The book discusses the systems of thyristor self-excitation of powerful synchronous generators and the features of their operation in various operating modes. The results of studies of overvoltages, emergency currents and high-frequency oscillations in excitation circuits of machines with semiconductor valves are given. Exact forms are obtained for determination of harmonic components and active values of phase currents. Particular attention is paid to the influence of excitation and ARV systems on the stability and parameters of synchronous generators, as well as excitation systems of superconducting turbogenerators, short-term generators and machines with longitudinal-transverse rotor windings.