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).
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Patent number: 7923961Abstract: A vehicle includes a motor for driving wheels WH, an inverter to drive the motor, and a control device to perform PWM control of the inverter. The control device performs synchronous PWM control in a case where an electric current supplied to the motor by the inverter or torque generated in the motor is larger than a threshold value; and performs the synchronous PWM control or non-synchronous PWM control in a case where the electric current or the torque is smaller than the threshold value and sets carrier frequency or a pulse number of the PWM control to be higher than the case where the electric current or the torque is larger than the threshold value. Thereby, it is possible to provide a vehicle of achieving reduction of noise, reduction of cost and improvement of fuel consumption in a balanced manner.Type: GrantFiled: July 22, 2009Date of Patent: April 12, 2011Assignee: Toyota Jidosha Kabushiki KaishaInventors: Naoyoshi Takamatsu, Masaki Okamura
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Patent number: 7898208Abstract: A boost converter boosts a DC voltage of a DC power supply. An inverter converts the output voltage of the boost converter into an AC voltage. A control device that controls the boost converter reduces an output voltage instruction value of the boost converter when the rotation speed of the AC motor decreases and an absolute value of a variation rate of the rotation speed is not less than a predetermined value. The inverter is controlled in the control mode selected from a plurality of control modes including three modes of a sine wave PWM control mode, an overmodulation PWM control mode and a rectangular wave control mode. The control device of the boost converter reduces the output voltage instruction value of the boost converter only when the control mode of the inverter is the rectangular wave control mode or the overmodulation control mode.Type: GrantFiled: November 1, 2006Date of Patent: March 1, 2011Assignee: Toyota Jidosha Kabushiki KaishaInventors: Kiyoe Ochiai, Masaki Okamura, Hiroyuki Oyanagi
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Patent number: 7893637Abstract: In a drive system of an AC motor in which a motor current is feedback-controlled, a motor current command is produced in a normal operation according to a torque command value on an optimum efficiency characteristic line so as to select an optimum current phase maximizing an output torque with a constant motor current amplitude. Conversely, when the AC motor produces an excessively generated power exceeding a regeneratable power quantity of the AC motor, a consuming operation is performed for intentionally increasing the power loss in the AC motor. In the consuming operation, the motor current command is produced according to the torque command value on a loss increase characteristic line to change the current phase from the above optimum value. Thereby, the power loss in the AC motor can be increased to consume the surplus power without causing instability in the motor control.Type: GrantFiled: October 26, 2006Date of Patent: February 22, 2011Assignee: Toyota Jidosha Kabushiki KaishaInventors: Masayoshi Suhama, Masaki Okamura, Eiji Sato
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Publication number: 20110006723Abstract: 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: ApplicationFiled: December 19, 2008Publication date: January 13, 2011Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Toshifumi Yamakawa, Hideto Hanada, Kazuhito Hayashi, Masayoshi Suhama, Masaki Okamura
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Patent number: 7869233Abstract: A control device calculates a voltage command value of a voltage step-up converter based on a torque command value and a motor revolution number and calculates an on-duty of an NPN transistor based on the calculated voltage command value and a DC voltage from a voltage sensor. When the on-duty is influenced by a dead time of NPN transistors, control device fixes the on-duty at 1.0 to control the NPN transistors in such a manner that the voltage is increased or decreased.Type: GrantFiled: July 12, 2004Date of Patent: January 11, 2011Assignees: Toyota Jidosha Kabushiki Kaisha, Denso CorporationInventors: Masaki Okamura, Takashi Yamashita
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Patent number: 7868567Abstract: An object of the invention is to limit a current flowing in a booster converter circuit for a vehicle within a predetermined range. In the booster converter circuit for a vehicle including a battery that outputs a DC voltage; a switching unit having a switching element to be controlled to ON or OFF; an inductive element unit being connected between the battery and the switching unit and including an inductive element; a switching control unit that controls the switching element, an output voltage measuring unit that measures an output voltage of the booster converter circuit for a vehicle is provided, and the duty ratio determining device obtains a control duty ratio with respect to the switching element on the basis of a measured output voltage value so that a value of a converter current flowing through a path from the battery to the switching unit falls within a predetermined range.Type: GrantFiled: November 18, 2008Date of Patent: January 11, 2011Assignee: Toyota Jidosha Kabushiki KaishaInventor: Masaki Okamura
