Patents by Inventor Kenichi Akita

Kenichi Akita 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: 20150091534
    Abstract: A field current limiting section includes a field current limitation instructing section for, when a field current limitation determining section determines that a determination value has reached a predetermined determination threshold value, generating a field current limiting instruction to a field current control section so as to limit field current to be equal to or smaller than a predetermined permissible value during a predetermined field current limitation time Tlim. A field current limitation releasing section outputs a field current limitation releasing instruction to the field current limiting section so as to release limitation of the field current during a predetermined field current limitation release time TC. When having received the field current limitation releasing instruction from the field current limitation releasing section, the field current limiting section releases limitation of the field current during the predetermined field current limitation release time.
    Type: Application
    Filed: September 19, 2012
    Publication date: April 2, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kenichi Akita, Masato Mori, Mitsunori Tabata
  • Publication number: 20150048773
    Abstract: A field winding rotating electrical machine includes a field current detection section, a field current control section configured to calculate a duty ratio of a current supplied to the field winding based on a field current detection value, to thereby control current supply to the field winding by using a switching element, and a field current correction section configured to estimate a time point when the field current becomes 0 A based on a control state of the field current, to specify the field current detection value at the estimated time point to be a field current correction value, and to subtract the field current correction value from the field current detection value, to thereby calculate the corrected field current value. The field current control section controls the current supply based on the corrected field current value calculated by the field current correction section.
    Type: Application
    Filed: May 15, 2012
    Publication date: February 19, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kenichi Akita, Masato Mori, Mitsunori Tabata
  • Publication number: 20150019059
    Abstract: Provided are a power converter for a vehicle generator-motor and a method for controlling a vehicle generator-motor, which is used for a field winding type vehicle generator-motor configured to perform control in accordance with an external operating command in which a power converter is connected to a rotating electrical machine including a field winding and an armature winding. When the generator-motor shifts from a driving state to another operating mode, a method of stopping a driving mode is switched in accordance with an operating mode to be shifted, to thereby shift the operating mode promptly without generating an unintended power generation, an excess power generation, and an excess torque fluctuation.
    Type: Application
    Filed: March 7, 2012
    Publication date: January 15, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Mitsunori Tabata, Masato Mori, Kenichi Akita
  • Publication number: 20140322874
    Abstract: A charge storage layer interposed between a memory gate electrode and a semiconductor substrate is formed shorter than a gate length of the memory gate electrode or a length of insulating films so as to make the overlapping amount of the charge storage layer and a source region to be less than 40 nm. Therefore, in the write state, since the movement in the transverse direction of the electrons and the holes locally existing in the charge storage layer decreases, the variation of the threshold voltage when holding a high temperature can be reduced. In addition, the effective channel length is made to be 30 nm or less so as to reduce an apparent amount of holes so that coupling of the electrons with the holes in the charge storage layer decreases; therefore, the variation of the threshold voltage when holding at room temperature can be reduced.
    Type: Application
    Filed: July 8, 2014
    Publication date: October 30, 2014
    Inventors: Kenichi Akita, Daisuke Okada, Keisuke Kuwahara, Yasufumi Morimoto, Yasuhiro Shimamoto, Kan Yasui, Tsuyoshi Arigane, Tetsuya Ishimaru
  • Publication number: 20140292286
    Abstract: A control section is configured to, when it is detected that a voltage of a B-terminal of a power generator has exceeded a first predetermined voltage value, turn on all switching elements of a negative arm of a bridge circuit connected to one set of armature windings and turn off all switching elements of a positive arm, and reduce a field current flowing in a field winding. The control section is configured to thereafter turn off all the turned-on switching elements when a predetermined condition is satisfied.
    Type: Application
    Filed: December 15, 2011
    Publication date: October 2, 2014
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Mitsunori Tabata, Masato Mori, Kenji Nakajima, Kenichi Akita
  • Publication number: 20140292240
    Abstract: Provided are a low-cost control device and the like for a vehicle generator-motor for minimizing the number of current sensors and the like, and estimating an output torque and a current consumption during drive of the generator-motor. The output torque and the current consumption during the drive of the generator-motor are estimated based on a field current, an rpm, a DC voltage, and a phase of an AC voltage to be supplied of the generator-motor, without providing a current sensor for detecting an input current from a power supply to an inverter device of the generator-motor, and a current sensor for detecting an output current from the inverter device to an armature winding of a rotary electric machine.
