Patents by Inventor Steven E. Schulz

Steven E. Schulz 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: 20090230900
    Abstract: Methods and systems are provided for controlling an AC motor via an inverter. The method includes determining a delay-compensated offset based on a synchronous frame current, producing a current error based on a synchronous frame current and a commanded current, producing a voltage error based on an anti-windup offset and the current error, producing a commanded voltage based on the delay-compensated offset and the voltage error, and providing the inverter with the commanded voltage.
    Type: Application
    Filed: March 13, 2008
    Publication date: September 17, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: BONHO BAE, NITINKUMAR R. PATEL, STEVEN E. SCHULZ, JAMES M. NAGASHIMA, JUNG SIK YIM, SEUNG KI SUL
  • Patent number: 7576500
    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: Grant
    Filed: May 31, 2007
    Date of Patent: August 18, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Nitinkumar R. Patel, Mohammad N. Anwar, Silva Hiti, Brian A Welchko, Steven E. Schulz, Lisa M. Talarico
  • Publication number: 20090189561
    Abstract: A temperature estimation controller and methods are provided for controlling a torque command to prevent overheating of one or more of a plurality of phases of a permanent magnet motor. The temperature estimation controller includes a low speed temperature estimation module, a transition module and a temperature dependent torque command derater block. The low speed temperature estimation module determines a stator temperature of each of a plurality of phases of the permanent magnet motor in response to first thermal impedances measured for each of the plurality of phases with respect to a thermal neutral. The transition module is coupled to the low speed temperature estimation module and outputs the stator temperature of each of a plurality of phases of the permanent magnet motor as determined by the low speed temperature estimation module when a detected speed of the permanent magnet motor is less than a first predetermined speed.
    Type: Application
    Filed: January 24, 2008
    Publication date: July 30, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: NITINKUMAR R. PATEL, YO CHAN SON, SILVA HITI, STEVEN E. SCHULZ
  • Publication number: 20090179608
    Abstract: Methods and systems for controlling a power inverter in an electric drive system of an automobile are provided. A signal controlling the power inverter is modified utilizing a first voltage distortion compensation method if a modulation index of the signal is less than a first modulation index value. The signal is modified utilizing a second voltage distortion compensation method if the modulation index is at least equal to the first modulation index value.
    Type: Application
    Filed: January 11, 2008
    Publication date: July 16, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Brian A. WELCHKO, Steven E. SCHULZ, Silva HITI
  • Publication number: 20090140676
    Abstract: Methods and systems for controlling an electric motor are provided. A signal comprising at least first and second cycles is provided to the electric motor. A first flux value for the electric motor associated with the first cycle of the signal is calculated. A second flux value for the electric motor associated with the second cycle of the signal is calculated based on the first flux value.
    Type: Application
    Filed: November 29, 2007
    Publication date: June 4, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: YO CHAN SON, NITINKUMAR R. PATEL, STEVEN E. SCHULZ
  • Publication number: 20090134833
    Abstract: In various embodiments, a phase current sampling apparatus (300, 600, FIGS. 3, 6), an electric motor drive system (100, FIG. 1), and a motor vehicle (1200, FIG. 12) include switching circuitry adapted to receive first and second phase current waveforms. The switching circuitry provides the first phase current waveform during at least two offset sampling instants, and provides the second phase current waveform during a reference sampling instant. An analog-to-digital converter is adapted to sample the first phase current waveform at the offset sampling instants, and to sample the second phase current waveform at the reference sampling instant. An embodiment of a method for regulating phase current waveforms includes an analog-to-digital converter generating samples of a first phase current waveform at sampling instants that occur before and after a reference sampling instant, and generating a sample of a second phase current waveform at the reference sampling instant.
