Abstract: A motor drive system and method for controlling an electric motor. The motor drive system includes a plurality of phase lines switchably connected to the electric motor, a plurality of controllable switches, and a controller. The controller is communicatively coupled to the plurality of controllable switches and configured to receive a signal indicative of a rotor speed and a rotor position from the rotor sensor. The controller generates a value expressing a back-electromotive force (back-EMF) as a function of the rotor position with respect to a rotating frame of reference. Based on the rotor position, the controller determines a plurality of phase currents that reduce a torque ripple of the electric motor to approximately zero. The controller actuates the controllable switches to supply the electric motor with the plurality of phase currents.

Abstract: A motor drive system and method for controlling an electric motor. The motor drive system includes a plurality of phase lines switchably connected to the electric motor, a plurality of controllable switches, and a controller. The controller is communicatively coupled to the plurality of controllable switches and configured to receive a signal indicative of a rotor speed and a rotor position from the rotor sensor. The controller generates a value expressing a back-electromotive force (back-EMF) as a function of the rotor position with respect to a rotating frame of reference. Based on the rotor position, the controller determines a plurality of phase currents that reduce a torque ripple of the electric motor to approximately zero. The controller actuates the controllable switches to supply the electric motor with the plurality of phase currents.

Abstract: Magnetic or electric field sensors are mounted against a material surface and used for stress, strain, and load monitoring of rotating components such as vehicle drive trains. The stationary sensors are mounted at multiple locations around the component and used assess the stress on the component at multiple rotational positions. The sensor response is typically converted into a material property, such as magnetic permeability or electrical conductivity, which accounts for any coating thickness that may be present between the sensor and mounting surface. The sensors are not in direct contact with the rotating component and are typically mounted on an annular material or ring that encircles the rotating component. Measurements of the annular material properties, such as the stress, are related to the stress on the rotating component and discrete features on the component.