Patents by Inventor Thomas A. Nondahl
Thomas A. Nondahl 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).
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Publication number: 20130286704Abstract: Cascade H-Bridge inverters and carrier-based level shift pulse width modulation techniques are presented for generating inverter stage switching control signals, in which carrier waveform levels are selectively shifted to control THD and to mitigate power distribution imbalances within multilevel inverter elements.Type: ApplicationFiled: April 27, 2012Publication date: October 31, 2013Applicant: ROCKWELL AUTOMATION TECHNOLOGIES, INC.Inventors: Jingbo Liu, Thomas Nondahl, Zhongyuan Cheng, Navid Zargari
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Patent number: 8547050Abstract: Systems, methods, and devices are disclosed, including an induction-motor controller having a phase path; a solid-state switch interposed on the phase path; and a controller coupled to the solid-state switch. In certain embodiments, the controller is configured to switch the solid-state switch so that the solid-state switch is conductive during a conduction angle of a cycle of an incoming AC power waveform conveyed by the phase path, calculate the conduction angle based on a generally sinusoidal reference value that has a frequency lower than a frequency of the incoming AC power waveform, and adjust the generally sinusoidal reference value based on a value indicative of flux in a load coupled to the phase path.Type: GrantFiled: May 17, 2012Date of Patent: October 1, 2013Assignee: Rockwell Automation Technologies, Inc.Inventors: Haihui Lu, David M. Messersmith, Thomas A. Nondahl
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Patent number: 8497655Abstract: The present invention provides a simple, robust, and universal position observer for use with sensorless synchronous machines. The observer may be implemented using an equivalent EMF model of a synchronous machine or, alternately, using a sliding mode controller based on the equivalent EMF model of the synchronous machine. The observer may be used on any type of synchronous machine, including salient or non-salient pole machines such as a permanent magnet, interior permanent magnet, wound rotor, or reluctance synchronous machine. The observer provides low sensitivity to parameter variations and disturbances or transient conditions in the machine. In addition, no knowledge of speed is required as an input to the observer and an estimated position may be calculated using a subset of the machine parameters.Type: GrantFiled: June 26, 2012Date of Patent: July 30, 2013Assignee: Rockwell Automation Technologies, Inc.Inventors: Jingbo Liu, Semyon Royak, Mark M. Harbaugh, Thomas A. Nondahl, Peter B. Schmidt
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Patent number: 8330405Abstract: The present invention provides an improved current regulator for PWM based drives for electric motors. The invention provides compensation for the rotor position signal for delays introduced due to the PWM algorithm and for digital sampling present in such a drive. Current regulator commonly operate in a two-phase reference frame, requiring forward and reverse coordinate transformations between the physical current values and the two-phase reference frame variables. The present invention provides an improved compensation in the forward transformation by determining the phase lag between the commanded voltage reference and the output voltage reference and by further compensating the forward transformation for errors introduced due to sampling the current either at different sampling instances than the rotor position or at multiple sampling instances during a carrier period.Type: GrantFiled: June 18, 2009Date of Patent: December 11, 2012Assignee: Rockwell Automation Technologies, Inc.Inventors: Semyon Royak, Mark M. Harbaugh, Thomas A. Nondahl, Jingbo Liu, Peter B. Schmidt, Robert J. Breitzmann
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Publication number: 20120268050Abstract: The present invention provides a simple, robust, and universal position observer for use with sensorless synchronous machines. The observer may be implemented using an equivalent EMF model of a synchronous machine or, alternately, using a sliding mode controller based on the equivalent EMF model of the synchronous machine. The observer may be used on any type of synchronous machine, including salient or non-salient pole machines such as a permanent magnet, interior permanent magnet, wound rotor, or reluctance synchronous machine. The observer provides low sensitivity to parameter variations and disturbances or transient conditions in the machine. In addition, no knowledge of speed is required as an input to the observer and an estimated position may be calculated using a subset of the machine parameters.Type: ApplicationFiled: June 26, 2012Publication date: October 25, 2012Inventors: Jingbo Liu, Semyon Royak, Mark M. Harbaugh, Thomas A. Nondahl, Peter B. Schmidt
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Publication number: 20120223668Abstract: Systems, methods, and devices are disclosed, including an induction-motor controller having a phase path; a solid-state switch interposed on the phase path; and a controller coupled to the solid-state switch. In certain embodiments, the controller is configured to switch the solid-state switch so that the solid-state switch is conductive during a conduction angle of a cycle of an incoming AC power waveform conveyed by the phase path, calculate the conduction angle based on a generally sinusoidal reference value that has a frequency lower than a frequency of the incoming AC power waveform, and adjust the generally sinusoidal reference value based on a value indicative of flux in a load coupled to the phase path.Type: ApplicationFiled: May 17, 2012Publication date: September 6, 2012Applicant: ROCKWELL AUTOMATION TECHNOLOGIES, INC.Inventors: Haihui Lu, David M. Messersmith, Thomas A. Nondahl
