Patents by Inventor Subrata Saha

Subrata Saha 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: 20100140003
    Abstract: An electric motor control device includes an inverter that supplies an output of a primary-side DC power supply to an electric motor to control driving of the electric motor; a converter that includes a voltage increasing power supply device that increases a voltage of the primary-side DC power supply to supply the inverter with the increased voltage as a secondary voltage, and a regenerative power supply device that reversely supplies regenerative power from the inverter to the primary-side DC power supply; a secondary-side target voltage determination unit; a converter control unit; and an electric motor control unit.
    Type: Application
    Filed: October 31, 2008
    Publication date: June 10, 2010
    Applicant: AISIN AW CO., LTD.
    Inventors: Subrata Saha, Takashi Yoshida, Daisuke Ogino, Jin Izawa, Yoshinori Oono
  • Publication number: 20100026218
    Abstract: A rotating electrical machine control system includes a frequency converting portion that is interposed between a rotating electrical machine for driving a vehicle and a DC power source for supplying electric power to the rotating electrical machine, and that converts an output of the DC power source to an AC output at least during powering operation of the rotating electrical machine; a voltage converting portion that is interposed between the DC power source and the frequency converting portion, and that boosts the output of the DC power source based on a boost command value which is set according to a target torque and a rotational speed of the rotating electrical machine; and a control portion for controlling the frequency converting portion and the voltage converting portion.
    Type: Application
    Filed: July 1, 2009
    Publication date: February 4, 2010
    Applicant: AISIN AW CO., LTD.
    Inventors: Daisuke Ogino, Takashi Yoshida, Subrata Saha, Jin Izawa, Norio Tomiya
  • Publication number: 20100026217
    Abstract: A rotating electrical machine control system includes a frequency converting portion that is interposed between a rotating electrical machine for driving a vehicle and a DC power source for supplying electric power to the rotating electrical machine, and that converts an output of the DC power source to an AC output at least during a powering operation of the rotating electrical machine; a voltage converting portion that is interposed between the DC power source and the frequency converting portion, and that boosts the output of the DC power source based on a boost command value which is set according to a target torque and a rotational speed of the rotating electrical machine; and a control portion for controlling the frequency converting portion and the voltage converting portion.
    Type: Application
    Filed: July 1, 2009
    Publication date: February 4, 2010
    Applicant: AISIN AW CO., LTD.
    Inventors: Takashi Yoshida, Subrata Saha, Daisuke Ogino, Jin Izawa, Yoshinori Ono
  • Publication number: 20100026222
    Abstract: A dynamo-electric machine control system including a dynamo-electric machine and an inverter that is interposed between a battery and the dynamo-electric machine and that controls a current flowing through the dynamo-electric machine, wherein a rotation speed and an output torque of the dynamo-electric machine are controlled by the inverter, the dynamo-electric machine control system includes a battery power deriving unit that derives a battery power to be supplied from the battery when the dynamo-electric machine is operated at the rotation speed and the output torque; a limit power determining unit that variably determines a limit power, which is a maximum allowable value of the battery power, in accordance with a battery voltage; and a torque limiting unit that limits the torque of the dynamo-electric machine such that the battery power derived by the battery power deriving unit does not exceed the limit power.
    Type: Application
    Filed: July 1, 2009
    Publication date: February 4, 2010
    Applicant: AISIN AW CO., LTD.
    Inventors: Takashi Yoshida, Subrata Saha, Daisuke Ogino, Jin Izawa, Kazuo Aoki
  • Publication number: 20090243523
    Abstract: A control system includes an electric rotating machine; a driving circuit that is connected to a DC power supply, the driving circuit includes a frequency conversion unit configured such that, when the electric rotating machine is to be driven in a power running mode, the frequency conversion unit converts an output of the DC power supply into AC electric power, and when the electric rotating machine is to be driven in a regenerative operation mode, the frequency conversion unit converts an output of the electric rotating machine into DC electric power; and a control unit that controls the driving circuit, wherein the control unit judges whether a connection between the DC power supply and the driving circuit is being maintained, and is configured such that, when the connection is not being maintained, regenerative electric power generated by the electric rotating machine is reduced by controlling the driving circuit.
    Type: Application
    Filed: March 6, 2009
    Publication date: October 1, 2009
    Applicant: AISIN AW CO., LTD.
    Inventors: Kazuhiro Tanaka, Daisuke Ogino, Subrata Saha, Jin Izawa
  • Publication number: 20090115362
    Abstract: An electric motor control device includes a direct current power source; an inverter interposed between an electric motor and the direct current power source, the inverter device controlling an exchange of electric power therebetween; an inverter control unit that generates PWM pulses having a duty ratio corresponding to voltage command signals and sends the PWM pulses to the inverter in order to switch the inverter; a frequency changing unit that changes a carrier frequency of the PWM pulses generated by the inverter control unit in a manner corresponding to a frequency control signal; and a motor control unit.
    Type: Application
    Filed: October 31, 2008
    Publication date: May 7, 2009
    Applicant: AISIN AW CO., LTD.
    Inventors: Subrata Saha, Isao Fujiwara, Keisuke Nishimura, Kazuma Hasegawa, Yoshinori Oono, Seiichi Kinugasa
  • Publication number: 20080191648
    Abstract: In a closed loop control method of a linear vibration actuator which vibrates linearly and energized by a switching element driven in a PWM control method, a crest or peak point (Bc, Bp) of the back electromotive force occurring in the linear vibration actuator is detected (S14). The detected crest or peak point (Bc, Bp) is compared with a reference value (Bcr, Bpr) (S15), and adjusting the PWM duty (?) applied to the switching element and controlling the operating frequency of the linear vibration actuator to resonant frequency (S16 to S19), thereby keeping the crest or peak point (Bc, Bp) of the back electromotive force always constant.
