Patents by Inventor Dal Ho Cheong

Dal Ho Cheong 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: 6735284
    Abstract: The present invention relates to a system and a method for controlling a motor. A rotation/fixed coordinates converter converts a reference magnetic flux voltage and a reference torque voltage of a rotation coordinates system into data of a fixed coordinates system, and outputs the data to the three-phase voltage generator. A fixed/rotation coordinates converter converts a three-phase current applied from the inverter to the motor into a two-phase current. An estimation unit estimates a rotation angle and rotor speed of the motor upon receiving currents applied to the fixed/rotation coordinates converter. A control block receives the estimated rotation angle and the estimated speed from the estimation unit, and outputs the reference magnetic flux voltage and the reference torque voltage of the motor to the rotation/fixed coordinates converter to compensate an error caused by loads generated when driving the motor.
    Type: Grant
    Filed: April 14, 2003
    Date of Patent: May 11, 2004
    Assignee: LG Electronics Inc.
    Inventors: Dal Ho Cheong, June Hee Won, Jae Yoon Oh, Kyung Hoon Lee
  • Patent number: 6724168
    Abstract: An apparatus is provided for controlling rotation speed of a synchronous reluctance motor, including a position estimation unit for controlling rotation speed of the synchronous reluctance motor by estimating the position angle of the rotor and rotation speed of the rotor according to the low speed or high speed region. The apparatus can control the motor in the high speed area or low speed area, stabilize the transient state generated in the process that the motor is converted from the low speed area to the high speed area and show stable speed control performance, thus performing more precise speed control.
    Type: Grant
    Filed: June 14, 2002
    Date of Patent: April 20, 2004
    Assignee: LG Electronics, Inc.
    Inventors: Dal-Ho Cheong, Jae-Yoon Oh, Kyung-Hoon Lee
  • Publication number: 20040070364
    Abstract: The present invention relates to a system and a method for controlling a motor. A rotation/fixed coordinates converter converts a reference magnetic flux voltage and a reference torque voltage of a rotation coordinates system into data of a fixed coordinates system, and outputs the data to the three-phase voltage generator. A fixed/rotation coordinates converter converts a three-phase current applied from the inverter to the motor into a two-phase current. An estimation unit estimates a rotation angle and rotor speed of the motor upon receiving currents applied to the fixed/rotation coordinates converter. A control block receives the estimated rotation angle and the estimated speed from the estimation unit, and outputs the reference magnetic flux voltage and the reference torque voltage of the motor to the rotation/fixed coordinates converter to compensate an error caused by loads generated when driving the motor.
    Type: Application
    Filed: April 14, 2003
    Publication date: April 15, 2004
    Applicant: LG Electronics Inc.
    Inventors: Dal Ho Cheong, June Hee Won, Jae Yoon Oh, Kyung Hoon Lee
  • Publication number: 20040061472
    Abstract: Disclosed are a flux observer and a sensorless control system of a synchronous reluctance motor. The flux observer includes an estimated flux output unit, a measured flux output unit, and a fixed/rotational coordinate converter. The flux observer estimates a flux of a synchronous reluctance motor by removing higher harmonic components of a current in a rotational coordinate system which flows into the motor. The measured flux output unit measures a flux in a fixed coordinate system by combining a voltage in the fixed coordinate system, which is applied to the motor, and a current in the fixed coordinate system, from which higher harmonic components are removed, with the estimated flux outputted from the estimated flux output unit. The fixed/rotational coordinate converter converts the measured flux outputted from the measured flux output unit to a measured flux in the rotational coordinate system.
    Type: Application
    Filed: July 9, 2003
    Publication date: April 1, 2004
    Applicant: LG Electronics Inc.
    Inventors: June Hee Won, Jae Yoon Oh, Kyung Hoon Lee, Dal Ho Cheong
  • Patent number: 6646409
    Abstract: An apparatus for controlling the rotation speed of a motor, which is capable of controlling the rotation speed and the torque of the motor by detecting the input voltage and the input current of the motor without using a sensor for detecting the position of the rotor of the motor, is provided.
    Type: Grant
    Filed: January 8, 2002
    Date of Patent: November 11, 2003
    Assignee: LG Electronics Inc.
    Inventors: June Hee Won, Dal Ho Cheong, Jae Yoon Oh, Kyung Hoon Lee
  • Patent number: 6525497
    Abstract: Disclosed are a phase distortion compensating apparatus and method for reducing a torque ripple in a 3-phase motor using four switching elements, which are capable of adjusting respective switching times of phase voltages, to be supplied to the 3-phase motor by an inverter including the switching elements, based on a voltage difference between upper and lower DC link capacitors respectively adapted to supply voltages to the inverter, thereby reducing a torque ripple generated in the motor.
    Type: Grant
    Filed: March 21, 2001
    Date of Patent: February 25, 2003
    Assignee: LG Electronics Inc.
    Inventors: Dong Myung Lee, Jae Yoon Oh, Dal Ho Cheong
  • Publication number: 20030025475
    Abstract: An apparatus for controlling the rotation speed of a motor, which is capable of controlling the rotation speed and the torque of the motor by detecting the input voltage and the input current of the motor without using a sensor for detecting the position of the rotor of the motor, is provided.
