Patents by Inventor Buyun Liu

Buyun Liu 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).

  • Patent number: 6759780
    Abstract: A brushless electric motor is disclosed. In an exemplary embodiment of the invention, the motor includes a permanent magnet rotor having a plurality of magnetic poles thereupon and a stator. The stator further includes a plurality of stacked laminations defining a plurality of slots therein, and a plurality of fractional-pitch phase windings disposed within the plurality of slots. The motor has a non-integer slots-per-pole ratio, and a magnitude of 5th and 7th harmonic components of a fundamental frequency component of the motor are less than 0.3% and 0.1% of a magnitude of the fundamental frequency component, respectively.
    Type: Grant
    Filed: May 8, 2001
    Date of Patent: July 6, 2004
    Assignee: Delphi Technologies, Inc.
    Inventors: Buyun Liu, Tomy Sebastian, Sunil Keshava Murthy
  • Patent number: 6713921
    Abstract: A permanent magnet structure for use in brushless motors is disclosed. In an exemplary embodiment of the invention, the magnet structure includes a parallelogram shaped body. The body has an outer surface and an inner surface, with the outer surface and the inner surface being arcuate in shape.
    Type: Grant
    Filed: May 8, 2001
    Date of Patent: March 30, 2004
    Assignee: Delphi Technologies, Inc.
    Inventors: Tomy Sebastian, Sunil Keshava Murthy, Buyun Liu, Mark F. Fleer
  • Publication number: 20020167241
    Abstract: A permanent magnet structure for use in brushless motors is disclosed. In an exemplary embodiment of the invention, the magnet structure includes a parallelogram shaped body. The body has an outer surface and an inner surface, with the outer surface and the inner surface being arcuate in shape.
    Type: Application
    Filed: May 8, 2001
    Publication date: November 14, 2002
    Inventors: Tomy Sebastian, Sunil Keshava Murthy, Buyun Liu, Mark F. Fleer
  • Publication number: 20020167242
    Abstract: A brushless electric motor is disclosed. In an exemplary embodiment of the invention, the motor includes a permanent magnet rotor having a plurality of magnetic poles thereupon and a stator. The stator further includes a plurality of stacked laminations defining a plurality of slots therein, and a plurality of fractional-pitch phase windings disposed within the plurality of slots. The motor has a non-integer slots-per-pole ratio, and a magnitude of 5th and 7th harmonic components of a fundamental frequency component of the motor are less than 0.3% and 0.1% of a magnitude of the fundamental frequency component, respectively.
    Type: Application
    Filed: May 8, 2001
    Publication date: November 14, 2002
    Inventors: Buyun Liu, Tomy Sebastian, Sunil Keshava Murthy
  • Patent number: 6437526
    Abstract: A system for reducing torque ripple in an electric motor, comprising an electric motor having a stator and a rotor, a first set of N Hall sensors, a second set of N Hall sensors, a controller, and wherein said N Hall sensors in each said set of Hall sensors is spaced 360/N electrical degrees apart and said first and second sets of Hall sensors are spaced T electrical degrees apart, and wherein said controller is adapted to provide increased current during an overlap period detected by said Hall sensors.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: August 20, 2002
    Assignee: Delphi Technologies, Inc.
    Inventors: Benoit Derouane, Sunil Keshava Murthy, Tomy Sebastian, Buyun Liu
  • Patent number: 6380658
    Abstract: A method for determining a dimension in a motor is described. By applying Fourier analysis, a sequence of terms is obtained. Since the fifth harmonic is the most undesirable term, the minimization of the fifth harmonic term will make resultant waveform closer to sine wave. Based upon the above, a determination of an angle &dgr; is described, wherein the fifth harmonic term of the sequence of terms is minimized. An electric motor having a rotor and a set of slot on said rotor surface having a set of magnets with a width &dgr; along the circumference of said rotor surface is described. The width &dgr; is determined by a method that includes applying Fourier analysis thereby a sequence of terms is obtained. Since the fifth harmonic is the most undesirable term, the minimization of the fifth harmonic term will make resultant waveform closer to sine wave. Based upon the above, a determination of an angle &dgr; is described, wherein the fifth harmonic term of the sequence of terms is minimized.
    Type: Grant
    Filed: July 14, 2000
    Date of Patent: April 30, 2002
    Assignee: Delphi Technologies Inc.
    Inventors: Tomy Sebastian, Sunil Keshava Murthy, Buyun Liu, Scott R Berggren