Patents by Inventor Silva Hiti

Silva Hiti 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: 20090033251
    Abstract: Systems and apparatus are provided for an inverter system for use in a vehicle. The inverter system comprises a six-phase motor having a first set of three-phase windings and a second set of three-phase windings and a three-phase motor having a third set of three-phase windings, wherein the third set of three-phase windings is coupled to the first set of three-phase windings and the second set of three-phase windings. The system further comprises a first energy source coupled to a first inverter adapted to drive the six-phase motor and the three-phase motor, wherein the first set of three-phase windings is coupled to the first inverter, and a second energy source coupled to a second inverter adapted to drive the six-phase motor and the three-phase motor, wherein the second set of three-phase windings is coupled to the second inverter. A controller is coupled to the first inverter and the second inverter.
    Type: Application
    Filed: May 1, 2008
    Publication date: February 5, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Milun Perisic, Silva Hiti, Gregory S. Smith, James M. Nagashima, George John, Sibaprasad Chakrabarti, Brian A. Welchko
  • Publication number: 20090026895
    Abstract: Electric motor systems are provided for use in vehicles. In an embodiment, by way of example only, the system includes a first inverter, a second inverter, and a motor electrically coupled to the first and the second inverters. The motor includes a stator including a plurality of slots formed therein and a plurality of windings. The plurality of windings is disposed at least partially in the slots, and each winding includes a first coil and a second coil. The first coil has a first number of turns, and the second coil has a second number of turns that is unequal to the first number of turns. The first coil of each winding is electrically coupled to the first inverter, and the second coil of each winding is electrically coupled to the second inverter.
    Type: Application
    Filed: July 27, 2007
    Publication date: January 29, 2009
    Inventors: Sibaprasad Chakrabarti, Silva Hiti
  • Publication number: 20090027000
    Abstract: Systems and methods are disclosed to provide torque linearity in the field-weakening region for an IPM machine. The systems and methods adjust the q-axis and the d-axis components of the stator current commands of the IPM machine using a flux weakening and a torque linearity control loop respectively. Thereby, torque linearity is maintained during the field weakening region of operation of the IPM machine.
    Type: Application
    Filed: July 27, 2007
    Publication date: January 29, 2009
    Inventors: Gabriel Gallegos-Lopez, Yo Chan Son, Milun Perisic, Silva Hiti
  • Patent number: 7483282
    Abstract: A method of using a cycloconverter switches a first switch of the first topology type to an on state after a magnitude of a current through an output inductor becomes less than a predetermined current threshold, and switches a second switch of the first topology type to an off state a first time after switching the first switch to the on state. The cycloconverter includes nodes on a first port, nodes on a second port, a switch pair coupled between a first node of the first port and a first node of the second port, a switch pair coupled between a second node of the first port and a first node of the second port, a switch pair coupled between a first node of the first port and a second node of the second port, and a switch pair coupled between a second node of the first port and a second node of the second port. Each switch pair includes a switch of each topology type.
    Type: Grant
    Filed: August 29, 2006
    Date of Patent: January 27, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Lateef A. Kajouke, Silva Hiti
  • Patent number: 7471526
    Abstract: Methods and apparatus are provided for reducing voltage distortion effects at low speed operation in electric drives. The method comprises receiving a first signal having a duty cycle with a range between minimum and maximum achievable duty cycles, producing a second duty cycle based on the minimum achievable duty cycle if the duty cycle is within a distortion range and less than a first clipping value, producing a second duty cycle based on the closer of minimum and maximum pulse widths if the duty cycle is within the distortion range and between the first and a second clipping value, producing a second duty cycle based on the maximum achievable duty cycle if the duty cycle is within the distortion range and greater than the second clipping value, and transmitting a second signal to the voltage source inverter having the second duty cycle.