    Type: Application
    Filed: October 15, 2013
    Publication date: October 2, 2014
    Applicant: Mitsubishi Electric Corporation
    Inventors: Mitsunori TABATA, Masato MORI, Kenichi AKITA
  • Patent number: 8829863
    Abstract: A field winding type rotary electric machine includes: a controller; a field current integration portion provided in the controller to calculate an integral value by integrating an excessive field current exceeding a field current threshold; a field current limiting portion provided in the controller and carrying out limiting processing to limit a field current to or below a predetermined value when the integral value reaches an integral value threshold defined as a reference value at or above which the field current is limited; a controller power supply connection switch switched ON and OFF for power feeding to the controller; a controller power supply connection determination portion switching ON and OFF the controller power supply connection switch; and a power feeding ON state maintaining portion maintaining an ON state of the power feeding to the controller from start to end of the limiting processing by the field current limiting portion.
    Type: Grant
    Filed: December 16, 2011
    Date of Patent: September 9, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenichi Akita, Kenji Nakajima, Masato Mori, Mitsunori Tabata
  • Patent number: 8818674
    Abstract: Provided is a vehicle behavior controller capable of stabilizing a behavior of a vehicle with a high response when an unstable state of the vehicle is judged. The vehicle behavior controller includes: a running state detecting unit for detecting a running state of the vehicle; an unstable state judging unit for judging the unstable state of the vehicle based on the running state; a motor generator connected to an engine of the vehicle, the motor generator operating as a power generator for using an output of a prime mover to generate power and an electric motor for assisting the output of the prime mover; and a control unit for controlling an operation of the motor generator based on r.p.m. of the motor generator, in which the control unit controls the operation of the motor generator to generate braking torque when the unstable state is judged.
    Type: Grant
    Filed: April 24, 2009
    Date of Patent: August 26, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenji Nakajima, Masato Mori, Kenichi Akita
  • Patent number: 8796756
    Abstract: A charge storage layer interposed between a memory gate electrode and a semiconductor substrate is formed shorter than a gate length of the memory gate electrode or a length of insulating films so as to make the overlapping amount of the charge storage layer and a source region to be less than 40 nm. Therefore, in the write state, since the movement in the transverse direction of the electrons and the holes locally existing in the charge storage layer decreases, the variation of the threshold voltage when holding a high temperature can be reduced. In addition, the effective channel length is made to be 30 nm or less so as to reduce an apparent amount of holes so that coupling of the electrons with the holes in the charge storage layer decreases; therefore, the variation of the threshold voltage when holding at room temperature can be reduced.
    Type: Grant
    Filed: January 31, 2013
    Date of Patent: August 5, 2014
    Assignee: Renesas Electronics Corporation
    Inventors: Kenichi Akita, Daisuke Okada, Keisuke Kuwahara, Yasafumi Morimoto, Yasuhiro Shimamoto, Kan Yasui, Tsuyoshi Arigane, Tetsuya Ishimaru
  • Publication number: 20140151622
    Abstract: A superlattice phase change memory capable of increasing a resistance in a low resistance state is provided. The phase change memory includes a first electrode, a second electrode provided on the first electrode, and a phase change memory layer having a superlattice structure between the first electrode and the second electrode, the superlattice structure including to repeatedly formed layers of Sb2Te3 and GeTe. The phase change memory layer having the superlattice structure includes a Sb2Te3 layer containing Zr in contact with the first electrode.