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Patent number: 8228013Abstract: A method and apparatus for determining electrical parameters for commissioning a sensor-less permanent magnet synchronous machine uses knowledge of the rotor position to apply balanced pulses along the rotor magnet axis and perpendicular to the rotor magnet axis allowing measurement of q- and d-inductance at multiple current levels without substantial rotor movement.Type: GrantFiled: September 10, 2008Date of Patent: July 24, 2012Assignee: Rockwell Automation Technologies, Inc.Inventors: Jingbo Liu, Mark M. Harbaugh, Thomas A Nondahl, Peter B. Schmidt, Semyon Royak
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Patent number: 8203304Abstract: Systems, methods, and devices are disclosed, including an induction-motor controller having a phase path; a solid-state switch interposed on the phase path; and a controller coupled to the solid-state switch. In certain embodiments, the controller is configured to switch the solid-state switch so that the solid-state switch is conductive during a conduction angle of a cycle of an incoming AC power waveform conveyed by the phase path, calculate the conduction angle based on a generally sinusoidal reference value that has a frequency lower than a frequency of the incoming AC power waveform, and adjust the generally sinusoidal reference value based on a value indicative of flux in a load coupled to the phase path.Type: GrantFiled: August 31, 2007Date of Patent: June 19, 2012Assignee: Rockwell Automation Technologies, Inc.Inventors: Haihui Lu, David M. Messersmith, Thomas A. Nondahl
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Patent number: 8159168Abstract: A method for estimating a rotor position in an electrical machine is provided. The method is applicable to electrical machines that have magnetic saliency. The method includes extracting the rotor position from a demodulated output signal generated in response to an injected high frequency carrier signal and determining a position error compensation based upon a demodulation delay and a velocity or rotational frequency of the electrical machine. The method also includes estimating the rotor position by applying the position error compensation to the extracted rotor position.Type: GrantFiled: May 29, 2009Date of Patent: April 17, 2012Assignee: Rockwell Automation Technologies, Inc.Inventors: Jingbo Liu, Thomas Nondahl, Peter B. Schmidt, Semyon Royak, Mark H. Harbaugh
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Patent number: 7944164Abstract: A method and apparatus for determining rotor position in a stationary rotor of a sensor-less permanent magnet synchronous machine that employs a rotating magnetic field to identify a magnetic axis of the stator without a magnetic direction and then determines magnetic direction by applying pulses along the magnet axis in two polarities.Type: GrantFiled: July 31, 2008Date of Patent: May 17, 2011Assignee: Rockwell Automation Technologies, Inc.Inventors: Jingbo Liu, Thomas Nondahl, Peter Schmidt, Semyon Royak, Mark Harbaugh
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Publication number: 20110102012Abstract: A method of estimating stator resistance of an induction motor is provided. The method includes applying voltage pulses through two phase paths of the motor for a plurality of electrical cycles to inject current in the motor, wherein the voltage pulses are applied until rotor flux of the motor is substantially stabilized and measuring stator voltage and stator current in response to the applied voltage pulses for each of the plurality of electrical cycles. The method also includes calculating the stator resistance based upon the measured stator voltages and the stator currents.Type: ApplicationFiled: November 3, 2009Publication date: May 5, 2011Applicant: Rockwell Automation Technologies, Inc.Inventors: David M. Messersmith, Douglas J. Bader, Haihui Lu, Thomas A. Nondahl, Zhenhuan Yuan
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Patent number: 7915852Abstract: The invention includes a motor controller and method for controlling a permanent magnet motor. In accordance with one aspect of the present technique, a permanent magnet motor is controlled by, among other things, receiving a torque command, determining a normalized torque command by normalizing the torque command to a characteristic current of the motor, determining a normalized maximum available voltage, determining an inductance ratio of the motor, and determining a direct-axis current based upon the normalized torque command, the normalized maximum available voltage, and the inductance ratio of the motor.Type: GrantFiled: February 22, 2008Date of Patent: March 29, 2011Assignee: Rockwell Automation Technologies, Inc.Inventors: Semyon Royak, Mark M. Harbaugh, Robert J. Breitzmann, Thomas A. Nondahl, Peter B. Schmidt, Jingbo Liu
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Patent number: 7868581Abstract: An induction motor controller that may include three phase paths leading from a power input to a power output, a solid-state switching device interposed between the power input and the power output on each of the three phase paths, a voltage sensor coupled to two of the phase paths between the solid-state switching device and the power input, a current sensor on one of the phase paths, a processor communicatively coupled to the voltage sensor, the current sensor, and the solid state switching device; and a memory coupled to the processor. The processor may be configured to calculate a motor parameter based on a signal from the voltage sensor and a signal from the current sensor and store the calculated motor parameter in memory.Type: GrantFiled: February 28, 2008Date of Patent: January 11, 2011Assignee: Rockwell Automation Technologies, Inc.Inventors: Wei Qian, Haihui Lu, Thomas A. Nondahl