    Type: Grant
    Filed: February 20, 2007
    Date of Patent: December 30, 2008
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Brian A Welchko, Bonho Bae, Steven E. Schulz, Silva Hiti
  • Publication number: 20080304189
    Abstract: Methods and apparatus are provided for protecting a motor control circuit in a permanent magnet electric motor system. The permanent magnet electric motor system includes a permanent magnet electric motor having a predetermined number of windings corresponding to the phases of the permanent magnet electric motor and a direct current (DC) bus coupled to a power source for providing operational power for the electric motor system. A motor control circuit is connected to the DC bus for receiving the operational power therefrom and is connected to the windings of the permanent magnet electric motor for controlling the permanent magnet electric motor. A protection circuit is connected to the DC bus for receiving the voltage therefrom for operation of the protection circuit and for detecting predetermined motor control circuit fault conditions from voltage sensed on the DC bus and in response thereto providing protection for the motor control circuit.
    Type: Application
    Filed: June 6, 2007
    Publication date: December 11, 2008
    Inventors: David Tang, Brian A. Welchko, Silva Hiti, Mark L. Selogie
  • Publication number: 20080303349
    Abstract: Systems and methods are disclosed for a two-source inverter. The systems and methods combines operation of a first voltage source powering a conventional single source inverter with second voltage source powering a novel switch configuration to power a load. The switch configuration is controlled by a plurality of control signals generated by controller based on a variety of control modes, and feedback signals.
    Type: Application
    Filed: June 8, 2007
    Publication date: December 11, 2008
    Inventors: Gabriel Gallegos-Lopez, James M. Nagashima, Silva Hiti
  • Publication number: 20080297100
    Abstract: Apparatus, systems, and methods are provided for reducing voltage source inverter losses. One apparatus includes a sensor couplable to the motor and configured to sense an operating frequency of the motor and an amount of torque produced by the motor. The apparatus also includes a controller coupled to the sensor, the controller configured to determine a zero vector modulation (ZVM) based on the sensed frequency and torque. A system includes means for sensing a threshold output frequency of the motor and means for sensing a threshold torque of the motor. The system also includes means for determining a ZVM for the inverter based on the sensed threshold frequency and threshold torque. One method includes sensing that a motor is operating below a threshold frequency and is producing torque above a threshold torque amount. The method also includes determining a ZVM for the inverter based on the sensed frequency and torque.
    Type: Application
    Filed: May 31, 2007
    Publication date: December 4, 2008
    Inventors: Silva Hiti, Steven E. Schulz, Brian A. Welchko
  • Publication number: 20080298785
    Abstract: Methods and systems for operating a motor coupled to an electrical bus in a vehicle are provided. Selected resonant frequencies of the electrical bus are determined. The selected resonant frequencies include a low resonant frequency and a high resonant frequency. Power is provided to the motor through at least one switch operating at a switching frequency. The switching frequency is controlled as a function of a rate of operation of the motor. The function is characterized by one of a first substantially linear portion having a first slope when the switching frequency is less than or equal to a selected switching frequency and a second substantially linear portion having a second slope if the switching frequency is greater than the selected frequency, the selected switching frequency being greater than the low resonant frequency and a substantially linear portion having a y-intercept being greater than the low resonant frequency.
    Type: Application
    Filed: May 31, 2007
    Publication date: December 4, 2008
    Inventors: Nitinkumar R. Patel, Mohammad N. Anwar, Silva Hiti, Brian A. Welchko, Steven E. Schulz, Lisa M. Talarico
  • Patent number: 7449859
    Abstract: A control architecture for an electrical inverter includes a synchronous frame current regulator and a stationary frame current regulator. The stationary frame current regulator receives input currents that represent filtered versions of stationary frame currents that correspond to the inverter output currents. The control architecture employs an adaptive filter module that filters the stationary frame currents to remove the fundamental motor frequency component (and its related harmonics), thus extracting any low frequency harmonic components. The stationary frame current regulator processes the low frequency components, while the synchronous frame current regulator processes the fundamental frequency component, resulting in suppression of low frequency oscillations in the inverter output.
