Patents by Inventor Atsuo Kawamura
Atsuo Kawamura 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: 10581338Abstract: A power supply system includes a plurality of AC output converters connected in parallel for supplying electric power to an AC load. Each of the plurality of AC output converters includes an output impedance connected to the AC load, a PWM converter configured to convert DC power into AC power, and a controller configured to output a voltage command value to the PWM converter. The controller includes a vector adder configured to perform vector addition of a part of a voltage drop occurring due to a current flowing through the output impedance and a voltage command value of the AC load, and a converter configured to output a voltage command value to the PWM converter based on a vector sum obtained through the vector addition.Type: GrantFiled: September 14, 2016Date of Patent: March 3, 2020Assignees: National University Corporation YOKOHAMA National University, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Atsuo Kawamura, Mohammad Bani Shamseh, Teruo Yoshino
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Publication number: 20190214918Abstract: A power supply system includes a plurality of AC output converters connected in parallel for supplying electric power to an AC load. Each of the plurality of AC output converters includes an output impedance connected to the AC load, a PWM converter configured to convert DC power into AC power, and a controller configured to output a voltage command value to the PWM converter. The controller includes a vector adder configured to perform vector addition of a part of a voltage drop occurring due to a current flowing through the output impedance and a voltage command value of the AC load, and a converter configured to output a voltage command value to the PWM converter based on a vector sum obtained through the vector addition.Type: ApplicationFiled: September 14, 2016Publication date: July 11, 2019Applicants: National University Corporation YOKOHAMA National University, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Atsuo KAWAMURA, Mohammad Bani SHAMSEH, Teruo YOSHINO
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Patent number: 9985530Abstract: A soft switching system DC-DC converter includes a switching element, a transformer or a reactor, and a controller configured to control a switching operation of the switching element; and carries out the switching operation of the switching element in a state that a voltage or a current to be applied to the switching element is zero. In a case where a required output value of the DC-DC converter is lower than the minimum output over which soft switching is established, the controller controls the operation of the switching element so that an operation period in which an output of the DC-DC converter becomes the minimum output or higher and a stop period in which the output becomes zero are alternately repeated.Type: GrantFiled: March 27, 2014Date of Patent: May 29, 2018Assignee: Nissan Motor Co., Ltd.Inventors: Kensuke Sasaki, Daiki Tanaka, Yuichi Shibukawa, Atsuo Kawamura, Kohei Aoyama
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Patent number: 9559620Abstract: A power supply device has a first power supply capable of storing and discharging electric power, a second power supply connected in series to the first power supply and capable of storing and discharging the electric power, an isolated DC-DC converter including a primary side terminal to which the first power supply is connected, and a secondary side terminal to which the second power supply is connected, and a power supply control unit that controls a voltage of the second power supply using the isolated DC-DC converter. A direct-current voltage outputted from the first power supply and the second power supply connected in series is inputted to a first inverter, converted into an alternating-current voltage by the first inverter, and then supplied to a vehicle drive motor.Type: GrantFiled: February 22, 2013Date of Patent: January 31, 2017Assignees: Nissan Motor Co., Ltd.Inventors: Yusuke Zushi, Takashi Fukushige, Yuichi Shibukawa, Kensuke Sasaki, Atsuo Kawamura
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Publication number: 20160094133Abstract: A soft switching system DC-DC converter includes a switching element, a transformer or a reactor, and a controller configured to control a switching operation of the switching element; and carries out the switching operation of the switching element in a state that a voltage or a current to be applied to the switching element is zero. In a case where a required output value of the DC-DC converter is lower than the minimum output over which soft switching is established, the controller controls the operation of the switching element so that an operation period in which an output of the DC-DC converter becomes the minimum output or higher and a stop period in which the output becomes zero are alternately repeated.Type: ApplicationFiled: March 27, 2014Publication date: March 31, 2016Inventors: Kensuke SASAKI, Daiki TANAKA, Yuichi SHIBUKAWA, Atsuo KAWAMURA, Kohei AOYAMA
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Patent number: 9029030Abstract: A voltage boost converter includes: a main voltage boost portion that has a first switch and a first coil, and that raises output voltage of a direct-current power source by using counter electromotive force of the coil caused by the switch performing a switching action on the coil; and a subsidiary voltage boost portion which has a capacitor that adjusts potential difference between two poles of the switch by amount of electricity stored, and which reduces switching loss of the switch by adjusting the amount of electricity in the capacitor during the switching action, and which has a second switch and a second coil. The second coil is formed by winding a wire around at least a portion of a core formed of a magnetic body. The core is provided with a gap formed of a non-magnetic body. A core region formed of a magnetic body is adjacent to the gap.Type: GrantFiled: December 16, 2010Date of Patent: May 12, 2015Assignees: Toyota Jidosha Kabushiki Kaisha, National University Corporation Yokohama National UniversityInventors: Hiroyuki Imanishi, Kota Manabe, Nobuyuki Kitamura, Takahiko Hasegawa, Atsuo Kawamura, Yukinori Tsuruta
