Patents by Inventor Mitsujiro Sawamura
Mitsujiro Sawamura 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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Publication number: 20190149068Abstract: A motor controller includes an AC-to-DC converter that converts AC power from an AC power source into DC power and supplies the DC power to a DC bus line, an auxiliary power source that charges the DC bus line with the DC power and discharges the DC power from the DC bus line, and a first inverter that controls power supply to a motor using the DC power from the DC bus line. The auxiliary power source includes a rotating electrical machine, a flywheel connected to the machine, a second inverter that supplies power to the machine using the DC power on the DC bus line and regenerates the power from the machine into the DC power on the DC bus line, and control circuitry that controls the second inverter to cause rotational angle velocity of the flywheel to keep positive correlation with bus-to-bus voltage of the DC bus line.Type: ApplicationFiled: May 31, 2018Publication date: May 16, 2019Applicant: KABUSHIKI KAISHA YASKAWA DENKIInventors: Mitsujiro SAWAMURA, Shouta KAWAHARA, Tatsuaki WADA
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Patent number: 10158316Abstract: A motor control apparatus includes an AC-DC converter, an auxiliary power source, and an inverter. The AC-DC converter converts AC power into DC power and feeds the DC power to a DC bus bar. DC power is fed from the auxiliary power source to the DC bus bar and from the DC bus bar to the auxiliary power source. The inverter converts the DC power of the DC bus bar into the AC power and feeds the AC power to a motor. The auxiliary power source includes a capacitor, a DC-DC converter, and circuitry. The DC-DC converter performs conversion between a first DC voltage of the DC bus bar and a second DC voltage applied between both terminals of the capacitor or inside of the capacitor. The circuitry is configured to control the DC-DC converter to maintain positive correlation between the second DC voltage and the first DC voltage.Type: GrantFiled: February 10, 2017Date of Patent: December 18, 2018Assignee: KABUSHIKI KAISHA YASKAWA DENKIInventors: Mitsujiro Sawamura, Yasuhiko Kaku
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Patent number: 10110155Abstract: A motor control apparatus includes an AC-DC converter, an auxiliary power source, and an inverter. The AC-DC converter converts AC power into DC power and feeds the DC power to a DC bus bar. DC power is fed from the auxiliary power source to the DC bus bar and from the DC bus bar to the auxiliary power source. The inverter converts the DC power of the DC bus bar into the AC power and feeds the AC power to a motor. The auxiliary power source includes a capacitor, a DC-DC converter, and circuitry. The DC-DC converter performs conversion between a first DC voltage of the DC bus bar and a second DC voltage applied between both terminals of the capacitor or inside of the capacitor. The circuitry is configured to control the DC-DC converter to maintain positive correlation between the second DC voltage and the first DC voltage.Type: GrantFiled: February 10, 2017Date of Patent: October 23, 2018Assignee: KABUSHIKI KAISHA YASKAWA DENKIInventors: Mitsujiro Sawamura, Yasuhiko Kaku
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Patent number: 10050578Abstract: A motor control system includes a DC-to-DC converter including a semiconductor switch and a reactor that cooperates with the switch to convert input-side DC bus voltage across first and second input-side DC buses into predetermined output-side DC bus voltage across first and second output-side DC buses and to output the output-side voltage, control circuitry that controls duty factor of the switch and determine, based on input-side detection value of the input-side voltage and output-side detection value of the output-side voltage, whether there is failure in the system when the factor is 100 percent and reactor-current detection value of reactor current through the reactor is approximately zero, a smoothing capacitor connected to the output-side buses and disposed between the output-side buses, and an inverter that is connected to the capacitor through the output-side buses, converts DC power from the output-side buses into AC power and supplies the power to a motor.Type: GrantFiled: June 14, 2017Date of Patent: August 14, 2018Assignee: KABUSHIKI KAISHA YASKAWA DENKIInventors: Mitsujiro Sawamura, Kunimasa Ando, Tatsuaki Wada
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Publication number: 20180013373Abstract: A motor control system includes a DC-to-DC converter including a semiconductor switch and a reactor that cooperates with the switch to convert input-side DC bus voltage across first and second input-side DC buses into predetermined output-side DC bus voltage across first and second output-side DC buses and to output the output-side voltage, control circuitry that controls duty factor of the switch and determine, based on input-side detection value of the input-side voltage and output-side detection value of the output-side voltage, whether there is failure in the system when the factor is 100 percent and reactor-current detection value of reactor current through the reactor is approximately zero, a smoothing capacitor connected to the output-side buses and disposed between the output-side buses, and an inverter that is connected to the capacitor through the output-side buses, converts DC power from the output-side buses into AC power and supplies the power to a motor.Type: ApplicationFiled: June 14, 2017Publication date: January 11, 2018Applicant: Kabushiki Kaisha Yaskawa DenkiInventors: Mitsujiro SAWAMURA, Kunimasa Ando, Tatsuaki Wada
