System for actively reducing rotational nonuniformity of a shaft, in particular, the drive shaft of an internal combustion engine, and method for this

A system for active reduction of rotational fluctuations of a shaft comprising an electrical machine (4), with the electrical machine (4) being controlled in such a way that

• in order to reduce rotational fluctuations, it produces a rapidly varying torque, wherein, if no mean accelerating or decelerating torque is generated, the rapidly varying torque defines a zero line and has a curved shape, and
• superimposes a positive or negative torque, respectively, over the rapidly varying torque to additionally generate a mean accelerating or decelerating or rheostatic braking torque,
• wherein as a result of such superimposition, the rapidly varying torque only shifts with respect to the zero line while maintaining the curved shape;
• and
• wherein the rapidly varying torque acts in an alternating manner, i.e. by decelerating in the case of a positive rotational fluctuation of the shaft and by accelerating in the case of a negative rotational fluctuation of the shaft.