    Type: Application
    Filed: February 27, 2003
    Publication date: August 14, 2008
    Inventors: Yoshiteru Ito, Subrata Saha, Taro Kishibe, Shinichiro Kawano, Koji Kameda, Kazushige Narazaki, Yasufumi Ikkai, Noriyoshi Nishiyama
  • Patent number: 7271556
    Abstract: A discrete rotor position estimation method for a synchronized reluctance motor is provided. A d.c.-link voltage Vdc and a phase current Iph are sensed. A flux-linkage ?ph of an active phase is calculated from the sensed d.c.-link voltage Vdc and the sensed phase current Iph. The calculated flux-linkage ?ph is compared with a reference flux-linkage ?r. The reference flux-linkage ?r corresponds to a reference angle ?r which lies between angles corresponding to aligned rotor position and non-aligned rotor position in the synchronized reluctance motor. An estimated rotor position ?cal is obtained only once when the calculated flux-linkage ?ph is greater than the reference flux-linkage ?r.
    Type: Grant
    Filed: November 28, 2002
    Date of Patent: September 18, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Taro Kishibe, Subrata Saha, Hiroshi Murakami, Kazushige Narazaki
  • Publication number: 20070023971
    Abstract: A method for sintering ceramic materials using a microwave hybrid heating system includes the steps of providing a ceramic member to be sintered, providing a microwave furnace, providing a thermal containment box comprising a material that is virtually transparent to microwave energy, providing at least one susceptor comprising a material that directly couples to microwave energy at room temperature substantially immediately within the thermal containment box, positioning the ceramic member within the thermal containment chamber proximate the susceptor, and irradiating the thermal containment box with microwave energy. The susceptor couples to the microwave energy and generates heat within the thermal containment box and the temperature of the ceramic member increases to the microwave coupling-trigger temperature, at which time the ceramic member couples directly to the microwave energy and is directly sintered by the microwave energy in cooperation with radiant energy from the one susceptor.
    Type: Application
    Filed: September 1, 2004
    Publication date: February 1, 2007
    Inventors: Subrata Saha, Ram Mohan V.C., Gary Delregno
  • Publication number: 20060125427
    Abstract: A discrete rotor position estimation method for a synchronized reluctance motor is provided. A d.c.-link voltage Vdc and a phase current Iph are sensed. A flux-linkage ?ph of an active phase is calculated from the sensed d.c.-link voltage Vdc and the sensed phase current Iph. The calculated flux-linkage ?ph is compared with a reference flux-linkage ?r. The reference flux-linkage ?r corresponds to a reference angle ?r which lies between angles corresponding to aligned rotor position and non-aligned rotor position in the synchronized reluctance motor. An estimated rotor position ?cal is obtained only once when the calculated flux-linkage ?ph is greater than the reference flux-linkage ?r.
    Type: Application
    Filed: November 28, 2002
    Publication date: June 15, 2006
    Inventors: Taro Kishibe, Subrata Saha, Hiroshi Murakami, Kazushige Narazaki
  • Patent number: 6879129
    Abstract: In a brushless motor control method and a brushless motor controller in accordance with the present invention, a rotor rotation position detection means detects the time of the intersection of a detected induced voltage and an induced voltage reference value. In addition, a motor speed calculation means calculates the rotation speed of a brushless motor on the basis of the interval of the intersection times detected by the rotor rotation position detection means. Furthermore, a speed control means outputs a duty factor index on the basis of the deviation between the command speed and the rotation speed of the brushless motor. Still further, a switching signal generation means outputs switching signals to groups of switching devices on the basis of the rotation speed and the duty factor index at the time of the intersection.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: April 12, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Toru Tazawa, Kazushige Narazaki, Tomokuni Iijima, Hideo Matsushiro, Subrata Saha
  • Publication number: 20020140395
    Abstract: In a brushless motor control method and a brushless motor controller in accordance with the present invention, a rotor rotation position detection means detects the time of the intersection of a detected induced voltage and an induced voltage reference value. In addition, a motor speed calculation means calculates the rotation speed of a brushless motor on the basis of the interval of the intersection times detected by the rotor rotation position detection means. Furthermore, a speed control means outputs a duty factor index on the basis of the deviation between the command speed and the rotation speed of the brushless motor. Still further, a switching signal generation means outputs switching signals to groups of switching devices on the basis of the rotation speed and the duty factor index at the time of the intersection.
    Type: Application
    Filed: March 28, 2002
    Publication date: October 3, 2002
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Toru Tazawa, Kazushige Narazaki, Tomokuni Iijima, Hideo Matsushiro, Subrata Saha
  • Patent number: 4235243
    Abstract: Method and apparatus for facilitating the non-invasive study of a piezoelectric member, the method including the steps of generating a stress wave in the member at one point and sensing the magnetic field generated in the member at a second point distal to the first point. The apparatus includes an ultrasonic driver for generating the stress wave in the member, and a magnetic field sensor for sensing the generated magnetic field.
    Type: Grant
    Filed: October 23, 1978
    Date of Patent: November 25, 1980
    Inventor: Subrata Saha