Patents by Inventor Shigehisa Aoyagi

Shigehisa Aoyagi 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: 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
  • Patent number: 10924048
    Abstract: An inverter control device including at least first and second inverters includes: a current detector that detects a current flowing through a main circuit of the first inverter; a current controller that generates a voltage command value of the first inverter on the basis of a detected current and a current command; and a voltage command predictor that generates a voltage command value of the second inverter on the basis of a variation of the voltage command value of the first inverter.
    Type: Grant
    Filed: November 22, 2016
    Date of Patent: February 16, 2021
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Hiroshi Tamura, Hiroshi Aoyagi, Tomishige Yatsugi, Shigehisa Aoyagi
  • Publication number: 20200412284
    Abstract: An applied voltage decision unit 510 performs in parallel, a process of determining three-phase AC commands V1u* to V1w* of a voltage applied to a motor by an inverter based on a position, of a rotor of a motor, detected by a position sensor with an output A, and a process of determining three-phase AC commands V2u* to V2w* of the voltage applied to the motor by the inverter based on a neutral point voltage VN of the motor. A PWM modulator 507 alternately outputs a PWM signal according to the three-phase AC commands V1u* to V1w* and a PWM signal according to the three-phase AC commands V2u* to V2w* to the inverter. A control device determines whether or not the position sensor with the output A has failed by comparing the position, of the rotor, detected by the position sensor with the output A with a position, of the rotor, estimated from a neutral point voltage VN of the motor.
    Type: Application
    Filed: January 17, 2019
    Publication date: December 31, 2020
    Inventors: Shigehisa AOYAGI, Takafumi HARA, Yoshitaka SUGIYAMA, Masaki KASHIMA
  • Publication number: 20200280278
    Abstract: An inverter control device including at least first and second inverters includes: a current detector that detects a current flowing through a main circuit of the first inverter; a current controller that generates a voltage command value of the first inverter on the basis of a detected current and a current command; and a voltage command predictor that generates a voltage command value of the second inverter on the basis of a variation of the voltage command value of the first inverter.
    Type: Application
    Filed: November 22, 2016
    Publication date: September 3, 2020
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Hiroshi TAMURA, Hiroshi AOYAGI, Tomishige YATSUGI, Shigehisa AOYAGI
  • Patent number: 10745045
    Abstract: A power steering device includes a steering mechanism, an electric motor for applying a steering assist force to the steering mechanism, and a first motor rotational position sensor for sensing as an actual axis phase a rotational position of a rotor of the electric motor. A control device is configured to: receive input of a signal of first actual axis phase outputted from the first motor rotational position sensor; receive input of a signal of value of electric current flowing through the electric motor; estimate as a control phase a phase of an induced voltage occurring in the electric motor, based on the signal of value of electric current; and determine whether or not the first motor rotational position sensor is abnormal, based on a difference between the first actual axis phase and the control phase.
    Type: Grant
    Filed: July 29, 2016
    Date of Patent: August 18, 2020
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Mitsuo Sasaki, Takumi Hisazumi, Shigehisa Aoyagi
  • 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: 10700627
    Abstract: To control an inverter in the event of an arm failure of a power converter, fluctuation in an output torque is suppressed, and reduction of a total output caused by the failure is suppressed by distributing an output into a plurality of inverters. A power converter for driving a redundant motor having a pair of first and second independent coils, includes: a first inverter circuit connected to the first coil; a second inverter circuit, independent from the first inverter circuit, connected to the second coil; and a first phase relay provided between the first inverter circuit and the first coil. When any one of a plurality of arms of the first inverter circuit fails, the first phase relay shuts off conduction between the failed arm and the first coil, and the redundant motor is driven by operating the second inverter circuit and the remaining arms of the first inverter circuit.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: June 30, 2020
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Shigehisa Aoyagi, Tomonobu Koseki
  • 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
  • Patent number: 10411621
    Abstract: In the drive device for a three-phase synchronous motor, if one of the two rotational position detectors is defective, it is necessary to identify the rotational position detector having abnormal output and is in the detective state. To do this, three or more rotational position detectors are required, which increases costs of the rotational position detectors. By comparing the outputs of two rotational position detectors, an abnormality of ether one of the two detectors is detected. The abnormal detector is identified with the use of rotational position estimating means. The drive of the three-phase synchronous motor is controlled with the use of the output ? of the properly functioning one of the first and second rotational position detectors.
