Solutions to avoid the worst case scenario in driving systems working under continuously variable conditions

The paper presents a study on the behavior of some control solutions for electric drive systems evolving in conditions of reference, disturbance and parameter variability. The results of this study substantiate new control solutions that ensure the possibility to avoid the worst cases. The study addresses the real situation of an electric drive system with continuously variable reference input (speed), variable moment of inertia and variable load disturbance. Two control structures with controllers with fixed parameters are considered and discussed with focus on the speed control loop. The justified new control structures employ the switching between several control algorithms; their design is based on the detailed mathematical model of the plant and on the particular features of the drive system. The solutions are validated by means of digital simulations and experiments on a laboratory equipment application for three values of the moment of inertia.