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Publication number: 20100231151Abstract: 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: ApplicationFiled: March 27, 2007Publication date: September 16, 2010Inventors: Hiroki Ohtani, Makoto Nakamura, Kenji Yamada, Masaki Okamura, Hideto Hanada
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Patent number: 7782037Abstract: A desired current is caused to flow through a coil by controlling switching of switching elements by a PWM controller. For a voltage sensor, a value of Vo??V, which is a difference between a midpoint voltage Vo of the switching elements and a predetermined threshold voltage ?V, and a value of Vo?(Vc??V), which is a difference between the midpoint voltage Vo and a value obtained by subtracting the threshold voltage ?V from a voltage Vc of an upper line, are determined. Then, the determined results obtained from the voltage sensor are input to the PWM controller through flip-flops and a dead time compensator to compensate for dead time, such as, for example, for a command for PWM control signal generation.Type: GrantFiled: August 2, 2007Date of Patent: August 24, 2010Assignee: Toyota Jidosha Kabushiki KaishaInventors: Hiroki Ohtani, Masaki Okamura
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Publication number: 20100185350Abstract: A carrier frequency setting unit (64) sets a carrier frequency (FC) according to the torque command (TR) of a motor generator and the number of motor rotations (MRN). A PWM signal generation unit (68) generates phase modulation waves corresponding to respective phase voltage commands (Vu, Vv, Vw) and generates phase PWM signals (Pu, Pv, Pw) according to the magnitude relationship between each of the phase modulation waves and a carrier wave having the carrier frequency (FC). A PWM center control unit (66), when the carrier frequency (FC) is lower than a predetermined frequency, generates a PWM center correction value (?CE) for variably controlling a PWM center and outputs to the PWM signal generation unit (68).Type: ApplicationFiled: December 22, 2008Publication date: July 22, 2010Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Masaki Okamura, Natsuki Nozawa, Hideto Hanada
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Patent number: 7723945Abstract: A square wave voltage having an amplitude equal to an output voltage of a converter is applied to an AC motor by a square wave control block. Torque control of the AC motor is performed basically by changing the voltage phase of the square wave voltage according to the torque deviation. When the motor revolution is suddenly changed, a instruction value correction unit sets a voltage instruction value of the output voltage of the converter according to a change ratio of the motor revolutions. This improves control of the motor current by changing the voltage applied to the motor in accordance with the sudden change of the motor revolutions without waiting for torque feedback control having a low control response.Type: GrantFiled: May 1, 2006Date of Patent: May 25, 2010Assignee: Toyota Jidosha Kabushiki KaishaInventor: Masaki Okamura
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Patent number: 7701156Abstract: A voltage command value of a converter is set by executing the step of determining a candidate voltage of a system voltage VH as a converter output voltage in a voltage range from the minimum necessary voltage corresponding to induction voltage of a motor generator and a maximum output voltage of the converter; the step of estimating power loss at the battery, converter, inverter and motor generator, at each candidate voltage, and calculating total sum of estimated power loss of the overall system; and the step of setting the voltage command value VH# based on the candidate voltage that minimizes the total sum of estimated power losses among the candidate voltages.Type: GrantFiled: May 23, 2007Date of Patent: April 20, 2010Assignee: Toyota Jidosha Kabushiki KaishaInventor: Masaki Okamura
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Patent number: 7692940Abstract: A voltage transformer, which is placed between a DC power source (B) and a motor (M1), includes: a voltage sensor (10) and an electric current sensor (11), which senses input and output of electric power to and from the DC power source (B); a buck-boost converter (12) having power control elements, which is placed in a path connecting between power lines (PL1) and (PL2) that establish the connection to the DC power source (B) and the connection to the motor (M1), respectively; and a controller (30) for controlling the buck-boost converter (12). The controller (30) monitors the change in the regenerated power that is supplied to the DC power source (B), based on the outputs from the voltage sensor (10) and the electric current sensor (11), and, if the amount of change in the regenerated power is greater than a predetermined amount, the controller (30) changes the operation mode of the buck-boost converter (12) from a rapid operation mode to a slow operation mode.Type: GrantFiled: December 14, 2006Date of Patent: April 6, 2010Assignee: Toyota Jidosha Kabushiki KaishaInventors: Kiyoe Ochiai, Masaki Okamura, Sojiro Yokoyama
