison unit. The voltage command signal generation unit has a plurality of control systems, and outputs the first voltage command signal generated based on the first control system among the plurality of control systems, and the second voltage command signal generated based on the second control system different from the first control system among the plurality of control systems. The synthesis processing unit generates a synthesized voltage command signal obtained by synthesizing the first voltage command signal and the second voltage command signal at a predetermined ratio. The carrier wave comparison unit generates a PWM signal which is a gate drive signal for controlling the power conversion operation based on the synthesized voltage command signal.
    Type: Grant
    Filed: July 25, 2019
    Date of Patent: May 24, 2022
    Assignee: HITACHI ASTEMO, LTD.
    Inventors: Takuya Nemoto, Toshiyuki Ajima, Taito Kikuchi
  • Patent number: 11325641
    Abstract: An object of the present invention is to provide an electric power steering apparatus capable of improving reliability of a drive device for a three-phase synchronous motor without increasing a cost of the drive device. A control device for controlling an electric power steering apparatus according to the present invention is a control device for controlling an electric power steering apparatus using a three-phase synchronous motor as a force assisting in a steering operation, includes: a rotational position estimation unit that estimates a position of a rotor of the three-phase synchronous motor on the basis of a neutral point potential or a virtual neutral point potential of the three-phase synchronous motor; and a command signal computing unit that computes a command signal to the three-phase synchronous motor on the basis of the position of the rotor estimated by the rotational position estimation unit.
    Type: Grant
    Filed: June 13, 2016
    Date of Patent: May 10, 2022
    Assignee: Hitachi Astemo, Ltd.
    Inventors: Takafumi Hara, Toshiyuki Ajima, Mitsuo Sasaki, Yoshitaka Iwaji, Shigehisa Aoyagi, Takumi Hisazumi
  • Publication number: 20220029572
    Abstract: An object of the present invention is to provide a power conversion device including a plurality of inverter circuits connected in parallel to a load, the power conversion device being capable of performing control with a smaller number of microcomputers, having high reliability, and being advantageous for miniaturization and cost reduction. Provided are: a plurality of inverter circuits connected in parallel to a load; a microcomputer which controls the plurality of inverter circuits; a plurality of signal selection units which select a drive signal of each of the plurality of inverter circuits; and a first transmission path and a second transmission path which are connected in parallel between the microcomputer and the plurality of signal selection units and transmit the drive signal of each of the plurality of inverter circuits from the microcomputer to each of the plurality of signal selection units.
    Type: Application
    Filed: August 19, 2019
    Publication date: January 27, 2022
    Applicant: Hitachi Astemo, Ltd.
    Inventors: Shigehisa AOYAGI, Toshiyuki AJIMA, Kotaro SHIINO
  • Patent number: 11228271
    Abstract: Provides are a control device for a three-phase synchronous motor in which a position detection accuracy of a rotor can be improved when one three-phase synchronous motor is driven by a plurality of inverters, and an electric power steering device using the same. A control device for a three-phase synchronous motor includes: a three-phase synchronous motor including a first three-phase winding and a second three-phase winding; a first inverter connected to the first three-phase winding; a second inverter connected to the second three-phase winding; a first control device that controls the first inverter on the basis of a rotor position of the three-phase synchronous motor; and a second control device that controls the second inverter on the basis of the rotor position of the three-phase synchronous motor. The first control device estimates the rotor position on a basis of a neutral point potential of the first three-phase winding and a neutral point potential of the second three-phase winding.
    Type: Grant
    Filed: July 13, 2018
    Date of Patent: January 18, 2022
    Assignee: Hitachi Astemo, Ltd.
    Inventors: Takafumi Hara, Shigehisa Aoyagi, Toshiyuki Ajima, Hiroyuki Ota, Yoshitaka Sugiyama
  • Publication number: 20220001845
    Abstract: An object of the present invention is to provide a brake control device and a brake system capable of braking with a shortened braking response when shifting from non-braking to braking. A brake control device 10 includes a command value calculation unit 4 that calculates an operation command value required to make a pressing force by which a brake pad 11a is pressed against a brake disc 11b reach a target thrust value. The command value calculation unit 4 includes: a clearance command calculation unit 43 that calculates a command value required for contact between the brake pad 11a and the brake disc 11b; and a thrust command calculation unit 40 that calculates a command value required for reaching the target thrust from a state where the brake pad 11a and the brake disc 11b are in contact with each other.
