Abstract: 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.

Abstract: 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.

Abstract: A solar energy system and method of cleaning photovoltaic panels is provided. Measurements relating to weather at a photovoltaic panel are received by the system. Measurements relating to output current and voltage at the photovoltaic panel are received by the system. Expected power of the photovoltaic panel is determined based on the measurements relating to weather. Actual power of the photovoltaic panel is determined based on the measurements relating to output current and voltage. In response to determining that the actual power is not within a predetermined range of the expected power (e.g. at least one photovoltaic panel is dirty), a cleaning of the photovoltaic panel is initiated.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A solar energy system and method of cleaning photovoltaic panels is provided. Measurements relating to weather at a photovoltaic panel are received by the system. Measurements relating to output current and voltage at the photovoltaic panel are received by the system. Expected power of the photovoltaic panel is determined based on the measurements relating to weather. Actual power of the photovoltaic panel is determined based on the measurements relating to output current and voltage. In response to determining that the actual power is not within a predetermined range of the expected power (e.g. at least one photovoltaic panel is dirty), a cleaning of the photovoltaic panel is initiated.

Abstract: A turf machine is disclosed having a body with an engine and a mower deck. The turf machine has a plurality of track drives coupled to the engine. The turf machine further has a forward power coupling which transfers power from the engine to the mower deck.

Abstract: A lid includes a top having a cover receiving portion having a first aperture and a second aperture formed therein, a hinge positioned about a center of the cover receiving portion such that the first aperture is on one side of the hinge and the second aperture is on an opposite side of the hinge, and a cover having two directly opposing sidewalls rotatably attached to the cover receiving portion via the hinge. Each sidewall includes a protrusion extending therefrom shaped to fit within one of the first and second apertures. The cover pivots relative to the cover receiving portion so as to engage either the first aperture or the second aperture, and when the protrusion on one sidewall of the cover is pivoted towards the first aperture, the protrusion on the other sidewall simultaneously pivots away from the second aperture.

Abstract: A lid includes a flat portion having a first aperture and a second aperture formed therein, a hinge positioned about a center of the flat portion such that the first aperture is on one side of the hinge and the second aperture is on an opposite side of the hinge, a cover, having two directly opposing sidewalls each with a protrusion, rotatably attached to the flat portion via the hinge, a valve housing integrally formed with the flat portion, a valve, and a valve retainer for retaining the valve within the valve housing. The cover pivots relative to the flat portion so as to engage either the first aperture or the second aperture, and when the protrusion on one sidewall of the cover is pivoted towards the first aperture, the protrusion on the other sidewall simultaneously pivots away from the second aperture.

Abstract: A lid includes a top having a cover receiving portion having a first aperture and a second aperture formed therein, a hinge positioned about a center of the cover receiving portion such that the first aperture is on one side of the hinge and the second aperture is on an opposite side of the hinge, and a cover having two directly opposing sidewalls rotatably attached to the cover receiving portion via the hinge. Each sidewall includes a protrusion extending therefrom shaped to fit within one of the first and second apertures. The cover pivots relative to the cover receiving portion so as to engage either the first aperture or the second aperture, and when the protrusion on one sidewall of the cover is pivoted towards the first aperture, the protrusion on the other sidewall simultaneously pivots away from the second aperture.