Effects of torsional dynamics on nonlinear generator control. II

The stability robustness of a feedback linearizing control is investigated with respect to a structured uncertainty for the particular application of an excitation controller on a synchronous electric generator. The uncertainty considered corresponds to the spring modes of the generator shaft, and enters in such a way that analysis by Kharitonov´s theorem is feasible. It is shown that the control remains stable over a wide range of values of the shaft parameters. A sliding control is designed and compared to the feedback linearizing control with respect to performance degradation for this type of uncertainty, and it is found that, because of the tight saturation limits on the control signal, the sliding control offers no discernable performance advantage for this type of structured uncertainty.