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Publication number: 20170229994Abstract: A motor control apparatus includes an AC-DC converter, an auxiliary power source, and an inverter. The AC-DC converter converts AC power into DC power and feeds the DC power to a DC bus bar. DC power is fed from the auxiliary power source to the DC bus bar and from the DC bus bar to the auxiliary power source. The inverter converts the DC power of the DC bus bar into the AC power and feeds the AC power to a motor. The auxiliary power source includes a capacitor, a DC-DC converter, and circuitry. The DC-DC converter performs conversion between a first DC voltage of the DC bus bar and a second DC voltage applied between both terminals of the capacitor or inside of the capacitor. The circuitry is configured to control the DC-DC converter to maintain positive correlation between the second DC voltage and the first DC voltage.Type: ApplicationFiled: February 10, 2017Publication date: August 10, 2017Applicant: KABUSHIKI KAISHA YASKAWA DENKIInventors: Mitsujiro SAWAMURA, Yasuhiko KAKU
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Patent number: 9537431Abstract: This disclosure discloses a brake diagnosis device configured to diagnose a brake of a motor with a brake. The brake diagnosis device includes a brake control part, a diagnosis part, and a signal output part. The brake control part is configured to actuate or release the brake. The diagnosis part is configured to diagnose a presence or absence of an abnormality of the brake while the brake is actuated by the brake control part. The signal output part is configured to output a signal related to a brake abnormality after the brake is released by the brake control part in a case that the diagnosis part diagnoses the brake as having an abnormality.Type: GrantFiled: November 25, 2015Date of Patent: January 3, 2017Assignee: KABUSHIKI KAISHA YASKAWA DENKIInventors: Mitsujiro Sawamura, Junichi Watanabe, Daichi Horimai
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Publication number: 20160156288Abstract: This disclosure discloses a brake diagnosis device configured to diagnose a brake of a motor with a brake. The brake diagnosis device includes a brake control part, a diagnosis part, and a signal output part. The brake control part is configured to actuate or release the brake. The diagnosis part is configured to diagnose a presence or absence of an abnormality of the brake while the brake is actuated by the brake control part. The signal output part is configured to output a signal related to a brake abnormality after the brake is released by the brake control part in a case that the diagnosis part diagnoses the brake as having an abnormality.Type: ApplicationFiled: November 25, 2015Publication date: June 2, 2016Applicant: KABUSHIKI KAISHA YASKAWA DENKIInventors: Mitsujiro SAWAMURA, Junichi WATANABE, Daichi HORIMAI
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Patent number: 8541962Abstract: A motor driving apparatus includes a motor driving unit, a low-voltage source, a current detecting element, and an insulation resistance degradation determinator. The motor driving unit includes an inverter coupled between a positive DC bus line and a negative DC bus line of a DC power source. The inverter converts DC power into AC power to drive an AC motor. The low-voltage source is coupled between a ground and at least one of the positive DC bus line and the negative DC bus line. The current detecting element detects a closed circuit current flowing through a closed circuit of the low-voltage source, the AC motor, and a part of the inverter. The insulation resistance degradation determinator makes a comparison between the closed circuit current and a predetermined threshold, and configured to determine, based on the comparison, whether an insulation resistance of the AC motor is degraded.Type: GrantFiled: November 16, 2011Date of Patent: September 24, 2013Assignee: Kabushiki Kaisha Yaskawa DenkiInventors: Kazuo Sato, Mitsujiro Sawamura