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Publication number: 20100320948Abstract: The present invention provides an improved current regulator for PWM based drives for electric motors. The invention provides compensation for the rotor position signal for delays introduced due to the PWM algorithm and for digital sampling present in such a drive. Current regulator commonly operate in a two-phase reference frame, requiring forward and reverse coordinate transformations between the physical current values and the two-phase reference frame variables. The present invention provides an improved compensation in the forward transformation by determining the phase lag between the commanded voltage reference and the output voltage reference and by further compensating the forward transformation for errors introduced due to sampling the current either at different sampling instances than the rotor position or at multiple sampling instances during a carrier period.Type: ApplicationFiled: June 18, 2009Publication date: December 23, 2010Inventors: Semyon Royak, Mark M. Harbaugh, Thomas A. Nondahl, Jingbo Liu, Peter B. Schmidt, Robert J. Breitzmann
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Publication number: 20100301790Abstract: A method for estimating a rotor position in an electrical machine is provided. The method is applicable to electrical machines that have magnetic saliency. The method includes extracting the rotor position from a demodulated output signal generated in response to an injected high frequency carrier signal and determining a position error compensation based upon a demodulation delay and a velocity or rotational frequency of the electrical machine. The method also includes estimating the rotor position by applying the position error compensation to the extracted rotor position.Type: ApplicationFiled: May 29, 2009Publication date: December 2, 2010Applicant: Rockwell Automation Technologies, Inc.Inventors: Jingbo Liu, Thomas Nondahl, Peter B. Schmidt, Semyon Royak, Mark M. Harbaugh
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Patent number: 7701165Abstract: An induction motor controller that may include three phase paths leading from a power input to a power output, a solid-state switching device interposed between the power input and the power output on each of the three phase paths, a voltage sensor coupled to two of the phase paths between the solid-state switching device and the power output, a current sensor on one of the phase paths, a processor communicatively coupled to the voltage sensor, the current sensor, and the solid state switching device; and a memory coupled to the processor. The processor may be configured to calculate a motor parameter based on a signal from the voltage sensor and a signal from the current sensor and store the calculated motor parameter in memory.Type: GrantFiled: October 31, 2007Date of Patent: April 20, 2010Assignee: Rockwell Automation Technologies, Inc.Inventors: Wei Quian, Haihui Lu, Thomas A. Nondahl
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Publication number: 20100060210Abstract: A method and apparatus for determining electrical parameters for commissioning a sensor-less permanent magnet synchronous machine uses knowledge of the rotor position to apply balanced pulses along the rotor magnet axis and perpendicular to the rotor magnet axis allowing measurement of q- and d-inductance at multiple current levels without substantial rotor movement.Type: ApplicationFiled: September 10, 2008Publication date: March 11, 2010Inventors: Jingbo Liu, Mark M. Harbaugh, Thomas A. Nondahl, Peter B. Schmidt, Semyon Royak
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Patent number: 7672096Abstract: An improved switching apparatus and method are disclosed. In at least some embodiments, the apparatus includes first and second ports, a first switching device such as a contactor coupled between the ports, and a second switching device coupled in parallel with the contactor between the ports, where the second switching device can be or include a solid-state semiconductor device. The second switching device is operated to become conductive at a first time prior to a second time when the contactor switches between a conductive state and a non-conductive state, and remains conductive up to a third time subsequent to the second time. In at least some further embodiments, the apparatus also includes one or both of a voltage sensing capability and a current sensing capability and switches the second switching device to become conductive based upon voltage and/or current information.Type: GrantFiled: September 29, 2006Date of Patent: March 2, 2010Assignee: Rockwell Automation Technologies, Inc.Inventors: David M. Messersmith, Thomas A. Nondahl
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Publication number: 20100026223Abstract: A method and apparatus for determining rotor position in a stationary rotor of a sensor-less permanent magnet synchronous machine that employs a rotating magnetic field to identify a magnetic axis of the stator without a magnetic direction and then determines magnetic direction by applying pulses along the magnet axis in two polarities.Type: ApplicationFiled: July 31, 2008Publication date: February 4, 2010Inventors: Jingbo Liu, Thomas Nondahl, Peter Schmidt, Semyon Royak, Mark Harbaugh
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Patent number: 7609014Abstract: A system and method for controlling any of a variety of permanent magnet motors includes normalizing motor parameters with respect to demagnetization current of a motor and developing a torque-per-current relationship using the normalized motor parameters at approximately maximum torque. Using the developed torque-per-current relationship, it is possible to control any of a variety of permanent magnet motors without the need for extensive configuration of a motor control unit for a specific motor.Type: GrantFiled: October 19, 2006Date of Patent: October 27, 2009Assignee: Rockwell Automation Technologies, Inc.Inventors: Semyon Royak, Jingbo Liu, Peter B. Schmidt, Thomas A. Nondahl, Mark Melvin Harbaugh, Robert John Breitzman