    Type: Grant
    Filed: June 14, 2016
    Date of Patent: September 10, 2019
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Takafumi Hara, Toshiyuki Ajima, Shigehisa Aoyagi, Mitsuo Sasaki, Takumi Hisazumi
  • Patent number: 10348218
    Abstract: An object of the invention is to simultaneously solve a miniaturization and an improvement of productivity of a power conversion device, a temperature rise suppression of a smoothing capacitor, and a reduction of motor noises. The power conversion device of the invention includes a smoothing capacitor, a first power conversion unit and a second power conversion unit which are connected in parallel, and a control unit which generates a PWM pulse on the basis of an output voltage vector and a PWM carrier. The control unit includes a correction unit which corrects a predetermined output voltage vector value to two or more different output voltage vector values such that an average value in one period of the PWM carrier becomes the predetermined output voltage vector value. The correction unit corrects a first output voltage vector value in a first period, and corrects a second output voltage vector value in a second period different from the first period.
    Type: Grant
    Filed: September 16, 2015
    Date of Patent: July 9, 2019
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Takuro Kanazawa, Kimihisa Furukawa, Shigehisa Aoyagi
  • Publication number: 20190074790
    Abstract: To control an inverter in the event of an arm failure of a power converter, fluctuation in an output torque is suppressed, and reduction of a total output caused by the failure is suppressed by distributing an output into a plurality of inverters. A power converter for driving a redundant motor having a pair of first and second independent coils, includes: a first inverter circuit connected to the first coil; a second inverter circuit, independent from the first inverter circuit, connected to the second coil; and a first phase relay provided between the first inverter circuit and the first coil. When any one of a plurality of arms of the first inverter circuit fails, the first phase relay shuts off conduction between the failed arm and the first coil, and the redundant motor is driven by operating the second inverter circuit and the remaining arms of the first inverter circuit.
    Type: Application
    Filed: October 31, 2016
    Publication date: March 7, 2019
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Shigehisa AOYAGI, Tomonobu KOSEKI
  • Publication number: 20190023309
    Abstract: A power steering device includes a steering mechanism, an electric motor for applying a steering assist force to the steering mechanism, and a first motor rotational position sensor for sensing as an actual axis phase a rotational position of a rotor of the electric motor. A control device is configured to: receive input of a signal of first actual axis phase outputted from the first motor rotational position sensor; receive input of a signal of value of electric current flowing through the electric motor; estimate as a control phase a phase of an induced voltage occurring in the electric motor, based on the signal of value of electric current; and determine whether or not the first motor rotational position sensor is abnormal, based on a difference between the first actual axis phase and the control phase.
    Type: Application
    Filed: July 29, 2016
    Publication date: January 24, 2019
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Mitsuo SASAKI, Takumi HISAZUMI, Shigehisa AOYAGI
  • Publication number: 20190013761
    Abstract: An object of the present invention is to provide an inverter driving device and an electric system which are capable of accurately detecting an offset amount of a current detection circuit that detects a motor current using a direct bus current, and compensating for the detected offset amount, to improve detection accuracy of the motor current and control the motor appropriately, without increasing the number of components of the inverter driving device.
    Type: Application
    Filed: July 29, 2016
    Publication date: January 10, 2019
    Applicant: Hitachi Automotive Systems, Ltd.
    Inventors: Masahiro SEO, Toshiyuki AJIMA, Shigehisa AOYAGI, Takafumi HARA, Masaki KASHIMA, Yawara KATO
  • Publication number: 20180201303
    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: Application
    Filed: June 13, 2016
    Publication date: July 19, 2018
    Inventors: Takafumi HARA, Toshiyuki AJIMA, Mitsuo SASAKI, Yoshitaka IWAJI, Shigehisa AOYAGI, Takumi HISAZUMI
  • Publication number: 20180194388
    Abstract: An object of the present invention is to realize high-performance motor driving control by detecting DC currents to reproduce AC currents with high accuracy in an electric power converter in which a plurality of inverters are connected to a motor either independently or in parallel. The present invention is characterized in that a predetermined current detection period in which a first current detection section detects a DC current of a first inverter is controlled in such a manner that the predetermined current detection period does not overlap at least timing of changing over between on-timing and off-timing of a switching element that configures a second inverter. More preferably, the predetermined current detection period in which the first current detection section detects the DC current of the first inverter is controlled in such a manner that the predetermined current detection period does not overlap periods in which a current is carried to the second current detection section.