    Type: Application
    Filed: November 26, 2007
    Publication date: May 28, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: STEPHEN T. WEST, BRIAN A. WELCHKO, STEVEN E. SCHULZ, SILVA HITI
  • Publication number: 20090134835
    Abstract: In various embodiments, an electric motor drive system (400, FIG. 4) and a motor vehicle (1000, FIG. 10) include an inverter (404, FIG. 4) adapted to generate (604, FIG. 6), based on inverter control inputs, a number, N, of phase current waveforms (118, FIG. 1), and a phase current sampling apparatus (408, FIG. 4) having a same number, N, of current sensors (502, 503, 504, FIG. 5). Each of the current sensors is adapted to receive one of the phase current waveforms, and the current sensors are adapted simultaneously to sample the phase current waveforms and to generate digital values representing amplitudes of the phase current waveforms. The system and motor vehicle also include a controller (410, FIG. 4) adapted to receive the digital values, to perform an evaluation of the digital values, and to generate the inverter control inputs (462, FIG. 4) based on the evaluation.
    Type: Application
    Filed: November 26, 2007
    Publication date: May 28, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: BRIAN A. WELCHKO, STEVEN E. SCHULZ, SILVA HITI
  • Publication number: 20090108780
    Abstract: Methods and systems for controlling a power inverter in an electric drive system of an automobile are provided. The various embodiments control the power inverter by, responsive to a commanded torque of the electric motor being below a first torque level, controlling the power inverter to set a switching frequency of the power inverter at a first set frequency; and, responsive to the commanded torque of the electric motor being between the first torque level and a second torque level, controlling the power inverter to determine the switching frequency of the power inverter as a function of the commanded torque of the electric motor while maintaining the switching frequency above a dynamic frequency limit. The method reduces switching frequencies in the inverter at high commanded torques, while maintaining the switching frequencies above dynamic frequency limit that provides effective control over the motor.
    Type: Application
    Filed: October 24, 2007
    Publication date: April 30, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: STEVEN E. SCHULZ, STEPHEN T. WEST, BRIAN A. WELCHKO, SILVA HITI
  • Publication number: 20090107742
    Abstract: Methods and systems for controlling a power inverter in automobiles utilizing two-mode transmissions are provided. The various embodiments control the power inverter by, responsive to a commanded torque of the electric motor being below a first torque level, controlling the power inverter to set a switching frequency of the power inverter at a first set frequency; and, responsive to the commanded torque of the electric motor being between the first torque level and a second torque level, controlling the power inverter to determine the switching frequency of the power inverter as a function of the commanded torque of the electric motor while maintaining the switching frequency above a dynamic frequency limit. The method reduces switching frequencies in the inverter at high commanded torques, while maintaining the switching frequencies above dynamic frequency limit that provides effective control over the motor.
    Type: Application
    Filed: October 24, 2007
    Publication date: April 30, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: STEVEN E. SCHULZ, STEPHEN T. WEST, BRIAN A. WELCHKO, SILVA HITI
  • Publication number: 20090108798
    Abstract: Methods and systems for controlling a power inverter in an electric drive system of an automobile are provided. The various embodiments control the power inverter by, responsive to either a commanded torque of the electric motor being above a first torque level, or a commanded speed of the electric motor being above a first speed level, controlling the power inverter with a discontinuous pulse width modulated (DPWM) signal to generate a modulated voltage waveform for driving the electric motor. Additionally, the embodiments control the power inverter by, responsive to both a commanded torque of the electric motor being below the first torque level, and a commanded speed of the electric motor being below the first speed level, controlling the power inverter with a continuous pulse width modulated (CPWM) signal to generate the modulated voltage waveform for driving the electric motor.
    Type: Application
    Filed: October 24, 2007
    Publication date: April 30, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: STEVEN E. SCHULZ, BRIAN A. WELCHKO, SILVA HITI
  • Patent number: 7518335
    Abstract: A method for controlling an alternating current (AC) motor includes choosing a pulse sequence based on a ripple current in the AC motor at a sampling instant; and providing a voltage to the AC motor based on the pulse sequence.