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Publication number: 20150002057Abstract: A power supply device has a first power supply capable of storing and discharging electric power, a second power supply connected in series to the first power supply and capable of storing and discharging the electric power, an isolated DC-DC converter including a primary side terminal to which the first power supply is connected, and a secondary side terminal to which the second power supply is connected, and a power supply control unit that controls a voltage of the second power supply using the isolated DC-DC converter. A direct-current voltage outputted from the first power supply and the second power supply connected in series is inputted to a first inverter, converted into an alternating-current voltage by the first inverter, and then supplied to a vehicle drive motor.Type: ApplicationFiled: February 22, 2013Publication date: January 1, 2015Applicant: Nissan Motor Co., Ltd.Inventors: Yusuke Zushi, Takashi Fukushige, Yuichi Shibukawa, Kensuke Sasaki, Atsuo Kawamura
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Publication number: 20120295174Abstract: A voltage boost converter includes: a main voltage boost portion that has a first switch and a first coil, and that raises output voltage of a direct-current power source by using counter electromotive force of the coil caused by the switch performing a switching action on the coil; and a subsidiary voltage boost portion which has a capacitor that adjusts potential difference between two poles of the switch by amount of electricity stored, and which reduces switching loss of the switch by adjusting the amount of electricity in the capacitor during the switching action, and which has a second switch and a second coil. The second coil is formed by winding a wire around at least a portion of a core formed of a magnetic body. The core is provided with a gap formed of a non-magnetic body. A core region formed of a magnetic body is adjacent to the gap.Type: ApplicationFiled: December 16, 2010Publication date: November 22, 2012Applicants: National University Corporation Yokohama National University, Toyota Jidosha Kabushiki KaishaInventors: Hiroyuki Imanishi, Kota Manabe, Nobuyuki Kitamura, Takahiko Hasegawa, Atsuo Kawamura, Yukinori Tsuruta
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Patent number: 6897633Abstract: A stepping motor driver which drives a stepping motor for position and speed control. The stepping motor driver comprises: a current control means which outputs values corresponding to applied voltages; current sensors which detect phase currents; and a magnetic pole position estimation unit which uses the values corresponding to applied voltages and detected phase current values as outputs of the current sensors to obtain a magnetic pole position estimate. The magnetic pole position estimation unit calculates a magnetic pole position estimate from speed electromotive force estimates or from differences between phase currents at zero speed and detected phase current values.Type: GrantFiled: March 9, 2004Date of Patent: May 24, 2005Assignee: Japan Servo Co., Ltd.Inventors: Yoshifumi Kuwano, Akio Takemori, Hiroaki Taka, Yasuo Matsuda, Yoshihiro Okumatsu, Atsuo Kawamura, Yukinari Takahashi
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Patent number: 6850027Abstract: The stepping motor driver comprises an inverter for feeding stepped currents to windings of a stepping motor, a position detector for obtaining a detected angle of a rotor of the stepping motor and a current controller for controlling the inverter. In a d-q rotational coordinate system in which the d-axis is in the direction of the magnetic flux of the rotor and the q-axis is in the direction perpendicular to the d-axis, an excitation angle for a winding is determined from a d-axis component and a q-axis component of a command current to the winding, a lead angle control signal is computed from the excitation angle, and a phase of an applied voltage to the stepping motor is controlled using the lead angle control signal.Type: GrantFiled: March 18, 2003Date of Patent: February 1, 2005Assignee: Japan Servo Co., Ltd.Inventors: Yoshifumi Kuwano, Akio Takemori, Yasuo Matsuda, Yoshihiro Okumatsu, Atsuo Kawamura
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Publication number: 20040178763Abstract: A stepping motor driver which drives a stepping motor for position and speed control. The stepping motor driver comprises: a current control means which outputs values corresponding to applied voltages; current sensors which detect phase currents; and a magnetic pole position estimation unit which uses the values corresponding to applied voltages and detected phase current values as outputs of the current sensors to obtain a magnetic pole position estimate. The magnetic pole position estimation unit calculates a magnetic pole position estimate from speed electromotive force estimates or from differences between phase currents at zero speed and detected phase current values.Type: ApplicationFiled: March 9, 2004Publication date: September 16, 2004Inventors: Yoshifumi Kuwano, Akio Takemori, Hiroaki Taka, Yasuo Matsuda, Yoshihiro Okumatsu, Atsuo Kawamura, Yukinari Takahashi
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Publication number: 20030178965Abstract: The stepping motor driver comprises an inverter for feeding stepped currents to windings of a stepping motor, a position detector for obtaining a detected angle of a rotor of the stepping motor and a current controller for controlling the inverter. In a d-q rotational coordinate system in which the d-axis is in the direction of the magnetic flux of the rotor and the q-axis is in the direction perpendicular to the d-axis, an excitation angle for a winding is determined from a d-axis component and a q-axis component of a command current to the winding, a lead angle control signal is computed from the excitation angle, and a phase of an applied voltage to the stepping motor is controlled using the lead angle control signal.Type: ApplicationFiled: March 18, 2003Publication date: September 25, 2003Inventors: Yoshifumi Kuwano, Akio Takemori, Yasuo Matsuda, Yoshihiro Okumatsu, Atsuo Kawamura