Patents by Inventor Amara Ashfaq

Amara Ashfaq 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: 20220231626
    Abstract: Power based self-sensing of a rotor position of an SR motor at mid to high speeds and low torque is achieved by an SR motor control system by comparing the motor power to an injection maximum power. A position current pulse is injected to a stator pole in response to the motor power being less than the injection maximum power. An actual stator current created by the position current pulse is compared to an estimated stator current, and a stored estimated rotor position in a memory is updated to a new estimated rotor position if the actual stator current is not equal to the estimated stator current.
    Type: Application
    Filed: January 21, 2021
    Publication date: July 21, 2022
    Applicant: Caterpillar Inc.
    Inventors: Jesse Ray Gerdes, James Michael Thorne, Ahmed Khalil, Jackson Wai, Sajan Abdul, Amara Ashfaq
  • Publication number: 20220200501
    Abstract: A work machine includes a frame, a traction system supporting the frame, a power source mounted on the frame, a switched reluctance motor, an inverter configured to control power to the motor from a power source, and a controller. The controller is configured to receive a signal indicating a desired torque and determine if the desired torque is between an upper threshold and a lower threshold. If the desired torque is between the upper threshold and the lower threshold, pulse width modulation is used to produce a PWM adjusted torque command, and the motor is commanded based on the PWM adjusted torque command. The PWM adjusted torque command is configured to cycle between the upper threshold and the lower threshold to produce the desired torque.
    Type: Application
    Filed: December 23, 2020
    Publication date: June 23, 2022
    Applicant: Caterpillar Inc.
    Inventors: Jesse R. Gerdes, Thomas M. Sopko, Carlos E. Nino Baron, Jackson Wai, Ahmed Khalil, Sajan Abdul, Amara Ashfaq, James Michael Thorne
  • Publication number: 20220200502
    Abstract: A system and method for torque compensation in a switched reluctance (SR) machine disposed on a machine is disclosed. The system may comprise a SR machine, an inverter and a controller. The controller is in operable communication with the inverter and is configured to determine a commanded main current associated with energization by a main current of a first portion of the plurality of windings for a controlling phase, and determine a commanded parasitic current associated with energization by a parasitic current of a second portion of the windings in a non-controlling phase. The controller is further configured to determine an offset current based on the commanded parasitic current, and determine a target current based on a first sum of the commanded main current and the offset current, and command the inverter to actuate the target current in the first portion of the windings during the controlling phase.
    Type: Application
    Filed: December 21, 2020
    Publication date: June 23, 2022
    Applicant: Caterpillar Inc.
    Inventors: Jesse R. Gerdes, Jackson Wai, Ahmed Khalil, James Michael Thorne, Sajan Abdul, Amara Ashfaq
  • Patent number: 10938332
    Abstract: A control system that includes a converter circuit and a control device is disclosed. The converter circuit may be configured to control a phase current of a switched reluctance machine. The control device may be configured to determine an estimated flux based on a bus voltage, a phase voltage, and a mutual voltage. The control device may be configured to determine a flux threshold based on the phase current, and determine a first limit and a second limit relative to the flux threshold. The first limit and the second limit may be scaled relative to the flux threshold based on one or more of the target speed, the load demand, or the bus voltage. The control device may be configured to compare the estimated flux with the first limit, and reset the estimated flux to the second limit based on determining that the estimated flux satisfies the first limit.
    Type: Grant
    Filed: October 7, 2019
    Date of Patent: March 2, 2021
    Assignee: Caterpillar Inc.
    Inventors: Ahmed Khalil, James Thorne, Jackson Wai, Amara Ashfaq, Jesse Gerdes