Patents by Inventor Jackson Wai
Jackson Wai 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: 20150127207Abstract: A control system for a generator of an electric drive is provided. The control system may include a converter circuit configured to communicate with one or more phases of a stator of the generator, and a controller in communication with the converter circuit and an engine associated with the electric drive. The controller may be configured to determine an operational state of the electric drive based on at least engine speed, and engage one of a map-lookup control scheme and a fixed-theta off control scheme for operating the generator based on the operational state of the electric drive.Type: ApplicationFiled: January 14, 2015Publication date: May 7, 2015Inventors: Jackson Wai, Thuong Le, Adam Braun, Jesse Gerdes, James Siegle, Mark Hartman
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Patent number: 8975878Abstract: A method of controlling a generator (110) of an electric drive (104) associated with an engine (102) is provided. The method may determine an operational state of the electric drive (104) based on a speed of the engine (102), and selectively engage one of a map-lookup control scheme (150) and a fixed-theta off control scheme (152) for operating the generator (110) based on the operational state of the electric drive (104).Type: GrantFiled: December 23, 2010Date of Patent: March 10, 2015Assignee: Caterpillar Inc.Inventors: Jackson Wai, Thuong Le, Adam Braun, Jesse Gerdes, James Siegle, Mark Hartman
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Patent number: 8975855Abstract: A control system for compensating a hysteresis band of a switched reluctance (SR) machine having a rotor and a stator is provided. The control system may include a converter circuit and a controller. The converter circuit may be operatively coupled to the stator and include a plurality of switches in selective communication with each phase of the stator. The controller may be in communication with each of the stator and the converter circuit, and configured to monitor at least one phase current of the SR machine relative to a current threshold of the hysteresis band, determine an adjustment value based on a difference between the phase current and the current threshold if the phase current exceeds the current threshold, and compensate the current threshold by the adjustment value.Type: GrantFiled: July 23, 2012Date of Patent: March 10, 2015Assignee: Caterpillar Inc.Inventors: Jesse Gerdes, Jackson Wai, Ahmed Khalil
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Patent number: 8970291Abstract: A method of debouncing a variable frequency step signal is provided. The method includes the steps of: (a) determining a first period in oscillations of the variable frequency step signal and applying a first debounce time to debounce oscillations in the variable frequency step signal, (b) detecting a second period in the oscillations of the variable frequency step signal, (c) calculating a second debounce time as a fraction of the first period, (d) applying the second debounce time to debounce oscillations having the second period, and (e) repeating the steps (b)-(d) for debouncing successive oscillations of varying periods in the variable frequency step signal.Type: GrantFiled: December 10, 2013Date of Patent: March 3, 2015Assignee: Caterpillar Inc.Inventors: Jesse R Gerdes, Jackson Wai, Benjamin Paul Gottemoller, Sangameshwar Sonth
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Publication number: 20150028788Abstract: A method of controlling a motor is provided. The method may determine one of a switching period, a fundamental cycle, and a current target per phase leg of the motor having at least one high voltage transition point; determine a dwell period to be enforced at the transition point between an engagement of a first switch of the phase leg and an engagement of a second switch of the phase leg where each of the first switch and the second switch may be selectively engageable between a first state and a second state; engage the first switch from the first state to the second state at the transition point; and engage the second switch from the first state to the second state after the transition point and upon expiration of the dwell period.Type: ApplicationFiled: July 25, 2013Publication date: January 29, 2015Applicant: Caterpillar, Inc.Inventors: Jackson Wai, Ahmed Khalil, Carlos Nino Baron, Jesse Gerdes, Brad A. Kough
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Patent number: 8901869Abstract: A method of controlling speed of an electric machine having a rotor and a stator is provided. The method may comprise the steps of monitoring a desired speed and a measured speed of the rotor, generating a torque command based on the desired speed and the measured speed, and controlling phase current to the stator based on a hybrid closed loop analysis of the torque command, the measured speed and an estimated position of the rotor. The estimated rotor position may be derived at least partially from the desired speed.Type: GrantFiled: July 31, 2012Date of Patent: December 2, 2014Assignee: Caterpillar Inc.Inventors: Jackson Wai, Jesse Gerdes, James Michael Thorne
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Patent number: 8901760Abstract: A machine is described that includes an electric drive for propelling the machine along a ground surface. The machine includes an electric power supply system configured to deliver operating electrical power to the electric drive. The electric power system includes a first generator and a second generator. The electric power system also includes a first rectifier coupled to the first generator and having a first direct current (DC) output and a second rectifier coupled to the second generator and having a second DC output. Both the first DC output and the second DC output are coupled to the single DC bus, thereby providing an arrangement for the first rectifier and the second rectifier to simultaneously provide power to the single DC bus. The electrical power system also includes a first inverter/controller coupled to the single DC bus and configured to provide a controlled alternating current to a first motor.Type: GrantFiled: January 28, 2013Date of Patent: December 2, 2014Assignee: Caterpillar Inc.Inventors: Jackson Wai, Robert R. Sychra, Robert W. Lindsey, Thomas M. Sopko, Bruce H. Hein