    Type: Application
    Filed: June 27, 2016
    Publication date: July 12, 2018
    Inventor: Shigehisa AOYAGI
  • Publication number: 20180191283
    Abstract: Provided is a motor control device that realizes a high power drive and keeps a steering feeling having a good responsiveness with respect to an operation amount of a steering wheel like an electric power steering device while suppressing an input current to be equal to or lower than a predetermined value in response to a power source management as a vehicle. The motor control device of the invention includes an inverter which converts a DC input current from a DC voltage source into an AC current on the basis of a rotor phase of a motor and outputs the AC current. In a range in which an input current to the inverter does not exceed a predetermined upper limit while keeping a torque current, a maximum weak field current is calculated by a weak field current command calculation unit and is conducted.
    Type: Application
    Filed: June 14, 2016
    Publication date: July 5, 2018
    Inventors: Shigehisa AOYAGI, Toshiyuki AJIMA, Masaki KASHIMA, Hiroyuki OOTA
  • Publication number: 20180183366
    Abstract: In the drive device for a three-phase synchronous motor, if one of the two rotational position detectors is defective, it is necessary to identify the rotational position detector having abnormal output and is in the detective state. To do this, three or more rotational position detectors are required, which increases costs of the rotational position detectors. By comparing the outputs of two rotational position detectors, an abnormality of ether one of the two detectors is detected. The abnormal detector is identified with the use of rotational position estimating means. The drive of the three-phase synchronous motor is controlled with the use of the output ? of the properly functioning one of the first and second rotational position detectors.
    Type: Application
    Filed: June 14, 2016
    Publication date: June 28, 2018
    Inventors: Takafumi HARA, Toshiyuki AJIMA, Shigehisa AOYAGI, Mitsuo SASAKI, Takumi HISAZUMI
  • Patent number: 9831814
    Abstract: An electric motor drive control device includes: an inverter circuit that converts DC power inputted via a DC bus to multiphase AC power and outputs the multiphase AC power to an electric motor; a current detector that detects a DC current flowing in the DC bus; a PWM generator that generates PWM signals and outputs the PWM signals to the inverter circuit; a current calculator that calculates a current value for each of phases to be flowed to the electric motor based upon a value of the DC current and the PWM signals; and a current controller that generates a command signal based upon the current value, and outputs the command signal to the PWM generator, wherein: if one of the phases of the AC power has become missing, the current calculator determines which phase is one that has become missing and calculates current values for other phases.
    Type: Grant
    Filed: August 21, 2015
    Date of Patent: November 28, 2017
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Toshiyuki Ajima, Mitsuo Sasaki, Shigehisa Aoyagi, Tomonobu Koseki, Tomio Sakashita
  • Publication number: 20170331395
    Abstract: An object of the invention is to simultaneously solve a miniaturization and an improvement of productivity of a power conversion device, a temperature rise suppression of a smoothing capacitor, and a reduction of motor noises. The power conversion device of the invention includes a smoothing capacitor, a first power conversion unit and a second power conversion unit which are connected in parallel, and a control unit which generates a PWM pulse on the basis of an output voltage vector and a PWM carrier. The control unit includes a correction unit which corrects a predetermined output voltage vector value to two or more different output voltage vector values such that an average value in one period of the PWM carrier becomes the predetermined output voltage vector value. The correction unit corrects a first output voltage vector value in a first period, and corrects a second output voltage vector value in a second period different from the first period.
    Type: Application
    Filed: September 16, 2015
    Publication date: November 16, 2017
    Inventors: Takuro KANAZAWA, Kimihisa FURUKAWA, Shigehisa AOYAGI
  • Patent number: 9531305
    Abstract: An objective of the present invention is to improve current detection accuracy and to reduce noise of carrier frequency. A motor apparatus and a motor drive apparatus calculate motor currents Iu, Iv, and Iw using a DC bus current detected value Idc of an inverter and control a magnitude and a phase of an applied voltage of a motor to drive the motor. A carrier adjuster decreases a carrier frequency Fc of the inverter if a motor output is relatively larger and that increases the carrier frequency Fc of the inverter if the motor output is relatively smaller. A pulse shift adjuster shifts an interphase waveform of a PWM pulse according to the carrier frequency Fc.
    Type: Grant
    Filed: February 27, 2014
    Date of Patent: December 27, 2016
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Toshiyuki Ajima, Kimihisa Furukawa, Shigehisa Aoyagi, Tohma Yamaguchi, Daisuke Goto, Masaki Kashima