Excitation control design based on nonlinearities compensation technique for voltage regulation in power systems

The paper presents the excitation control design of synchronous generators aimed at voltage regulation in power systems. The design is based on the use of the non-linearities compensation technique. The models of the electrical network and synchronous generator are suitably rearranged into a input-output model with non-linear terms. With the help of an RLS-based estimation algorithm these non-linear terms are cancelled by a compensating law and a new input is introduced to design a feedback controller using the root-locus technique. The compensating law, which is valid in the whole operating region of the synchronous generator, is implementable starting from the estimates output by the RLS algorithm and from physical variables. Changes in the power system operating conditions which may determine variations in the model parameters are detected by the estimation algorithm. Numerical simulation shows that the voltage regulation objective is accomplished applying the proposed design.