    Type: Application
    Filed: August 15, 2019
    Publication date: January 6, 2022
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Kyoshiro ITAKURA, Toshiyuki AJIMA, Takahiro ITO, Kenichiro MATSUBARA, Daisuke GOTO, Makoto MATSUURA
  • Publication number: 20210384859
    Abstract: A random value integration unit 175 outputs a random value output from a random value generation unit 174 in a diffusion width Rand output from a diffusion width generation unit 173 by a product of an output of the random value generation unit 174 and an output of the diffusion width generation unit 173. A triangular wave signal generation unit 176 generates a triangular wave signal corresponding to a second carrier frequency fc2 which is obtained by adding the random value output from the random value integration unit 175 to a first carrier frequency fc1 which is an output of a carrier frequency setting unit 171. That is, a frequency obtained by increasing the diffusion width of the first carrier frequency fc1 is used as the second carrier frequency fc2, and the second carrier frequency is used as the carrier frequency.
    Type: Application
    Filed: September 12, 2019
    Publication date: December 9, 2021
    Applicant: HITACHI ASTEMO, LTD.
    Inventors: Takafumi HARA, Midori TAKAOKA, Toshiyuki AJIMA, Hirokazu MATSUI, Akihiro ASHIDA
  • Patent number: 11196377
    Abstract: In a motor drive device 120, a phase compensation amount calculation unit 110 calculates a phase compensation amount ?? for compensating a voltage phase ?v* when a control mode is switched in a control selection unit 90. The control selection unit 90 outputs the three-phase voltage command Vuvw* according to any one of the plurality of control modes based on the modulation factor Kh*, the voltage phase ?v*, and the phase compensation amount ??. A PWM control unit 100 outputs gate signals Gun, Gup, Gvn, Gvp, Gwn, and Gwv based on the three-phase voltage command Vuvw* and a rotor position ?d. The inverter 20 has a plurality of switching elements, and controls the plurality of switching elements based on gate signals Gun, Gup, Gvn, Gyp, Gwn, and Gwv to drive the AC motor 10.
    Type: Grant
    Filed: November 28, 2018
    Date of Patent: December 7, 2021
    Assignee: HITACHI ASTEMO, LTD.
    Inventors: Midori Takaoka, Junki Isobe, Kohei Myoen, Toshiyuki Ajima, Kazuaki Tobari, Yoshitaka Iwaji
  • Publication number: 20210265936
    Abstract: An object of the present invention is to provide a motor control device capable of estimating a delay with high accuracy even in a case where there is a fluctuation in disturbance torque or delay time and of suppressing the influence of the delay. For this end, the present invention includes a motor MTR, an ECU 2 that controls the rotation of the motor MTR, and an ECU 1 that sends a torque command to the ECU 2 based on a command value. The ECU 1 includes a disturbance estimation block 100 and a delay estimation block 200. The disturbance estimation block 100 estimates disturbance torque (?d) using a torque command input to the ECU 2 and a feedback value of the motor MTR. The delay estimation block 200 estimates a delay using a torque command output from the ECU 1, the feedback value of the motor MTR, and the disturbance torque (?d).
    Type: Application
    Filed: June 17, 2019
    Publication date: August 26, 2021
    Applicant: Hitachi Automotive Systems, Ltd.
    Inventors: Hiroaki SATO, Toshiyuki AJIMA, Kenichiro MATSUBARA, Daisuke GOTO
  • Publication number: 20210242799
    Abstract: To suppress torque fluctuations that occur when switching control systems. The inverter, which performs a power conversion operation for converting DC power into AC power, includes an arithmetic control device INV200 which is provided with a voltage command signal generation unit 620, a synthesis processing unit 670, and a carrier wave comparison unit 680. The voltage command signal generation unit 620 has a plurality of control systems, and outputs the first voltage command signal generated based on the first control system among the plurality of control systems, and the second voltage command signal generated based on the second control system different from the first control system among the plurality of control systems. The synthesis processing unit 670 generates a synthesized voltage command signal obtained by synthesizing the first voltage command signal and the second voltage command signal at a predetermined ratio.