    Type: Application
    Filed: November 27, 2013
    Publication date: June 5, 2014
    Inventors: Takasumi Oyanagi, Norikatsu Takaura, Mitsuharu Tai, Masaharu Kinoshita, Takahiro Morikawa, Kenichi Akita, Masahito Kitamura
  • Patent number: 8736234
    Abstract: A power converter control apparatus includes a power converter part having a bridge circuit formed of a switching element and a field circuit controlling conduction of a field winding in an AC generator, and a control apparatus part having a field current detector, a temperature detector detecting a temperature of a generator part, the power converter part, or the control apparatus part, a field current instruction computation portion computing a field current instruction value of the generator, a temperature rise suppression portion computing a generated current suppression value on the basis of an output of the temperature detector and computing a field current suppression value on the basis of the computed generated current suppression value, a field current instruction selection portion selecting the field current instruction value or the field current suppression value whichever is the smaller, and a field current control portion controlling a field current.
    Type: Grant
    Filed: October 11, 2011
    Date of Patent: May 27, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenji Nakajima, Masato Mori, Kenichi Akita, Mitsunori Tabata
  • Patent number: 8736235
    Abstract: A power-generation motor control system is a control system that controls a power-generation motor provided with an armature and a magnetic-field winding, and is characterized in that when the power-generation motor is operated as a motor, before a power source energizes the armature, a preliminary excitation current, with the value of which the induction voltage across the armature does not exceed the voltage of the power source, is applied to the magnetic-field winding in accordance with the rotation speed of the power-generation motor so that preliminary excitation of the power-generation motor is performed.
    Type: Grant
    Filed: October 17, 2011
    Date of Patent: May 27, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Mitsunori Tabata, Masato Mori, Kenji Nakajima, Kenichi Akita
  • Patent number: 8704400
    Abstract: A vehicle power converter including a plurality of switching elements having diodes connected thereto in parallel and constituting a multi-phase bridge circuit and a controller for conducting the switching element corresponding to each diode in synchronization with a conduction state of the diode concerned to perform synchronous rectification and is connected between a power generator-motor driven from the external to generate multi-phase AC power and DC equipment, further includes a load state detecting unit for detecting a load state of the power generator-motor when the multi-phase AC power occurs, wherein a shift from diode rectification to synchronous rectification or a shift from the synchronous rectification to the diode rectification is carried out in accordance with an output of the load state detecting unit.
    Type: Grant
    Filed: November 2, 2009
    Date of Patent: April 22, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenji Nakajima, Kenichi Akita, Masato Mori, Mitsunori Tabata, Katsuya Tsujimoto
  • Patent number: 8680796
    Abstract: To provide an upper limit of a generated voltage or generated torque, to thereby prevent the occurrence of an overvoltage or excessive torque during power generation, a control selection section (308) chooses and outputs a minimum value between a control output of a generated voltage control section (306) for controlling a field current so that a B-terminal voltage of a polyphase AC generator-motor coincides with a generated voltage command and a control output of a generated torque control section (307) for controlling, based on the B-terminal voltage and a rotation speed, the field current so that generated torque of the polyphase AC generator-motor coincides with a generated torque command.
    Type: Grant
    Filed: April 10, 2012
    Date of Patent: March 25, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenji Nakajima, Masato Mori, Kenichi Akita, Mitsunori Tabata
  • Patent number: 8680819
    Abstract: A field winding type rotary electric machine includes a motor generator; a field current detection unit; a field current control unit which controls a field current; a field current limiting determination section which calculates a field current integration value and determines whether or not the field current integration value reaches a predetermined field current integration threshold value; and a field current limiting command section which, when it is determined that the field current integration value reaches the predetermined field current integration threshold value, outputs a command which sets the field current to be lower than or equal to a predetermined field current limiting value to the field current control unit during a predetermined limiting time, and outputs a command which changes the predetermined limiting time depending on the field current. Accordingly, a temperature rise of the machine is suppressed and limiting of the field current can be released as needed.