    Type: Grant
    Filed: February 20, 2007
    Date of Patent: November 11, 2008
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Bonho Bae, Nitinkumar R. Patel, Steven E. Schulz, Silva Hiti
  • Publication number: 20080258673
    Abstract: Method and system are provided for controlling an alternating current (AC) motor via an inverter. The method includes selecting a pulse sequencing method based on a modulation index of the inverter, and providing a voltage to the AC motor based on the pulse sequencing method. The system includes an inverter having a modulation index (Mi) and a controller coupled to the inverter. The controller selects a pulse sequencing method based on Mi and produces a signal based on the pulse sequencing method. The inverter includes a switch network producing a voltage in response to the signal, and the voltage drives the AC motor.
    Type: Application
    Filed: April 18, 2007
    Publication date: October 23, 2008
    Inventors: Brian A. Welchko, Steven E. Schulz, Silva Hiti
  • Patent number: 7432683
    Abstract: A method for controlling an inverter uses sequences of predetermined states where each state uniquely corresponding to a set of control signals provided to the inverter that is coupled to a motor. The method includes repeatedly applying a first center null timing sequence of the states while monitoring a zero crossing condition and then changing the repeated application of the first center null timing sequence of the states into a repeated application of a second center null timing sequence of states when the monitoring detects a zero crossing condition. The repeated application of the first center null timing sequence sequentially provides the inverter with a first predetermined sequence of sets of control signals. The monitoring of a zero crossing condition monitors for a zero crossing condition in an electrical current flowing between the inverter and a terminal of the motor. The second center null timing sequence defines a second predetermined sequence of sets of control signals.
    Type: Grant
    Filed: November 20, 2006
    Date of Patent: October 7, 2008
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Brian Welchko, Steven E. Schulz, Silva Hiti, Stephen T. West
  • Publication number: 20080224651
    Abstract: Methods and systems are provided for controlling permanent magnet machines under varying loads. The method comprises generating a d-axis voltage command and a q-axis voltage command, producing a modified d-axis current command based on the q-axis voltage command and a d-axis current command, converting the modified d-axis current command to a modified d-axis voltage command, and transmitting the modified d-axis voltage command and the q-axis voltage command to the PM machine. The d-axis voltage command is based on a d-axis current command.
    Type: Application
    Filed: March 13, 2007
    Publication date: September 18, 2008
    Inventors: Steven E. Schulz, Silva Hiti, Khwaja M. Rahman
  • Publication number: 20080224649
    Abstract: A control architecture for an electrical inverter includes a command limiter that is realized as a circular voltage limiter. The command limiter includes a Cartesian-to-polar converter coupled to a command source such as a synchronous frame current regulator. The Cartesian-to-polar converter provides magnitude and phase components for d-q command voltages. The command limiter further includes a magnitude limiter that limits the magnitude component to the maximum fundamental voltage component of the inverter, and a polar-to-Cartesian converter that converts the limited magnitude component and the phase component into modified d-q command voltages.
    Type: Application
    Filed: March 13, 2007
    Publication date: September 18, 2008
    Inventors: Bonho Bae, Steven E. Schulz, Silva Hiti, Nitinkumar R. Patel
  • Publication number: 20080197800
    Abstract: A control architecture for an electrical inverter includes a synchronous frame current regulator and a stationary frame current regulator. The stationary frame current regulator receives input currents that represent filtered versions of stationary frame currents that correspond to the inverter output currents. The control architecture employs an adaptive filter module that filters the stationary frame currents to remove the fundamental motor frequency component (and its related harmonics), thus extracting any low frequency harmonic components. The stationary frame current regulator processes the low frequency components, while the synchronous frame current regulator processes the fundamental frequency component, resulting in suppression of low frequency oscillations in the inverter output.