    Type: Application
    Filed: July 25, 2019
    Publication date: August 5, 2021
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Takuya NEMOTO, Toshiyuki AJIMA, Taito KIKUCHI
  • Publication number: 20210197777
    Abstract: An object of the present invention is to appropriately control a clearance amount by correcting an estimation error of a contact position caused by a delay time difference between output signals of sensors, and to establish both improvement of fuel efficiency due to prevention of drag of a brake pad during non-braking and reduction in response time during braking. A brake system includes a brake disc, a brake pad, a piston, a drive mechanism, a position sensor that detects a position of the piston, a thrust sensor that detects a thrust by which the brake pad presses the brake disc, and a brake control unit that adjusts a braking force by controlling the drive mechanism.
    Type: Application
    Filed: March 18, 2019
    Publication date: July 1, 2021
    Applicant: Hitachi Automotive Systems, Ltd.
    Inventors: Kyoshiro ITAKURA, Toshiyuki AJIMA, Kenichiro MATSUBARA, Daisuke GOTO
  • Publication number: 20210119553
    Abstract: To improve control characteristics of an inverter while suppressing manufacturing cost. An inverter control device 10 is a device for controlling an inverter device 1 having a plurality of switching elements.
    Type: Application
    Filed: March 12, 2019
    Publication date: April 22, 2021
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Taizou MIYAZAKI, Toshiyuki AJIMA, Toshisada MITSUI
  • Publication number: 20210091700
    Abstract: Provides are a control device for a three-phase synchronous motor in which a position detection accuracy of a rotor can be improved when one three-phase synchronous motor is driven by a plurality of inverters, and an electric power steering device using the same. A control device for a three-phase synchronous motor includes: a three-phase synchronous motor including a first three-phase winding and a second three-phase winding; a first inverter connected to the first three-phase winding; a second inverter connected to the second three-phase winding; a first control device that controls the first inverter on the basis of a rotor position of the three-phase synchronous motor; and a second control device that controls the second inverter on the basis of the rotor position of the three-phase synchronous motor. The first control device estimates the rotor position on a basis of a neutral point potential of the first three-phase winding and a neutral point potential of the second three-phase winding.
    Type: Application
    Filed: July 13, 2018
    Publication date: March 25, 2021
    Inventors: Takafumi HARA, Shigehisa AOYAGI, Toshiyuki AJIMA, Hiroyuki OTA, Yoshitaka SUGIYAMA
  • Publication number: 20210044243
    Abstract: An object of the present invention is to provide a motor control device that can suppress electromagnetic noises including a switching noise and to an electric vehicle system using the motor control device. A motor control device includes: a power converter that is controlled by a pulse width modulation signal; a motor that is driven by the power converter; and a controller that generates the pulse width modulation signal, based on a carrier signal. When switching between a first carrier frequency (fc1) of the carrier signal and a second carrier frequency (fc2) of the carrier signal, the controller varies proportions of the first carrier frequency and the second carrier frequency in accordance with a number of rotations of the motor, the second carrier frequency being higher than the first carrier frequency.
    Type: Application
    Filed: January 24, 2019
    Publication date: February 11, 2021
    Inventors: Takafumi HARA, Toshiyuki AJIMA, Akihiro ASHIDA
  • Patent number: 10873285
    Abstract: This is to reduce electromagnetic noise while reducing a calculation load of a microcomputer. An inverter drive device according to the present invention switches a first control mode, a second control mode, and a third control mode on the basis of vehicle speed information in a motor control device that controls a power converter that drives a polyphase motor by a PWM pulse signal based on a carrier signal, the first control mode being for updating a command voltage signal to the power converter only on a ridge side or a trough side of the carrier signal, the second control mode being for updating a command voltage signal to the power converter both on a ridge side and a trough side of the carrier signal, and the third control mode being for updating a command voltage signal to the power converter only once of ridge-trough-ridge or trough-ridge-trough of the carrier signal.
