Patents by Inventor Doug Deng

Doug Deng 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: 6583996
    Abstract: A method and system for detecting the negative sequence of three phase grid-connected inverter systems utilizes, for example, computer hardware and/or computer software to remove a direct current component from a direct-axis current feedback for a three phase current of the inverter system to yield a pure alternating current waveform signal. A first low pass filter eliminates high frequency noise from the alternating current waveform signal while passing a negative sequence signal. The filtered signal is rectified to an absolute value, and a second low pass filter flattens the rectified signal to an output signal that is indicative of the magnitude of the negative sequence current.
    Type: Grant
    Filed: November 14, 2001
    Date of Patent: June 24, 2003
    Assignee: Ballard Power Systems Corporation
    Inventors: Doug Deng, Kon-King Mike Wang
  • Patent number: 5739664
    Abstract: An induction motor control system for electric vehicles having a DC power supply, an inverter, and an induction motor, includes a current control mechanism having a flux controller. The flux controller reduces the stator flux to improve the torque output of a motor at the limit of the voltage supply from the inverter. The reduction in flux is adjustable as the actual limit of voltage available to power the motor varies. A flux reference .lambda..sub.so generated according to efficiency control requirements can be adjusted by a flux weakening quantity generated by the controller in the constant power range of operation. The DC bus voltage, the rotor speed and stator flux reference values are input to the flux controller so that the motor can be operated to achieve improved torque output approaching the theoretical maximum torque output or to maximize efficiency as needed.
    Type: Grant
    Filed: February 5, 1996
    Date of Patent: April 14, 1998
    Assignee: Ford Global Technologies, Inc.
    Inventors: Doug Deng, Xingyi Xu
  • Patent number: 5627446
    Abstract: In one embodiment of the present invention, a control method for an induction motor includes calculating a desired quadrature-axis voltage and a desired direct-axis voltage according to both current control and voltage control. Below a predetermined motor speed, the motor is controlled in accordance with current control only. Above that predetermined speed, the two desired quadrature-axis voltages are combined in relative proportions, with the influence of voltage control being greater with higher motor speed. The two desired direct-axis voltages are likewise combined. The influence of voltage control thus increases with increasing motor speed. Above a second motor speed threshold, the motor is controlled in accordance with voltage control only.
    Type: Grant
    Filed: July 5, 1995
    Date of Patent: May 6, 1997
    Assignee: Ford Motor Company
    Inventors: Doug Deng, Xingyi Xu
  • Patent number: 5552977
    Abstract: When negative times are calculated for zero space vectors of a SVPWM controlled three phase inverter circuit, the zero vector times are set to zero, the non-zero space vector closer to a commanded space vector is preserved, and the non-zero space vector farther from the commanded space vector is truncated. Thus, control of the inverter circuit seamlessly transits from SVPWM to full six step operation. In one arrangement, for each negative calculated zero space vector time, the larger of the non-zero space vector times is set to the minimum of its calculated time and the pulse width modulation control period (TPWM), and the smaller of the calculated non-zero space vector times is set equal to TPWM less the set value of the larger of the non-zero space vector times. In another arrangement, each negative calculated zero space vector time is algebraically combined with the smaller of the non-zero space vector times.
    Type: Grant
    Filed: June 20, 1995
    Date of Patent: September 3, 1996
    Assignee: Ford Motor Company
    Inventors: Xingyi Xu, Doug Deng