Patents by Inventor Masaki Okamura

Masaki Okamura 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: 20130002174
    Abstract: A control device for a motor drive system including an AC motor having a magnet in a rotor, a converter, and an inverter generates a step-up command value for the converter based on a torque command value for the AC motor. The control device determines whether or not to carry out field-weakening control for increasing a current in a direction weakening force of a magnet that is supplied from the inverter to the AC motor, based on the step-up command value and a state of drive of the AC motor. When field-weakening control should be carried out and when an absolute value of the torque command value is smaller than a threshold value, the control device further increases the generated step-up command value. By doing so, an amount of a field-weakening current can be decreased and therefore efficiency of the motor drive system can be improved.
    Type: Application
    Filed: April 21, 2010
    Publication date: January 3, 2013
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Masaki Okamura, Naoyoshi Takamatsu
  • Patent number: 8324856
    Abstract: In the hybrid vehicle, a boost converter is controlled to make a post-boost voltage or a voltage on the side of an inverter become a target post-boost voltage corresponding to a target operation point of a motor in accordance with a target post-boost voltage setting map that divides an operation region of the motor into a non-boost region and a boost region when a operation point of the motor is included in the boost region. The target post-boost voltage setting map is prepared so that the non-boost region includes a region in which a loss produced by driving the motor when not boosting the post-boost voltages becomes smaller than the loss produced when boosting the post-boost voltage and the boost region includes a region in which the loss produced when boosting the post-boost voltage becomes smaller than the loss produced when not boosting the post-boost voltage.
    Type: Grant
    Filed: December 19, 2008
    Date of Patent: December 4, 2012
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Toshifumi Yamakawa, Hideto Hanada, Kazuhito Hayashi, Masayoshi Suhama, Masaki Okamura
  • Patent number: 8305018
    Abstract: If it is determined that excess power is generated based on overcharge information of a power storage device, a controller starts an operation of consuming the excess power by an excessive power consuming circuit. The controller counts elapsed time from the time point when the power consuming operation started, and if the counted elapsed time exceeds a minimum on-time set in advance, switches the excessive power consuming circuit from active to inactive state. The minimum on-time is set based on a pattern that is expected to cause generation of excessive regenerative power from an AC electric motor because of abrupt change in running status of an electric powered vehicle mounting a motor drive system.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: November 6, 2012
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Masaki Okamura
  • Patent number: 8269446
    Abstract: When an electric vehicle outputs a torque instruction, firstly, a request torque is acquired and a judged whether the acquired request torque is positive or negative. Regardless of the sign of the request torque, it is judged whether the eco-switch is ON. If the request torque has a positive sign and the eco-switch is OFF, a map A is selected. If the eco-switch is ON, a map B which limits the maximum torque to a low value for the map A is selected. If the request torque has a negative sign, a map C is selected regardless of the eco-switch ON/OFF state and the maximum torque is not limited.
    Type: Grant
    Filed: June 30, 2011
    Date of Patent: September 18, 2012
    Assignees: Toyota Jidosha Kabushiki Kaisha, Aisin AW Co., Ltd.
    Inventors: Masayoshi Suhama, Hideto Hanada, Masaki Okamura, Hiroaki Kioka, Ken Iwatsuki
  • Patent number: 8215425
    Abstract: In response to a starting instruction of an engine 22 at a gearshift position of a gearshift lever 81 set to a parking position, the engine 22 and motors MG1 and MG2 are controlled to motor and start the engine 22 with output of a torque from the motor MG2 to keep a rotational position of a rotor in the motor MG2 at a preset reference position. This arrangement enables the engine 22 to be motored and started even in the state of separation of a ring gear shaft 32a from a driveshaft 36 by means of a transmission 60 and locking of drive wheels 39a and 39b by means of a parking lock mechanism 90.
    Type: Grant
    Filed: February 23, 2007
    Date of Patent: July 10, 2012
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Kazuhito Hayashi, Masaki Okamura, Hideto Hanada
  • Patent number: 8169199
    Abstract: It is determined that a periodic zero current stagnation state is reached to correct a voltage command of a smoothing capacitor downward by a predetermined voltage when a state where a current (reactor current) flowing through a coil in a dead time when switching elements are both off immediately after the switching element (upper arm) is turned off from on stagnates at a value of 0 occurs at switching periods of the switching elements. This can prevent a voltage of the smoothing capacitor from becoming unexpectedly higher than the voltage command in the current stagnation state, prevent the smoothing capacitor from being damaged by an overvoltage and prevent excessive torque from being output from motors.
    Type: Grant
    Filed: May 22, 2007
    Date of Patent: May 1, 2012
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Masaki Okamura, Kiyotaka Matsubara, Shungo Tamura, Hiroki Ohtani, Hideo Nakai
  • Patent number: 8164282
    Abstract: An object of the present invention is to provide a motive power output apparatus including a motor with a permanent magnet and a motor without a permanent magnet. A boost device (10) is connected to a power storage device (B). A first drive device (30) is connected to the boost device (10). A first rotating electric machine (35) with a permanent magnet is connected to the first drive device (30). A second drive device (40) is connected to the power storage device (B). A second rotating electric machine (45) without a permanent magnet is connected to the second drive device (40). A third drive device (20) is connected in parallel to the first drive device (30). A third rotating electric machine (25) with a permanent magnet is connected to the third drive device (20). The second rotating electric machine (45) is formed of a reluctance motor or an induction motor. The first rotating electric machine (35) and the second rotating electric machine (45) of the present invention may be linked to wheels of a vehicle.