    Type: Application
    Filed: January 8, 2002
    Publication date: February 6, 2003
    Applicant: LG Electronics Inc.
    Inventors: June Hee Won, Dal Ho Cheong, Jae Yoon Oh, Kyung Hoon Lee
  • Publication number: 20030020351
    Abstract: A rotor for a synchronous reluctance motor of flux barrier type and manufacturing method thereof constructs a rotor for a synchronous reluctance motor by forming a magnetic core steel plate of disc shape on which a shaft hole is formed at center part, and a plurality of flux barrier groups are formed centering around the shaft hole and automatic stacking points are formed; manufacturing a plate stacked body by stacking the core steel plates continuously using the automatic stacking points; disposing end plates on both sides of the plate stacked body; and coupling the end plates and the plate stacked body integrally with each other as inserting a coupling member into the flux barrier groups, whereby the manufacturing process can be made easy and automatic stacking of the core steel plates can be made regardless of the types such as a skew type or a non skew type, and therefore manufacturing cost is reduced and the rotor can be mass produced.
    Type: Application
    Filed: January 15, 2002
    Publication date: January 30, 2003
    Applicant: LG Electronics Inc.
    Inventors: Kyung Hun Lee, Jae Yoon Oh, Dal Ho Cheong
  • Publication number: 20030015987
    Abstract: A conventional apparatus with the above operation, includes a torque ripple due to harmonic wave components included in the detected fundamental wave of current frequency of the detected apparatus for controlling rotation speed, switching dead time and the like and accordingly, harmonic wave components are included in the induced voltage. Therefore, a ripple is generated in an estimated-calculated rotation speed and accordingly, precise speed control was not possible. Also, it was difficult to handle the apparatus by using an encoder and hole-sensor of the rotor position detection unit.
    Type: Application
    Filed: June 14, 2002
    Publication date: January 23, 2003
    Inventors: Dal-Ho Cheong, Jae-Yoon Oh, Kyung-Hoon Lee
  • Patent number: 6388903
    Abstract: Disclosed are a voltage compensating apparatus and method for a 3-phase inverter using four switches, to compensate for a severe distortion of a 3-phase application voltage due to a voltage ripple.
    Type: Grant
    Filed: May 10, 2001
    Date of Patent: May 14, 2002
    Assignee: LG Electronics Inc.
    Inventors: Dong Myung Lee, Jae Yoon Oh, Dal Ho Cheong, Soon Bae Yang
  • Publication number: 20020053891
    Abstract: Disclosed are a phase distortion compensating apparatus and method for reducing a torque ripple in a 3-phase motor using four switching elements, which are capable of adjusting respective switching times of phase voltages, to be supplied to the 3-phase motor by an inverter including the switching elements, based on a voltage difference between upper and lower DC link capacitors respectively adapted to supply voltages to the inverter, thereby reducing a torque ripple generated in the motor.
    Type: Application
    Filed: March 21, 2001
    Publication date: May 9, 2002
    Inventors: Dong Myung Lee, Jae Yoon Oh, Dal Ho Cheong
  • Publication number: 20020012255
    Abstract: Disclosed are a voltage compensating apparatus and method for a 3-phase inverter using four switches, to compensate for a severe distortion of a 3-phase application voltage due to a voltage ripple.
    Type: Application
    Filed: May 10, 2001
    Publication date: January 31, 2002
    Inventors: Dong Myung Lee, Jae Yoon Oh, Dal Ho Cheong, Soon Bae Yang
  • Publication number: 20010028236
    Abstract: A speed control apparatus for a synchronous reluctance motor is disclosed. The speed control apparatus includes a voltage detector for detecting a voltage applied to the motor, a first phase converter for receiving voltages in three phases from the voltage detector and converting the three-phase voltages into equivalent voltages in two phases, a current detector for detecting a current applied to the motor, a second phase converter for receiving currents in three phases from the current detector and converting the three-phase currents into equivalent currents in two phases, and a rotor speed operator for receiving the two-phase voltages thereby computing a speed of a rotor included in the motor. A speed controller for receiving a deviation between a speed command externally inputted and an output value from the rotor speed operator is provided for generating a torque-related current command.
    Type: Application
    Filed: March 23, 2001
    Publication date: October 11, 2001
    Inventor: Dal-Ho Cheong
  • Patent number: 5682634
    Abstract: This invention relates to a method and apparatus for controlling the speed of a washing machine motor by varying the number of revolutions and changing direction of rotation of the motor to control the water current of the washing machine. The invention detects the actual speed of the washing machine motor at every half cycle of ordinary use power frequency, determines speed error by comparing the detected actual speed with an ordered speed, determines a speed state from the speed error, calculates a proportional integration value according to the determined speed state, and scales the calculated proportional compensation value into an angular value. The washing machine's motor speed is controlled using the scaled angular value.
    Type: Grant
    Filed: November 16, 1994
    Date of Patent: November 4, 1997
    Assignee: Goldstar Co., Ltd.
    Inventors: Dal Ho Cheong, Doo Whan Sang