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Patent number: 8866433Abstract: A method of estimating an initial rotor position of a switched reluctance (SR) machine having a rotor and a stator is provided. The method may comprise the steps of driving a phase current in each of a plurality of phases of the SR machine to a predefined limit, performing an integration of a common bus voltage associated with each phase, determining a flux value for each phase based on the integrations, and determining the initial rotor position based on the flux values.Type: GrantFiled: October 31, 2012Date of Patent: October 21, 2014Assignee: Caterpillar Inc.Inventors: Jesse Gerdes, Jackson Wai, Mark Hartman, Ahmed Khalil, Carlos Nino Baron
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Publication number: 20140210208Abstract: A machine is described that includes an electric drive for propelling the machine along a ground surface. The machine includes an electric power supply system configured to deliver operating electrical power to the electric drive. The electric power system includes a first generator and a second generator. The electric power system also includes a first rectifier coupled to the first generator and having a first direct current (DC) output and a second rectifier coupled to the second generator and having a second DC output. Both the first DC output and the second DC output are coupled to the single DC bus, thereby providing an arrangement for the first rectifier and the second rectifier to simultaneously provide power to the single DC bus. The electrical power system also includes a first inverter/controller coupled to the single DC bus and configured to provide a controlled alternating current to a first motor.Type: ApplicationFiled: January 28, 2013Publication date: July 31, 2014Applicant: CATERPILLAR INC.Inventors: Jackson Wai, Robert R. Sychra, Robert W. Lindsey, Thomas M. Sopko, Bruce H. Hein
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Publication number: 20140203760Abstract: A method for controlling a hybrid machine is disclosed. The hybrid machine may be equipped with a turbine engine, a generator connected in series with the turbine engine, an electrical energy storage device, and a motor drivingly connected to a power output component for the hybrid machine. A controller may receive a power demand signal, determine a power level in the electrical energy storage device, determine available inertial energy stored at least in rotating components of the turbine engine and the generator, and provide one or more control signals to selectively control powering the turbine engine to full power, selectively turn off all fuel to the turbine engine, selectively store excess energy as electrical energy by directing excess electrical energy from the generator to the electrical energy storage device, and selectively store excess energy as inertial energy.Type: ApplicationFiled: January 18, 2013Publication date: July 24, 2014Applicant: CATERPILLAR INC.Inventors: Bryan Gerard LAMMERS, Daniel Edward HENDERSON, James Allen ROAL, Jackson WAI
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Patent number: 8773056Abstract: A control system for a switched reluctance (SR) machine is provided. The control system may include a converter circuit that is operatively coupled to the SR machine, and a controller in communication with the converter circuit. The controller may be configured to execute two or more processes in parallel, wherein the processes include generating a torque command based on one or more of bus voltage, machine current, rotor speed and rotor position, determining a first set of current control parameters based on the torque command and the rotor speed, determining a second set of current control parameters based on one or more of the torque command, the rotor speed and the rotor position, selecting one of the first and second sets of current control parameters based on the rotor speed, and operating the gates according to the selected set of current control parameters.Type: GrantFiled: June 11, 2012Date of Patent: July 8, 2014Assignee: Caterpillar Inc.Inventors: Jesse Gerdes, James Siegle, Mark Hartman, Aaron Luther Thomas, Jackson Wai
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Patent number: 8746382Abstract: A method of priming a common bus of a machine having an engine, a generator and an auxiliary power source is provided. The method may determine an operational state of the auxiliary power source, operate the engine at a predetermined idle speed if the auxiliary power source is determined to be inoperative, and enable the generator to regulate the common bus in response to the predetermined idle speed of the engine.Type: GrantFiled: December 23, 2010Date of Patent: June 10, 2014Assignee: Caterpillar Inc.Inventors: Jackson Wai, Thuong Le, Timothy Goldammer
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Publication number: 20140117901Abstract: A method of estimating an initial rotor position of a switched reluctance (SR) machine having a rotor and a stator is provided. The method may comprise the steps of driving a phase current in each of a plurality of phases of the SR machine to a predefined limit, performing an integration of a common bus voltage associated with each phase, determining a flux value for each phase based on the integrations, and determining the initial rotor position based on the flux values.Type: ApplicationFiled: October 31, 2012Publication date: May 1, 2014Applicant: CATERPILLAR INC.Inventors: Jesse Gerdes, Jackson Wai, Mark Hartman, Ahmed Khalil, Carlos Nino Baron