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Publication number: 20120217922Abstract: A motor driving apparatus includes a motor driving unit, a low-voltage source, a current detecting element, and an insulation resistance degradation determinator. The motor driving unit includes an inverter coupled between a positive DC bus line and a negative DC bus line of a DC power source. The inverter converts DC power into AC power to drive an AC motor. The low-voltage source is coupled between a ground and at least one of the positive DC bus line and the negative DC bus line. The current detecting element detects a closed circuit current flowing through a closed circuit of the low-voltage source, the AC motor, and a part of the inverter. The insulation resistance degradation determinator makes a comparison between the closed circuit current and a predetermined threshold, and configured to determine, based on the comparison, whether an insulation resistance of the AC motor is degraded.Type: ApplicationFiled: November 16, 2011Publication date: August 30, 2012Applicant: KABUSHIKI KAISHA YASKAWA DENKIInventors: Kazuo Sato, Mitsujiro Sawamura
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Patent number: 8189356Abstract: There is provided a PWM inverter capable of preventing a phase error from occurring in generating a PWM signal even in the case where a carrier wave frequency is not sufficiently higher than a signal wave frequency. A PWM signal generating section (2) includes a phase adjusting section (11) configured to advance a phase of the signal wave by adding, to a signal wave, a delay component of the PWM signal with respect to the signal wave, the phase delay component being involved by digital control. Furthermore, in a case where the carrier wave frequency is changed, the phase delay component with respect to the signal wave is updated in synchronism with the timing of change of the carrier wave frequency.Type: GrantFiled: March 6, 2007Date of Patent: May 29, 2012Assignee: Kabushiki Kaisha Yaskawa DenkiInventors: Hajime Takahashi, Mitsujiro Sawamura
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Patent number: 8120302Abstract: A servo control apparatus capable of suppressing adverse effects of disturbance, load variation and the like, and realizing robust and high-performance speed control. The apparatus includes both of the following observers: a disturbance observer for adding a disturbance compensation torque Tf, calculated from a torque command T* and an electric motor rotational speed ?m, to a torque command basic signal T0*, calculated on the basis of a deviation between a speed command ?* and a feedback speed ?f by a PI control section, thus outputting the torque command T*; and a phase advance compensation observer for generating, from the torque command basic signal T0* and the electric motor rotational speed ?m, an output of a nominal plant serving as an element in which no delay occurs, thus outputting the output as the feedback speed ?f.Type: GrantFiled: January 23, 2007Date of Patent: February 21, 2012Assignee: Kabushiki Kaisha Yaskawa DenkiInventors: Wennong Zhang, Mitsujiro Sawamura, Yasuyuki Takei
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Patent number: 7800338Abstract: A voltage type inverter apparatus comprising a voltage correcting portion. The voltage correcting portion corrects a given voltage instruction based on a value generated by passing a direct current bus voltage detected value through a first degree delay filter. In decelerating a speed of the alternating current motor, the speed is decelerated in an overexcited state by multiplying the given voltage instruction by a set gain. Simultaneously, a time constant of the first degree delay filter is made larger than a time constant in a normal control state.Type: GrantFiled: March 28, 2005Date of Patent: September 21, 2010Assignee: Kabushiki Kaisha Yaskawa DenkiInventors: Hideaki Iura, Kazuhiko Hiramatsu, Mitsujiro Sawamura
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Publication number: 20090243533Abstract: The present invention provides a servo control apparatus capable of suppressing adverse effects of disturbance, load variation and the like, and realizing robust and high-performance speed control. The apparatus includes both of the following observers: a disturbance observer (5) for adding a disturbance compensation torque Tf, calculated from a torque command T* and an electric motor rotational speed ?m, to a torque command basic signal T0*, calculated on the basis of a deviation between a speed command ?* and a feedback speed ?f by a PI control section (2), thus outputting the torque command T*; and a phase advance compensation observer (6) for generating, from the torque command basic signal T0* and the electric motor rotational speed ?m, an output of a nominal plant (61) serving as an element in which no delay occurs, thus outputting the output as the feedback speed ?f.Type: ApplicationFiled: January 23, 2007Publication date: October 1, 2009Applicant: KABUSHIKI KAISHA YASKAWA DENKIInventors: Wennong Zhang, Mitsujiro Sawamura, Yasuyuki Takei
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Publication number: 20090161393Abstract: There is provided a PWM inverter capable of preventing a phase error from occurring in generating a PWM signal even in the case where a carrier wave frequency is not sufficiently higher than a signal wave frequency. A PWM signal generating section (2) includes a phase adjusting section (11) configured to advance a phase of the signal wave by adding, to a signal wave, a delay component of the PWM signal with respect to the signal wave, the phase delay component being involved by digital control. Furthermore, in a case where the carrier wave frequency is changed, the phase delay component with respect to the signal wave is updated in synchronism with the timing of change of the carrier wave frequency.Type: ApplicationFiled: March 6, 2007Publication date: June 25, 2009Applicant: KABUSHIKI KAISHA YASKAWA DENKIInventors: Hajime Takahashi, Mitsujiro Sawamura