    Type: Grant
    Filed: May 22, 2007
    Date of Patent: April 24, 2012
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Masaki Okamura
  • Publication number: 20120081045
    Abstract: In a voltage conversion device of a motor drive control device, switching-control is performed so as to enlarge an output allowable voltage range of the voltage conversion device restricted by a dead time in a switching operation for an upper arm and a lower arm performing power conversion by a switching operation. Accordingly, restriction in the output voltage from the voltage conversion device, caused by the dead time, can be suppressed.
    Type: Application
    Filed: June 2, 2009
    Publication date: April 5, 2012
    Applicants: KABUSHIKI KAISHA TOYOTA JIDOSHOKKI, TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Naoyoshi Takamatsu, Masaki Okamura, Yasuhiro Koike
  • Publication number: 20120068646
    Abstract: A voltage control operation unit receives, from a subtraction unit, a value obtained by subtracting a detection value of a voltage from a voltage command value, and performs a control operation for setting the voltage to be equal to the voltage command value. The voltage control operation unit outputs the calculated control amount as a current command value. A current control operation unit receives, from a subtraction unit, a value obtained by subtracting a detection value of a current from a current command value, and performs a control operation for setting the current to be equal to the current command value. A driving signal generation unit generates a signal for driving a boost converter based on a duty command value received from the current control operation unit.
    Type: Application
    Filed: May 27, 2009
    Publication date: March 22, 2012
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Naoyoshi Takamatsu, Masaki Okamura, Daigo Nobe
  • Publication number: 20120056569
    Abstract: A control device for performing PWM control of an inverter includes a synchronous PWM control circuit for generating a control command for the inverter by performing PWM control based on a comparison between a sinusoidal voltage command signal for operating the AC motor according to an operation command and a carrier signal, and a carrier generating unit for keeping an integer as a synchronization number being a frequency ratio between the voltage command signal and the carrier signal, and producing the carrier signal by switching the synchronization number according to an operation state of the AC motor. The carrier generating unit adjusts a phase relationship between the voltage command signal and the carrier signal according to the synchronization number such that an AC current transmitted between the inverter and the AC motor according to the control command provided from the synchronous PWM control circuit is symmetrical with respect to a boundary between positive and negative portions.
    Type: Application
    Filed: May 29, 2009
    Publication date: March 8, 2012
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Naoyoshi Takamatsu, Masaki Okamura, Takanori Degaki
  • Publication number: 20120049774
    Abstract: In a converter of a motor drive control device, one of a first switching element and a second switching element is selected in accordance with a current command value of a current flowing through a reactor. The converter is then controlled so that a drive command for the selected switching element is generated. In this way, the efficiency of the converter is improved while a voltage step-up or step-down operation is performed by the converter.
    Type: Application
    Filed: May 27, 2009
    Publication date: March 1, 2012
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Naoyoshi Takamatsu, Masaki Okamura
  • Publication number: 20120019176
    Abstract: If it is determined that excess power is generated based on overcharge information of a power storage device, a controller starts an operation of consuming the excess power by an excessive power consuming circuit. The controller counts elapsed time from the time point when the power consuming operation started, and if the counted elapsed time exceeds a minimum on-time set in advance, switches the excessive power consuming circuit from active to inactive state. The minimum on-time is set based on a pattern that is expected to cause generation of excessive regenerative power from an AC electric motor because of abrupt change in running status of an electric powered vehicle mounting a motor drive system.
    Type: Application
    Filed: February 9, 2009
    Publication date: January 26, 2012
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventor: Masaki Okamura
  • Patent number: 8093843
    Abstract: By the vehicle controller of the present invention, when the economy mode is selected by a driver, boosting by a converter is limited and output torque of a motor is limited. Even in the economy mode, however, if the driver requests large torque, either the limit on boosting or the limit on output torque is cancelled. As a result, a vehicle controller for a vehicle including a battery, a converter boosting/lowering the battery voltage and a motor operating with the power from the converter is provided, by which unnecessary power consumption is reduced and the torque requested by the driver can be generated.
    Type: Grant
    Filed: May 19, 2008
    Date of Patent: January 10, 2012
    Assignees: Toyota Jidosha Kabushiki Kaisha, Aisin Aw Co., Ltd.
    Inventors: Masaki Okamura, Hideto Hanada, Masayoshi Suhama, Yuki Sugiyama, Ken Iwatsuki
  • Patent number: 8082073
    Abstract: A loss reduction module of an electric vehicle control device has a function to limit a torque to not exceed a constant loss characteristic and issue a torque instruction if a requested torque exceeds the constant loss characteristic when an ecology switch is turned ON and low fuel consumption travel is instructed. More specifically, when a requested torque exceeding the constant loss characteristic is input, a torque limit is applied to a point on the constant loss characteristic. Accordingly, the torque instruction is output as a torque which is suppressed more than a characteristic curve obtained by combining the constant loss characteristic and a characteristic indicating the relationship between the torque and the number of rotations during normal travel.