    Type: Grant
    Filed: August 4, 2006
    Date of Patent: April 14, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Stephen T. West, Brian Welchko, Steven E. Schulz, Silva Hiti
  • Publication number: 20090088294
    Abstract: Temperature of an electric drive is regulated to prevent undesirable thermal effects. Temperature conditions of the electric drive system are monitored and torque of the electric drive system is limited based on the temperature conditions.
    Type: Application
    Filed: September 28, 2007
    Publication date: April 2, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Stephen T. West, Wei D. Wang, Brian A. Welchko, Steven E. Schulz, Peter E. Wu
  • Publication number: 20090072778
    Abstract: Methods and apparatus are provided for providing a torque boost in an electric motor system at low speeds. The electric motor system comprises an alternating current (AC) synchronous electric motor, an inverter and a controller. The inverter is coupled to the AC synchronous electric motor and provides electric control therefore. The controller is coupled to the inverter and provides operational control signals thereto for operation of the electric motor. The controller includes a torque command gain block which modifies a torque command to generate a boosted torque signal in response to a detected speed of the electric motor, the torque command modified to define the boosted torque signal defined in accordance with a torque dependent scaling factor calculated in response to the torque command.
    Type: Application
    Filed: September 17, 2007
    Publication date: March 19, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: STEVEN E. SCHULZ, GORO TAMAI, SCOTT THOMPSON
  • Publication number: 20090069142
    Abstract: Methods and systems for driving an automobile are provided. The system includes a prime mover power source and a two-mode, compound-split, electromechanical transmission, including first and second motors, coupled to the prime mover power source, a power inverter coupled to the first and second motors, and a processor coupled to the first and second motors and the power inverter. The processor is configured to modify a signal controlling the power inverter utilizing a first voltage distortion compensation method if a modulation index of the signal is less than a first modulation index value and modify the signal utilizing a second voltage distortion compensation method if the modulation index is at least equal to the first modulation index value.
    Type: Application
    Filed: September 12, 2007
    Publication date: March 12, 2009
    Inventors: Brian A. Welchko, Steven E. Schulz, 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: 20080303470
    Abstract: A motor control processor is provided for motor phase current sampling of multiple variable frequency controlled electric motors. The motor control processor comprises an analog-to-digital (A/D) converter and a controller. The A/D converter has multiple analog inputs and generates a digital output signal in response to the multiple analog inputs. The controller is coupled to the A/D converter and determines a maximum desired switching frequency for a first one of the multiple variable frequency controlled electric motors. The controller further selects a base period in response to the maximum desired switching frequency and defines a phase shift time delay as a fraction of the base period so that the controller may control the multiple analog inputs of the A/D converter to sample motor phase currents of each of the multiple variable frequency controlled electric motors at sample times determined by the controller in response to the base period and the phase shift time delay.
    Type: Application
    Filed: June 6, 2007
    Publication date: December 11, 2008
    Inventors: Steven E. Schulz, Terry Murrell
  • Publication number: 20080303475
    Abstract: Methods and systems are provided for controlling permanent magnet machines. The method includes determining a maximum torque of the PM machine based on an error between a commanded d-axis flux and an estimated d-axis flux of the PM machine, and adjusting a torque command based on the maximum torque. The error associated with a variation between a current temperature and a nominal temperature of the PM machine.
    Type: Application
    Filed: June 7, 2007
    Publication date: December 11, 2008
    Inventors: Nitinkumar R. Patel, Brian A. Welchko, Bonho Bae, Steven E. Schulz
  • 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: 7459874
    Abstract: Methods, apparatus, and systems are provided for regulating the operation of a drive system within a battery voltage and power range. The apparatus includes a PI regulator producing a signal for regulating a torque output of the drive system based on a DC voltage source limit and/or power limit, a converter normalizing the signal from the PI regulator to produce a new torque limit, and a switch selecting either the new torque limit or an available torque limit of the drive system. The PI regulator includes an integrator having an initial value based on the torque output of the drive system and a copper loss term.
    Type: Grant
    Filed: February 20, 2007
    Date of Patent: December 2, 2008
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Bon-Ho Bae, Steven E. Schulz, Nitinkumar R. Patel