    Type: Grant
    Filed: November 10, 2017
    Date of Patent: December 22, 2020
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Takafumi Hara, Toshiyuki Ajima, Katsuhiro Hoshino, Akihiro Ashida, Kazuto Oyama
  • Publication number: 20200389117
    Abstract: In a motor drive device 120, a phase compensation amount calculation unit 110 calculates a phase compensation amount ?? for compensating a voltage phase ?v* when a control mode is switched in a control selection unit 90. The control selection unit 90 outputs the three-phase voltage command Vuvw* according to any one of the plurality of control modes based on the modulation factor Kh*, the voltage phase ?v*, and the phase compensation amount ??. A PWM control unit 100 outputs gate signals Gun, Gup, Gvn, Gvp, Gwn, and Gwv based on the three-phase voltage command Vuvw* and a rotor position ?d. The inverter 20 has a plurality of switching elements, and controls the plurality of switching elements based on gate signals Gun, Gup, Gvn, Gyp, Gwn, and Gwv to drive the AC motor 10.
    Type: Application
    Filed: November 28, 2018
    Publication date: December 10, 2020
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Midori TAKAOKA, Junki ISOBE, Kohei MYOEN, Toshiyuki AJIMA, Kazuaki TOBARI, Yoshitaka IWAJI
  • Patent number: 10826410
    Abstract: An object of the present invention is to reduce output voltage errors of an inverter circuit and stably control a motor until the motor reaches high speed rotation. An inverter device includes a PWM controller that generates a PWM pulse for converting DC voltage to AC voltage in accordance with an output request of a motor, and an inverter circuit that converts the DC voltage to the AC voltage with the PWM pulse generated by the PWM controller and drives a motor. The PWM controller changes the pulse width of the PWM pulse at predetermined timing on the upper side of the trapezoidal wave when the trapezoidal wave modulation using the trapezoidal wave is performed in the overmodulation region.
    Type: Grant
    Filed: January 18, 2018
    Date of Patent: November 3, 2020
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Toshiyuki Ajima, Junki Isobe, Midori Takaoka, Akihiro Ashida, Hiroshi Tamura
  • Publication number: 20200244203
    Abstract: Disclosed are a motor control device that can accurately estimate a rotor position based on a neutral point potential even when a load increases, and a brake control device that is driven by the motor control device. The motor control device 3 includes a three-phase synchronous motor 4 including a three-phase winding, an inverter 31 connected to the three-phase winding, a control unit 6 for controlling the inverter based on a rotor position of the three-phase synchronous motor, and a rotational position estimation unit 2 for estimating a rotor position ?d based on a neutral point potential Vn of the three-phase winding. The rotational position estimation unit estimates a rotor position selectively using one or more of a plurality of detected values of the neutral point potential according to a pre-estimated value of the rotor position and a voltage application state to the three-phase winding.
    Type: Application
    Filed: October 10, 2018
    Publication date: July 30, 2020
    Inventors: Takafumi HARA, Toshiyuki AJIMA, Shigehisa AOYAGI, Hiroyuki OTA, Kenichiro MATSUBARA
  • Patent number: 10511249
    Abstract: A motor driving device controls driving of an inverter device, detects current values in two phases, and compensates a value. The motor driving device detects current values in two phases, namely, a maximum phase current value and a minimum phase current value, within a single cycle of a PWM carrier frequency. The motor driving device compensates a value obtained by subtracting an absolute value of a difference between two absolute values, namely, the detected maximum phase current value and minimum phase current value, from the smaller value of the absolute values, as the offset current component.
    Type: Grant
    Filed: July 29, 2016
    Date of Patent: December 17, 2019
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Masahiro Seo, Toshiyuki Ajima, Shigehisa Aoyagi, Takafumi Hara, Masaki Kashima, Yawara Kato
  • Publication number: 20190363646
    Abstract: An object of the present invention is to reduce output voltage errors of an inverter circuit and stably control a motor until the motor reaches high speed rotation. An inverter device includes a PWM controller that generates a PWM pulse for converting DC voltage to AC voltage in accordance with an output request of a motor, and an inverter circuit that converts the DC voltage to the AC voltage with the PWM pulse generated by the PWM controller and drives a motor. The PWM controller changes the pulse width of the PWM pulse at predetermined timing on the upper side of the trapezoidal wave when the trapezoidal wave modulation using the trapezoidal wave is performed in the overmodulation region.
    Type: Application
    Filed: January 18, 2018
    Publication date: November 28, 2019
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Toshiyuki AJIMA, Junki ISOBE, Midori TAKAOKA, Akihiro ASHIDA, Hiroshi TAMURA