Deere + Company

Anthony Weber

Long Wu

David Holmburg

Jared Lervik

Christopher L Marohl

Lav Thyagarajan

Yue Zhao

Whitney M Marohl

At least one example embodiment discloses a method of controlling an alternating current (ac) machine. The method includes determining or retrieving a current limit for the ac machine, determining a characterized peak current value based on a voltage-to-speed ratio of the ac machine, determining current command values for the ac machine based on at least one of the torque command limit and a torque command for the ac machine, determining current command values for the ac machine based on the torque command limit and controlling the ac machine based on the current command values.

Methods of controlling a machine using a torque command limit derived from a current limit and systems thereof

A current measurement module is adapted to measure an observed current level for the inverter. A data processor or mode controller accesses a stored representation of first current level versus rotor speed output at which a total harmonic distortion level is less than threshold total harmonic distortion level. The data processor or mode controller enables the inverter to use SVPWM (space vector pulse width modulation) if the observed current level is less than the first current level for the measured or determined rotor speed. Further, the data processor or mode controller enables the inverter to use DPWM (discontinuous pulse width modulation) if the observed current level is greater than or equal to the first current level for the measured or determined rotor speed.

System and method for controlling modulation of an inverter

At least one example embodiment discloses a method including measuring phase currents associated with one or more stator windings of the machine, estimating terminal voltage values based on the measured phase currents representations of the machine and based on at least one of a duty cycle and a dead time ratio of the machine, transforming the terminal voltage values to derive direct and quadrature voltage representations consistent with the measured phase currents, determining a terminal power of one or more terminals of the machine, the terminal power directly based on one of the estimated terminal voltage values and direct and quadrature voltage representations of the machine and current command values and determining an estimated shaft torque of the machine based on the terminal power in accordance with at least one efficiency value based on machine parameters from a characterization of the machine.

Methods of torque estimation and compensation and systems thereof

At least one example embodiment discloses a method of estimating a rotor magnet temperature of a motor. The method includes determining an applied voltage during operation of the motor at an operating point, obtaining a reference value associated with the operating point and associated with a reference temperature and determining an estimated rotor magnet temperature based on the applied voltage and the reference value.

Methods of estimating rotor magnet temperature and systems thereof

At least one example embodiment discloses a control device for controlling an alternating current (ac) machine. The control device includes a processor configured to select a modulation mode from a plurality of modulation modes, determine a plurality of present phase voltages corresponding to phases of an inverter based on the selected modulation mode, the determination compensating for deadtimes associated with the selected modulation mode and phases of the inverter, the inverter configured to drive the ac machine and determine an estimated terminal voltage based on the plurality of present phase voltages.

Growing community of inventors

Moline, IL, United States of America

Anthony Weber