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Patent number: 7423395Abstract: It is the objective of the present invention to provide a sensorless vector control method and a control apparatus, for an alternating-current motor, that can smoothly restart an alternating-current motor in the free running state. According to the present invention, when a current that flows in an alternating-current motor (2) at a restart time 7 the alternating-current motor (2) continuously flows at a designated current level or higher for a designated period of time, it is determined that the rotational direction or the velocity of the alternating-current motor (2) is incorrectly estimated, and a direct current or a direct-current voltage is again applied to again estimate the rotational direction and the velocity.Type: GrantFiled: July 2, 2003Date of Patent: September 9, 2008Assignee: Kabushiki Kaisha Yaskawa DenkiInventors: Hideaki Iura, Kazuhiro Nonaka, Yuichi Terazono, Yoichi Yamamoto, Satoshi Sueshima, Katsushi Terazono, Mitsujiro Sawamura
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Patent number: 7348749Abstract: A control device is provided for a synchronous motor, which drives the synchronous motor through a voltage operated PWM inverter and controls a torque and a speed of the motor, including a unit for causing a PWM carrier signal to have an arbitrary phase difference between two phases such UV, VW, or WU in three phases of U, V, and W, a unit for extracting a high frequency voltage and a high frequency current, which are thus generated from a detecting voltage or a command voltage and a detecting current, and a unit for estimating a position of a magnetic flux or position of a magnetic pole by using the high frequency voltage and the high frequency current which are excited.Type: GrantFiled: August 25, 2003Date of Patent: March 25, 2008Assignee: Kabushiki Kaisha Yaskawa DenkiInventors: Kozo Ide, Mitsujiro Sawamura, Toshihiro Sawa, Jun Oyama
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Publication number: 20070216340Abstract: To be able to reduce a speed of an alternating current motor by an inverter apparatus by a time period as short as possible and to control an alternating current motor which is easy to be saturated magnetically by a previously set current or lower such that the inverter apparatus is not stopped by an overcurrent or the alternating current motor is not burned.Type: ApplicationFiled: March 28, 2005Publication date: September 20, 2007Inventors: Hideaki Iura, Kazuhito Hiramatsu, Mitsujiro Sawamura
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Publication number: 20070069682Abstract: It is an object of the invention to provide a control device for a synchronous motor which can detect the position of a magnetic pole from a zero speed without requiring a signal generator. The invention provides a control device for a synchronous motor which drives the synchronous motor through a voltage-operated PWM inverter and controls a torque and a speed of the motor, including means (6-3) for causing a PWM carrier signal to have an arbitrary phase difference between two phases such as UW, VW or WU in three phases of U, V and W, means (11) for extracting a high frequency voltage and a high frequency current which are thus generated from a detecting voltage or a command voltage and a detecting current, and means (12) for estimating a position of a magnetic flux or a position of a magnetic pole by using the high frequency voltage and the high frequency current which are extracted.Type: ApplicationFiled: August 25, 2003Publication date: March 29, 2007Inventors: Kozo Ide, Mitsujiro Sawamura, Toshihiro Sawa, Jun Oyama
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Patent number: 7157876Abstract: It is an object of the invention to provide an apparatus for estimating a magnetic pole position of a motor in which the amplitudes of high-frequency currents can be adjusted. In the invention, a controlling apparatus for driving a motor (1-1) by a voltage source PWM inverter (1-2), and controlling a torque and speed, or torque, speed, and position of the motor has: means for switching over first means for producing an arbitrary phase difference in PWM carrier signals between respective two phases such as UV, VW, or WU of three or UVW phases, and second means for causing the phase difference between two phases such as V, VW, or WU of three or UVW phases to become zero; means for extracting high-frequency currents in a same frequency band as carrier signals generated by it, from estimated currents; and means (1-4) for estimating a magnetic pole position by using the extracted high-frequency currents.Type: GrantFiled: September 25, 2003Date of Patent: January 2, 2007Assignee: Kabushiki Kaisha Yaskawa DenkiInventors: Kozo Ide, Mitsujiro Sawamura, Mengesha Mamo Wogari, Jun Oyama