    Type: Grant
    Filed: January 23, 2008
    Date of Patent: December 20, 2011
    Assignees: Toyota Jidosha Kabushiki Kaisha, Aisin AW Co., Ltd.
    Inventors: Masaki Okamura, Masayoshi Suhama, Ken Iwatsuki
  • Publication number: 20110288706
    Abstract: An electric vehicle includes a synchronous motor that outputs torque to a first driving wheel; an induction motor that outputs torque to a second driving wheel; and an output torque changing portion that makes the synchronous motor torque smaller than the induction motor torque when torque is output to the first or second driving wheel and the vehicle speed is close to zero, and makes the synchronous motor torque larger than the induction motor torque when torque is output to the first or second driving wheel and the vehicle is moving at or greater than a predetermined speed in a direction opposite a direction in which the vehicle is being operated to move, by the torque output to the first and second driving wheels.
    Type: Application
    Filed: May 20, 2011
    Publication date: November 24, 2011
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventor: Masaki OKAMURA
  • Publication number: 20110282530
    Abstract: When an electric vehicle outputs a torque instruction, firstly, a request torque is acquired and a judged whether the acquired request torque is positive or negative. Regardless of the sign of the request torque, it is judged whether the eco-switch is ON. If the request torque has a positive sign and the eco-switch is OFF, a map A is selected. If the eco-switch is ON, a map B which limits the maximum torque to a low value for the map A is selected. If the request torque has a negative sign, a map C is selected regardless of the eco-switch ON/OFF state and the maximum torque is not limited.
    Type: Application
    Filed: June 30, 2011
    Publication date: November 17, 2011
    Applicants: AISIN AW CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Masayoshi Suhama, Hideto Hanada, Masaki Okamura, Hiroaki Kioka, Ken Iwatsuki
  • Patent number: 8040083
    Abstract: In a motor drive control system configured to include a converter capable of stepping up the voltage, when the locked state of MG2 operating as an electric motor does not occur (NO in S130), a voltage command value VHref for the converter output voltage is set according to respective required voltages of MG1 operating as an electric generator and MG2 (S140). In contrast, when the locked state of MG2 occurs (YES in S130), the voltage command value VHref is set to a limit voltage Vlmt or less for limiting the voltage step-up by the converter (S150, S180). When the locked state occurs, the converter output voltage is decreased and accordingly the DC voltage switched by the inverter is lowered, so that a switching loss at the switching device forming a part of the inverter is reduced and the temperature increase due to the heat generation can be suppressed.
    Type: Grant
    Filed: March 16, 2007
    Date of Patent: October 18, 2011
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Masaki Okamura, Hideaki Yaguchi
  • Patent number: 8018195
    Abstract: An AC motor drive control device includes a control mode judgment unit that performs a judgment based on required voltage amplitude required by a synchronous AC motor, in order to switch units for applying voltage to the AC motor to one of a rectangular wave voltage phase control unit, an overmodulation control unit, and a PWM current control unit.
    Type: Grant
    Filed: March 27, 2007
    Date of Patent: September 13, 2011
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Hiroki Ohtani, Makoto Nakamura, Kenji Yamada, Masaki Okamura, Hideto Hanada
  • Patent number: 7973505
    Abstract: When an electric vehicle outputs a torque instruction, firstly, a request torque is acquired and a judged whether the acquired request torque is positive or negative (S10) Regardless of the sign of the request torque, it is judged whether the eco-switch is ON (S12, S14) If the request torque has a positive sign and the eco-switch is OFF, a map A is selected (S20). If the eco-switch is ON, a map B which limits the maximum torque to a low value for the map A is selected (S22). If the request torque has a negative sign, a map C is selected regardless of the eco-switch ON/OFF state and the maximum torque is not limited (S24).
    Type: Grant
    Filed: January 31, 2008
    Date of Patent: July 5, 2011
    Assignees: Toyota Jidosha Kabushiki Kaisha, Aisin Aw Co., Ltd.
    Inventors: Masayoshi Suhama, Hideto Hanada, Masaki Okamura, Hiroaki Kioka, Ken Iwatsuki
  • Publication number: 20110127937
    Abstract: A triangle wave generator (4) measures the phase difference between a triangle wave (CA) and the rotor electrical angle (?m) during a first cycle in which the rotation rate of a rotor (7) is detected, and changes the frequency of the triangle wave (CA) when the value of the phase difference between the triangle wave (CA) and the rotor electrical angle (?m) exceeds a threshold value, thereby allowing rapid response to changes in rotor rotation when PWM control is performed.
    Type: Application
    Filed: October 1, 2009
    Publication date: June 2, 2011
    Applicant: Toyota Jidosha Kabushiki Kaisha
    Inventors: Naoyoshi Takamatsu, Masaki Okamura