Abstract: An apparatus includes a stator with an inner surface and an outer surface, a plurality of rotors magnetically coupled to the stator, wherein a first rotor faces the inner surface of the stator and a second rotor faces the outer surface of the stator, and a first airgap between the inner surface of the stator and the first rotor, and a second airgap between the outer surface of the stator and the second rotor, wherein first conductors, the first airgap, and the first rotor form a first submotor, and second conductors, the second airgap, and the second rotor form a second submotor, and wherein the first submotor and the second submotor are so configured that the first rotor and the second rotor produce mechanical torques in a same direction when currents flow in the plurality of windings in an operation mode.

Abstract: A system includes a motor having a plurality of windings, a rotor and a stator magnetically coupled to the rotor, a plurality of power inverters connected to respective windings, wherein the plurality of power inverters is configured to control currents of the plurality of windings, and a controller configured to determine an injection ratio of a high-order harmonic component to a fundamental component based on a performance index, and wherein the injection ratio for a magnetizing component is different from the injection ratio for a torque component at a same harmonic frequency.

Abstract: A system includes a vehicle having an engine, a first motor mechanically coupled to a shaft of the engine, a second motor configured to provide torque to the vehicle or the engine in combination with the first motor, and a first controller coupled to at least one of the first motor and the second motor, wherein the first controller is configured such that the first motor and the second motor provide a mechanical torque to rotate the shaft of the engine before the engine is running.