    Type: Grant
    Filed: March 28, 2011
    Date of Patent: March 25, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenichi Akita, Masato Mori, Kenji Nakajima, Mitsunori Tabata
  • Publication number: 20130140622
    Abstract: A charge storage layer interposed between a memory gate electrode and a semiconductor substrate is formed shorter than a gate length of the memory gate electrode or a length of insulating films so as to make the overlapping amount of the charge storage layer and a source region to be less than 40 nm. Therefore, in the write state, since the movement in the transverse direction of the electrons and the holes locally existing in the charge storage layer decreases, the variation of the threshold voltage when holding a high temperature can be reduced. In addition, the effective channel length is made to be 30 nm or less so as to reduce an apparent amount of holes so that coupling of the electrons with the holes in the charge storage layer decreases; therefore, the variation of the threshold voltage when holding at room temperature can be reduced.
    Type: Application
    Filed: January 31, 2013
    Publication date: June 6, 2013
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventors: Kenichi Akita, Daisuke Okada, Keisuke Kuwahara, Yasufumi Morimoto, Yasuhiro Shimamoto, Kan Yasui, Tsuyoshi Arigane, Tetsuya Ishimaru
  • Publication number: 20130093366
    Abstract: To provide an upper limit of a generated voltage or generated torque, to thereby prevent the occurrence of an overvoltage or excessive torque during power generation, a control selection section (308) chooses and outputs a minimum value between a control output of a generated voltage control section (306) for controlling a field current so that a B-terminal voltage of a polyphase AC generator-motor coincides with a generated voltage command and a control output of a generated torque control section (307) for controlling, based on the B-terminal voltage and a rotation speed, the field current so that generated torque of the polyphase AC generator-motor coincides with a generated torque command.
    Type: Application
    Filed: April 10, 2012
    Publication date: April 18, 2013
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kenji NAKAJIMA, Masato MORI, Kenichi AKITA, Mitsunori TABATA
  • Patent number: 8390053
    Abstract: A charge storage layer interposed between a memory gate electrode and a semiconductor substrate is formed shorter than a gate length of the memory gate electrode or a length of insulating films so as to make the overlapping amount of the charge storage layer and a source region to be less than 40 nm. Therefore, in the write state, since the movement in the transverse direction of the electrons and the holes locally existing in the charge storage layer decreases, the variation of the threshold voltage when holding a high temperature can be reduced. In addition, the effective channel length is made to be 30 nm or less so as to reduce an apparent amount of holes so that coupling of the electrons with the holes in the charge storage layer decreases; therefore, the variation of the threshold voltage when holding at room temperature can be reduced.
    Type: Grant
    Filed: August 8, 2008
    Date of Patent: March 5, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Kenichi Akita, Daisuke Okada, Keisuke Kuwahara, Yasufumi Morimoto, Yasuhiro Shimamoto, Kan Yasui, Tsuyoshi Arigane, Tetsuya Ishimaru
  • Patent number: 8339074
    Abstract: Generation voltage control or generation torque control is performed as suitable control based on an external command or a load of a generator motor, to thereby prevent a rapid change of a generation torque or excessive power generation. A power converter control apparatus includes: a power conversion unit including a bridge circuit for controlling energization of an armature winding and a field circuit for controlling energization of a field winding; and a control device including B-terminal voltage detection means, field current detection means, generation voltage control means, generation torque control means, and control selection means. The control selection means selects the one of the generation voltage control means and the generation torque control means based on one of a command from an outside and a load of the generator motor.
    Type: Grant
    Filed: June 16, 2010
    Date of Patent: December 25, 2012
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenji Nakajima, Masato Mori, Kenichi Akita, Mitsunori Tabata
  • Patent number: 8334680
    Abstract: Provided is a field winding type generator-motor capable of minimizing cost increase and structure modification while preventing a failure due to a temperature rise, without mounting a temperature sensor. The field winding type generator-motor according to the present invention includes: a dynamo-electric machine that has a field winding; a field current detecting section for detecting field current; a field current restriction deciding section for deciding whether or not the decision value has reached a predetermined decision threshold value by calculating a decision value based on the field current detected by the field current detecting section; and a field current controller for controlling the field current flowing in the field winding so that the field current is restricted to a predetermined permissible value in a case where the field current restriction deciding section decides that the decision value has reached the predetermined decision threshold value.
    Type: Grant
    Filed: November 16, 2009
    Date of Patent: December 18, 2012
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenichi Akita, Kenji Nakajima, Masato Mori