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Publication number: 20100052583Abstract: A vehicle includes a motor for driving wheels WH, an inverter to drive the motor, and a control device to perform PWM control of the inverter. The control device performs synchronous PWM control in a case where an electric current supplied to the motor by the inverter or torque generated in the motor is larger than a threshold value; and performs the synchronous PWM control or non-synchronous PWM control in a case where the electric current or the torque is smaller than the threshold value and sets carrier frequency or a pulse number of the PWM control to be higher than the case where the electric current or the torque is larger than the threshold value. Thereby, it is possible to provide a vehicle of achieving reduction of noise, reduction of cost and improvement of fuel consumption in a balanced manner.Type: ApplicationFiled: July 22, 2009Publication date: March 4, 2010Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Naoyoshi Takamatsu, Masaki Okamura
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Publication number: 20100052588Abstract: 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: ApplicationFiled: May 19, 2008Publication date: March 4, 2010Applicants: Toyota Jidosha Kabushiki Kaisha, Aisin AW Co., Ltd.Inventors: Masaki Okamura, Hideto Hanada, Masayoshi Suhama, Yuki Sugiyama, Ken Iwatsuki
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Publication number: 20100045224Abstract: 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: ApplicationFiled: January 31, 2008Publication date: February 25, 2010Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, AISIN AW CO., LTDInventors: Masayoshi Suhama, Hideto Hanada, Masaki Okamura, Hiroaki Kioka, Ken Iwatsuki
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Patent number: 7656690Abstract: A control device calculates a voltage command value of a voltage step-up converter based on a torque command value and a motor revolution number and calculates the on-duty of an NPN transistor based on the calculated voltage command value and a DC voltage from a voltage sensor. Under the conditions that the on-duty is influenced by a dead time and the DC voltage is smaller than a predetermined set value, the control device controls NPN transistors to step-up or step-down the voltage while fixing the on-duty at 1.0.Type: GrantFiled: November 16, 2005Date of Patent: February 2, 2010Assignee: Toyota Jidosha Kabushiki KaishaInventors: Kenji Yamada, Eiji Sato, Masaki Okamura
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Publication number: 20090314564Abstract: A power output apparatus including a power source, an electric motor and a connecting and disconnecting device, and a method of controlling the power output apparatus, are provided. When load driving force is applied from the power source to a power shaft in a condition where the power shaft and a driveshaft are disconnected from each other by the connecting and disconnecting device, lock control is executed to control the motor by fixing a direction of a magnetic field of a stator so as to restrict rotation of a rotor. When the rotor rotates during execution of the lock control, rotation retardation control is executed to control the motor by rotating the direction of the stator magnetic field in accordance with rotation of the rotor, so that driving force is applied from the motor to the power shaft in a direction opposite to that of the load driving force as driving force applied from the power source to the power shaft.Type: ApplicationFiled: June 18, 2009Publication date: December 24, 2009Applicant: Toyota Jidosha Kabushiki KaishaInventors: Masaki Okamura, Kazuhito Hayashi
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Publication number: 20090302818Abstract: 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: ApplicationFiled: May 22, 2007Publication date: December 10, 2009Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Masaki Okamura, Kiyotaka Matsubara, Shungo Tamura, Hiroki Ohtani, Hideo Nakai
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Publication number: 20090243522Abstract: In a drive system of an AC motor in which a motor current is feedback-controlled, a motor current command is produced in a normal operation according to a torque command value on an optimum efficiency characteristic line so as to select an optimum current phase maximizing an output torque with a constant motor current amplitude. Conversely, when the AC motor produces an excessively generated power exceeding a regeneratable power quantity of the AC motor, a consuming operation is performed for intentionally increasing the power loss in the AC motor. In the consuming operation, the motor current command is produced according to the torque command value on a loss increase characteristic line to change the current phase from the above optimum value. Thereby, the power loss in the AC motor can be increased to consume the surplus power without causing instability in the motor control.Type: ApplicationFiled: October 26, 2006Publication date: October 1, 2009Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Masayoshi Suhama, Masaki Okamura, Eiji Sato
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Publication number: 20090248229Abstract: 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: ApplicationFiled: January 23, 2008Publication date: October 1, 2009Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, AISIN AW CO., LTDInventors: Masaki Okamura, Masayoshi Suhama, Ken Iwatsuki