An Improved Structure of an Adaptive Excitation Control System Operating under Short-Circuit

The paper presents an extended structure for a minimum variance adaptive control system of an induction generator, which aims to improve its operating behavior under electrical short-circuit conditions. The basic design idea is to limit the control to physically achievable values, and thus increasing the robustness of the control system and avoiding an instability regime. A control limiting block is proposed and used for this purpose. Moreover, a short-circuit detector enables an on-line setting of the control penalty factor, improving the quality of the controlled output. All these additional customizations of the control system, implemented to keep the plant operational under and after a short-time short-circuit fault (acting as an abnormal perturbation), must also provide good performance in the normal operating mode