    Type: Application
    Filed: February 20, 2007
    Publication date: August 21, 2008
    Inventors: Bonho Bae, Nitinkumar R. Patel, Steven E. Schulz, Silva Hiti
  • Publication number: 20080197902
    Abstract: Methods and apparatus are provided for reducing voltage distortion effects at low speed operation in electric drives. The method comprises receiving a first signal having a duty cycle with a range between minimum and maximum achievable duty cycles, producing a second duty cycle based on the minimum achievable duty cycle if the duty cycle is within a distortion range and less than a first clipping value, producing a second duty cycle based on the closer of minimum and maximum pulse widths if the duty cycle is within the distortion range and between the first and a second clipping value, producing a second duty cycle based on the maximum achievable duty cycle if the duty cycle is within the distortion range and greater than the second clipping value, and transmitting a second signal to the voltage source inverter having the second duty cycle.
    Type: Application
    Filed: February 20, 2007
    Publication date: August 21, 2008
    Inventors: Brian A. Welchko, Bonho Bae, Steven E. Schulz, Silva Hiti
  • Patent number: 7411801
    Abstract: Methods and apparatus are provided for modifying a pulse width modulation signal controlling a voltage source inverter. The method comprises the steps of determining a duty cycle of the signal, clipping the duty cycle when a modulation index is greater than a minimum modulation index and less than a maximum modulation index, clipping the duty cycle when the modulation index is greater than or equal to the maximum modulation index, and transmitting the duty cycle to the voltage source inverter. The minimum modulation index indicates a distortion range.
    Type: Grant
    Filed: December 14, 2005
    Date of Patent: August 12, 2008
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Brian Welchko, Steven E. Schulz, Silva Hiti
  • Publication number: 20080183405
    Abstract: In an embodiment of a method, the method includes measuring currents and voltages that are coupled to a motor that includes an internal permanent magnet and determining a reactive power in response to the measured currents and voltages. The method further includes estimating a first flux orthogonal to an axis of the internal permanent motor and estimating a second flux aligned with the axis of the internal permanent motor. Additionally, the method includes estimating a torque in response to the measured currents and the first and second fluxes.
    Type: Application
    Filed: January 30, 2007
    Publication date: July 31, 2008
    Inventors: Brian A. Welchko, Silva Hiti, Steven E. Schulz
  • Patent number: 7391181
    Abstract: A dynamic pulse width modulation (PWM) selection device automatically switches between discontinuous PWM (DPWM) control methods. The PWM selection device comprises a PWM control module. The PWM control module determines a desired pulse width of a switching control signal according to a desired output signal. The PWM control module controls an actual pulse width of the switching control signal according to the desired pulse width and a first PWM control method. A selection module determines whether the desired pulse width exceeds a pulse width threshold. The selection module selects a second PWM control method when the desired pulse width exceeds the pulse width threshold.
    Type: Grant
    Filed: March 16, 2006
    Date of Patent: June 24, 2008
    Assignee: General Motors Corporation
    Inventors: Brian Welchko, Steven E. Schulz, Silva Hiti
  • Publication number: 20080116840
    Abstract: A method for controlling an inverter uses sequences of predetermined states where each state uniquely corresponding to a set of control signals provided to the inverter that is coupled to a motor. The method includes repeatedly applying a first center null timing sequence of the states while monitoring a zero crossing condition and then changing the repeated application of the first center null timing sequence of the states into a repeated application of a second center null timing sequence of states when the monitoring detects a zero crossing condition. The repeated application of the first center null timing sequence sequentially provides the inverter with a first predetermined sequence of sets of control signals. The monitoring of a zero crossing condition monitors for a zero crossing condition in an electrical current flowing between the inverter and a terminal of the motor. The second center null timing sequence defines a second predetermined sequence of sets of control signals.
    Type: Application
    Filed: November 20, 2006
    Publication date: May 22, 2008
    Inventors: Brian Welchko, Steven E. Schulz, Silva Hiti, Stephen T. West