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Publication number: 20140035505Abstract: A method of controlling speed of an electric machine having a rotor and a stator is provided. The method may comprise the steps of monitoring a desired speed and a measured speed of the rotor, generating a torque command based on the desired speed and the measured speed, and controlling phase current to the stator based on a hybrid closed loop analysis of the torque command, the measured speed and an estimated position of the rotor. The estimated rotor position may be derived at least partially from the desired speed.Type: ApplicationFiled: July 31, 2012Publication date: February 6, 2014Applicant: CATERPILLAR, INC.Inventors: Jackson Wai, Jesse Gerdes, James Michael Thorne
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Publication number: 20140021889Abstract: A control system for compensating a hysteresis band of a switched reluctance (SR) machine having a rotor and a stator is provided. The control system may include a converter circuit and a controller. The converter circuit may be operatively coupled to the stator and include a plurality of switches in selective communication with each phase of the stator. The controller may be in communication with each of the stator and the converter circuit, and configured to monitor at least one phase current of the SR machine relative to a current threshold of the hysteresis band, determine an adjustment value based on a difference between the phase current and the current threshold if the phase current exceeds the current threshold, and compensate the current threshold by the adjustment value.Type: ApplicationFiled: July 23, 2012Publication date: January 23, 2014Applicant: CATERPILLAR, INC.Inventors: Jesse Gerdes, Jackson Wai, Ahmed Khalil
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Patent number: 8624543Abstract: A method of controlling a motor is provided. The method may determine a speed of the motor, and engage a soft chopping routine on a first switch and a second switch of each phase if the motor speed is relatively low. The first switch may be driven by a first pulse width modulated PWM signal and the second switch being driven by a second PWM signal. The first and second PWM signals may be alternatingly configured such that at least one of the first switch and the second switch is closed at any point during the distributed soft chopping routine and both the first switch and the second switch are never simultaneously open.Type: GrantFiled: December 9, 2011Date of Patent: January 7, 2014Assignee: Caterpillar Inc.Inventors: Ahmed Khalil, Jackson Wai, Jesse Gerdes, James Siegle, Mark Hartman, Joshua Williams
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Patent number: 8624564Abstract: A method of estimating rotor speed of a generator 106 having a rotor 110 and a stator 112 is provided. The method may provide a source current to the stator 112, determine a relative rotor speed based on a sensor signal provided by a rotor speed sensor 130, determine a relative rotor position corresponding to the relative rotor speed, determine an absolute rotor position based on the sensor signal and phase currents, and calibrate the sensor signal based on an offset between the relative rotor position and the absolute rotor position.Type: GrantFiled: May 31, 2011Date of Patent: January 7, 2014Assignee: Caterpillar Inc.Inventors: Mark Hartman, Robert Lindsey, Jackson Wai, Jesse Gerdes
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Patent number: 8610382Abstract: A method of actively discharging a common bus (116) of a machine (100) having an engine (102), a generator (112), a traction motor (124) and one or more auxiliary devices (126) is provided. The method may monitor a speed of the engine (102) with respect to a first threshold, monitor a voltage of the common bus (116) with respect to a second threshold, and enable one or more of the generator (112), the motor (124) and the auxiliary devices (126) if the engine speed falls below the first threshold and the voltage exceeds the second threshold so as to discharge voltage from the common bus (116).Type: GrantFiled: December 23, 2010Date of Patent: December 17, 2013Assignee: Caterpillar Inc.Inventors: Timothy Goldammer, Thuong Le, Jason Miller, Jackson Wai
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Publication number: 20130328517Abstract: A control system for a switched reluctance (SR) machine is provided. The control system may include a converter circuit that is operatively coupled to the SR machine, and a controller in communication with the converter circuit. The controller may be configured to execute two or more processes in parallel, wherein the processes include generating a torque command based on one or more of bus voltage, machine current, rotor speed and rotor position, determining a first set of current control parameters based on the torque command and the rotor speed, determining a second set of current control parameters based on one or more of the torque command, the rotor speed and the rotor position, selecting one of the first and second sets of current control parameters based on the rotor speed, and operating the gates according to the selected set of current control parameters.Type: ApplicationFiled: June 11, 2012Publication date: December 12, 2013Applicant: CATERPILLAR, INC.Inventors: Jesse Gerdes, James Siegle, Mark Hartman, Aaron Luther Thomas, Jackson Wai
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Publication number: 20130154535Abstract: A protection circuit includes a first switch, a second switch and a third switch. The first switch, the second switch and the third switch are configured to generate lock signals indicative of an electrical voltage transition on the respective phases of a multi-phase power signal. A control circuit is configured to prevent the first switch from changing state if the second switch or third switch is changing state.Type: ApplicationFiled: December 14, 2011Publication date: June 20, 2013Applicant: CATERPILLAR INC.Inventors: Jackson Wai, Mark Hartman, Thuong Le, Jesse Gerdes